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Accuracy and Precision of Mini-FLOTAC and McMaster Techniques for Determining Equine Strongyle Egg Counts
Abstract
The use of fecal egg count techniques to indirectly assess intestinal parasite burdens and determine anthelmintic efficacy is common in parasitological research and veterinary practice. The McMaster method is one of the most widely used techniques in veterinary practice, but recently, the Mini-FLOTAC technique has been introduced as a possible alternative. Studies comparing the two methods in precision and accuracy are needed. This study aimed at evaluating the Mini-FLOTAC technique for determining equine strongyle egg counts through a two-part procedure. First, a set of fecal counts was executed using both methods. Next, blind counts were performed on spiked fecal samples with true egg counts at 0, 5, 50, 500, and 1,000 eggs per gram. All counts were performed in triplicates, and each sample was counted using both methods. Mini-FLOTAC and McMaster had 83.2% and 53.7% precision, respectively. The accuracy was found to be 42.6% and 23.5% for Mini-FLOTAC and McMaster, respectively. In conclusion, this study found that Mini-FLOTAC exhibited both higher precision and accuracy than the McMaster technique and appears to be a more reliable alternative. Using a more precise egg-counting method can help assure that changes in egg counts before and after treatment reflect a genuine reduction and are not due to chance variability.
... Before examination, all samples were kept in a refrigerator (+ 4°C) for 1-2 days. Two coprological methods were performed to investigate Anoplocephala fecal egg counts (FEC); the mini-FLOTAC (Noel et al. 2017) and the double centrifugation/combined sedimentationflotation technique (Rehbein et al. 2011). To carry out the mini-FLOTAC technique, 5 g of samples were placed into a fill-FLOTAC device and dispersed with a 45 ml volume of glucose-NaCl solution (s.g. ...
... 1.25). The mini-FLOTAC chambers were filled with the 1 ml suspension and the FEC was computed after 10 min of flotation as reported by Noel et al. (2017). The FEC was recalculated to obtain eggs per gram (EPG) numbers using a multiplication factor of five. ...
... Only 1.99% of horses from 12.90% of the examined farms were found to be infected according to the coprological methods, while the results of the serum and saliva ELISAs revealed 39.39% and 56.95% horses positive for Anoplocephala spp., respectively. Two coprological methods, the mini-FLOTAC and the double centrifugation/ combined sedimentation-flotation technique (Noel et al. 2017;Rehbein et al. 2011) showed similar results in complete agreement with recent German data (Jürgenschellert et al. 2020). Despite the information that the double centrifugation/combined sedimentation-flotation technique is relatively more sensitive compared to other flotation methods (Rehbein et al. 2011), it was difficult to draw a reliable conclusion here due to the low number of positive horses detected by the coprological methods. ...
A lack of accurate information on the prevalence and distribution of Anoplocephala spp. infections on horse farms has led to insufficient attention to tapeworm control and increasing horse anoplocephaloses in Europe. Our study aimed to examine the occurrence of Anoplocephala spp. infection using coprological, serum- and saliva-based antibody detection methods and to analyze the risk factors associated with tapeworm infection in domestic horses in Slovakia. Fecal, serum, and saliva samples were collected from 427 horses from 31 farms in Slovakia. Additionally, a questionnaire study was conducted to collect information on tapeworm distribution on horse farms and analyze risk factors associated with infection. Fecal samples were examined by the mini-FLOTAC and the double centrifugation/combined sedimentation-flotation techniques. Serum and saliva samples were analyzed by ELISA to determine antibody levels against Anoplocephala spp. The effects of variables associated with an individual horse were tested for the positive result of the saliva ELISA test on Anoplocephala spp. Cestode eggs were detected in 1.99% of fecal samples (farm prevalence 12.90%), with no differences between the two coprological methods. Serum-based tapeworm ELISA results revealed that 39.39% of horses tested positive (farm prevalence 83.87%); while saliva-based tapeworm ELISA results revealed 56.95% positive horses (farm prevalence 96.77%). Binary logistic regression analysis revealed four meaningful predictors that significantly impacted the likelihood of detecting tapeworm infection in horses: horse age, pasture size, anthelmintic treatment scheme, and access to pasture. The influences of other variables associated with an individual horse were not significantly associated with detecting tapeworm infection.
... Diagnostic techniques are not perfect. They are inherently subject to systematic and random errors, caused by biological variability and fundamentally intrinsic factors [12,40], such as the detection limits of the technique; execution of protocols; level of analytical training; homogenization and weighing of the sample; ltration of the material; density and volume of the otation solution; the number of replicates analyzed; and even reading time, operator fatigue or motivation [9,13,[49][50][51][52][53]. These errors can be minimized to improve the precision and accuracy of the test under evaluation either by control factors mentioned above or by calibration of the diagnostic devices [18, 19,21,51,54]. ...
... Several studies compared and evaluated mF and MM techniques in the quanti cation of strongyle eggs in equines, using different methodological and statistical approaches [1]: Linear correlation [12]; Student t-test and paired Wilcoxon test [11]; Spearman correlation and paired Wilcoxon test [16]; Tukey's pairwise comparison and linear model analysis [14]; Kruskal-Wallis test, paired Mann-Whitney test and boxplots graph [15]; paired t-test [9,10]; Boxplots and Spearman rank correlation [19]; Linear correlations, t-test, mixed linear model analysis and Tukey's pairwise comparison [21], random coe cient Poisson regression model and negative binomial regression [13]. Some of these statistical analysis present drawbacks in the assessment of concordance as described by . ...
... The intra-variability of MM56-mF45 at different SEL levels (n = 32), indicates that MM56 provides higher SD and CV values, and therefore, offers lower diagnostic accuracy [11]. This observation is reinforced by Noel et al. [12], with differences in SD (4.42; 18.04) and CV (46.3%; 16.8%), for MM56 and mF45 respectively. In contrast, the mF technique offers greater precision and accuracy than MM. ...
Fecal egg counting techniques in horses are useful in the determination of parasitic loads and anthelmintic efficacy; and have been validated in different geographical scenarios with diverse biological samples. However, until now, there has been no consensus among laboratories, due to the use of statistical analyses with methodological and interpretative limitations, with discrepant results of accuracy and precision for McMaster (MM) and mini-FLOTAC (mF) regarding the more accurate. The study of intra-variability between MM and mF at two different fecal dilutions (5:45 and 4:56), using feces from horses naturally infected with strongyle eggs (n= 130), by duplicate readings, showed high repeatability, minimal intra-laboratorial variability, high accuracy, with low coefficient of variation: mF45[2. 92% ± 0.05], mF56[3.43% ± 0.05], MM56[3.46% ± 0.05] and MM45[3.42% ± 0.05; and high concordance correlation coefficient: mF45 0.97 (0.97 - 0.99, 95%-CI), mF56 0.97 (0.96 - 0.98, 95%-CI, MM56 0.90 (0.87 - 0.93, 95%-CI) and MM45 0.93 (0.90 - 0.95, 95%-CI). Bland-Altman inter-variance analysis (n= 1030) with a single reading, between mF56-mF45 demonstrates a high concordance correlation coefficient of 0.90 (0.87 - 0.93, 95%-CI) and low coefficient of variation (5.9% ± 0.09). On the contrary, a low concordance was recorded for MM56-mF56 and MM56-mF45 concordance correlation coefficient 0. 51 (0.49 - 0.53, 95%-CI) and CCC 0.43 (0.41 - 0.45, 95%-CI), respectively; with negative performance related to egg count and a high coefficient of variation (MM56-mF56 13.2% ± 0.20) and MM56-mF45 (CV 15.3% ± 0.24). The Bland-Altman method allows for the graphical and statistical analysis of repeatability and concordance between diagnostic methods, intuitively, with the use of accuracy and precision indicators, being easy to interpret and compare.
... The use of laboratory techniques for helminth egg counting to assess the intestinal parasite load and determine the effectiveness of anthelmintics is common in the field of parasitology, especially in veterinary parasitology. McMaster's classic quantitative technique for the parasitological examination of feces is one of the most widely used in veterinary medicine for this purpose (Noel et al., 2017;Alowanou et al., 2021). However, new quantitative techniques that are more sensitive have been developed, such as FLOTAC and Mini-FLOTAC (Cringoli et al., 2010(Cringoli et al., , 2017. ...
... The Mini-FLOTAC technique, which involves the passive fluctuation of parasitic structures, allows for the simultaneous diagnosis of helminth eggs/larvae and protozoan oocysts/cysts (Cringoli et al., 2017). In general, studies have demonstrated that the Mini-FLOTAC technique offers higher sensitivity and efficiency than the McMaster technique for research of parasites in samples of humans and other animals (Noel et al., 2017;Dias de Castro et al., 2017;Barda et al., 2014;Alowanou et al., 2021). ...
... It is worth mentioning that this is the first study that compares these techniques applied to pig fecal matter in Brazil, and other studies in the literature that analyzed these techniques with pig feces have not been retrieved. The Mini-FLOTAC has also been shown to be superior to McMaster in the diagnosis of helminths in feces of other host species and in the diagnosis of strongyles in horses in the United States, strongyles and Strongyloides in equine and cattle feces in Brazil (Noel et al., 2017;Dias de Castro et al., 2017), Ascaris lumbricoides and Hymenolepis nana in children's feces in Argentina (Barda et al., 2014), and strongyles and other nematodes in sheep, goat and rabbit Table 2. Mean EPG values determined by the two quantitative techniques for the recovery of nematode eggs in feces of pigs raised on family farms. ...
This purpose of this study was to compare the efficiency of the McMaster and Mini-FLOTAC quantitative techniques in the investigation of helminths in feces of pigs. An analysis was made of 74 fecal samples from pigs raised on family farms located in Rio de Janeiro, Brazil. These were analyzed by the Mini-FLOTAC and McMaster techniques in a solution of 1,200g/mL NaCl. This investigation revealed a superiority in the frequency of all helminths detected by Mini-FLOTAC, including Ascaris suum, Trichuris suis, strongyles and Strongyloides ransomi. The Kappa index revealed substantial agreement in all comparisons made in relation to the frequency of positive samples. However, significant statistical differences in the comparison of EPGs between McMaster and Mini-FLOTAC were observed for all nematodes (p ≤0.05). Higher values of Pearson's linear correlation coefficient (r), between the techniques in relation to EPG were observed for A. suum and T. suis, differently from what was observed for strongyles and S. ransomi. Mini-FLOTAC proved to be a more satisfactory and reliable technique both for the diagnosis of parasites and for the determination of EPG in pig feces due to the larger size of its counting chambers, thus increasing the helminth egg recovery rates. Resumo Este estudo objetivou comparar a eficiência das técnicas quantitativas de McMaster e Mini-FLOTAC para a pesquisa de helmintos em fezes de suínos. Foram analisadas 74 amostras fecais de suínos mantidos em propriedades familiares, localizadas no Rio de Janeiro, Brasil. Estas foram analisadas pelas técnicas de Mini-FLOTAC e McMaster com solução de NaCl 1.200g/mL. Pode-se verificar uma superioridade na frequência de todos os helmintos detectados por meio do Mini-FLOTAC, incluindo-se Ascaris suum, Trichuris suis, estrongilídeos e Strongyloides ransomi. O índice Kappa mostrou uma concordância substancial em todas as comparações realizadas, em relação à frequência de amostras positivas. Entretanto, diferenças estatísticas significativas na comparação do OPG entre McMaster e Mini-FLOTAC foram observadas para todos os nematoides (p ≤0.05). Elevados valores do coeficiente de correlação de Pearson foram observados entre as técnicas, em relação ao OPG para A. suum e T. suis, diferentemente do evidenciado para estrôngilos e S. ransomi. Mini-FLOTAC mostrou-se uma técnica mais satisfatória e confiável, tanto para o diagnóstico de parasitos quanto para a determinação do OPG em fezes de Braz J Vet Parasitol 2023; 32(2): e013322 2/6 Diagnosis of pig parasites suínos, devido ao maior tamanho das suas câmaras de contagem, situação que acaba aumentando a eficiência da recuperação dos ovos dos helmintos. Palavras-chave: Diagnóstico parasitológico, técnicas quantitativas, OPG, Nematoide.
... The Mini-FLOTAC technique is a newer technique that utilizes a double chambered disc allowing for a volume of 2 ml to be examined, with an analytical sensitivity of 5 EPG (Cringoli et al., 2017). The Mini-FLOTAC, when used with the recommended homogenizer device called the fill-FLOTAC, has been reported to have higher accuracy, precision and egg recovery compared to the McMaster technique (Noel et al., 2017;Paras et al., 2018). ...
... The McMaster technique has been known to have a lower accuracy and precision when compared to the Mini-FLOTAC technique (Noel, 2017). The standard Mini-FLOTAC protocol when used with the fill-FLOTAC has a sensitivity of 5 EPG (Cringoli et al., 2017). ...
... However, a single replicate of the McMaster technique can be performed relatively quicker than a single replicate of the Mini-FLOTAC (7 min/sample vs 13 min/sample) (Barda et al., 2014). A triplicate count of the McMaster can be performed in approximately 18 min (Noel et al., 2017). ...
Several quantitative diagnostic techniques are available to estimate gastrointestinal parasite counts in the feces of ruminants. Comparing egg and oocyst magnitudes in naturally infected samples has been a recommended approach to rank fecal techniques. In this study, we compared the Mini-FLOTAC (sensitivity of 5 eggs per gram (EPG)/oocysts per gram (OPG)) and different averaged replicates of the modified McMaster techniques (sensitivity of 33.33 EPG/OPG) in 387 fecal samples from 10 herds of naturally infected North American bison in the Central Great Plains region of the USA. Both techniques were performed with fecal slurries homogenized in a fill-FLOTAC device. In the study population, prevalence of strongyle eggs, Eimeria spp. oocysts, Moniezia spp. eggs and Trichuris spp. eggs was 81.4%, 73.9%, 7.5% and 3.1%, respectively. Counts of strongyle eggs and Eimeria spp. oocysts obtained from 1–3 averaged technical replicates of the modified McMaster technique were compared to a single replicate of the Mini-FLOTAC. Correlation between the two techniques increased with an increase in the number of averaged technical replicates of the modified McMaster technique used to calculate EGP/OPG. The correlation for Moniezia spp. EPG when averaged triplicates of the modified McMaster technique were compared to a single replicate of the Mini-FLOTAC count was high; however, the correlation for Trichuris spp. eggs was low. Additionally, we used averaged counts from both techniques to show the overdispersion of parasites in bison herds.
... The techniques precision as described by Noel et al. (2017) was computed as follows: first, a CV (SD divided by the mean count times 100%) was calculated for each set of triplicate counts for each technique for each sample. Mean coefficients of variation with 95% confidence intervals were then calculated for each of the two techniques. ...
... Indeed, in previous work, Cringoli et al. (2017) reported that the Mini-FLOTAC technique permits to sample and homogenize a comparatively larger amount of feces (up to 5 g) and afterwards to directly analyse 200 mg of feces contrary to usual techniques such as Kato-Katz (41.7 mg) of stool, employed in humans and McMaster (66.7 mg of feces) in veterinary practices. In addition, Noel et al. (2017) reported that the McMaster has a volume under the counting grid which is 0.15 ml corresponding to a total of 0.30 ml examined while the Mini-FLOTAC possess 1 ml per chamber, for a total of 2 ml examined. Therefore, the larger volume investigated should help enhance the precision by offering a better representation of eggs present in the samples (Noel et al. 2017). ...
... In addition, Noel et al. (2017) reported that the McMaster has a volume under the counting grid which is 0.15 ml corresponding to a total of 0.30 ml examined while the Mini-FLOTAC possess 1 ml per chamber, for a total of 2 ml examined. Therefore, the larger volume investigated should help enhance the precision by offering a better representation of eggs present in the samples (Noel et al. 2017). Similar outcomes have been highlighted in previous studies using the Mini-FOTAC technique in comparison with the McMaster technique (Rinaldi et al. 2014;Dias de Castro et al. 2017;Noel et al. 2017) or with other techniques such as Kato-Katz technique (Barda et al. 2013b) the FECPAK technique (Godber et al. 2015). ...
... For faecal egg counting techniques, diagnostic sensitivity only has implications for samples with low egg counts. In our validation studies, we have consistently found that samples with counts above 50 EPG are generally always testing positive regardless of which technique was used (Noel et al., 2017;Scare et al., 2017). In samples with lower egg quantities, however, some techniques detected a higher proportion of positive samples than others. ...
... For faecal egg counting techniques, diagnostic sensitivity only has implications for samples with low egg counts. In our validation studies, we have consistently found that samples with counts above 50 EPG are generally always testing positive regardless of which technique was used (Noel et al., 2017;Scare et al., 2017). In samples with lower egg quantities, however, some techniques detected a higher proportion of positive samples than others. ...
... Thus, interpretation of results is largely affected by precision, which should be considered when choosing egg counting technique and interpreting the results. We have found that the most precise faecal egg counting techniques to be performing with coefficients of variation below 20%, whereas less precise techniques can be 50% or higher (Cain et al., 2020;Noel et al., 2017;Scare et al., 2017). Among manual egg counting techniques currently available for equine practitioners, the Mini-FLOTAC technique has been shown to be the most precise (Noel et al., 2017). ...
Widespread occurrence of anthelmintic resistance in ascarid and strongylid parasites has led to recommendations of routine treatment efficacy screening with the faecal egg count reduction test. Furthermore, faecal egg counts are used for classifying mature horses into low, moderate and high strongylid egg shedders, and to monitor for ascarids in foals, weanlings and yearlings. The plethora of egg counting techniques is surrounded by
confusion and misconception regarding their use, diagnostic performance and interpretation. This article aims to explain general concepts of evaluating and assessing faecal egg count test performance and address some of the most common misconceptions. The multiplication factor, which is used to convert the number of eggs counted under the microscope to eggs per gram of faeces, is a theoretically derived number, which does not reflect sensitivity. Accuracy and precision are quantitative
performance parameters, which are not synonymous. Accuracy is a measure of how close a technique measures to the true count, and has implications for the classification
of strongylid egg shedders, but will not affect anthelmintic treatment efficacy evaluation or ascarid monitoring. Precision is a measure of how close repeated counts are to each other, and affects anthelmintic efficacy estimates and strongylid shedding classification. Faecal egg counts do not correlate with worm burdens and do not inform on parasitic
involvement in disease. Techniques using test tubes with cover slips placed on top tend to perform with low accuracy and precision in comparison to techniques using
counting chambers. Veterinarians should consider the performance of the technique employed for determining faecal egg counts, whether they offer these in house or use
a referral diagnostic service. Furthermore, they should consider the training and experience of personnel and protocols in place for diagnostic quality assurance
... The techniques precision as described by Noel et al. (2017) was computed as follows: first, a CV (SD divided by the mean count times 100%) was calculated for each set of triplicate counts for each technique for each sample. Mean coefficients of variation with 95% confidence intervals were then calculated for each of the two techniques. ...
... Indeed, in previous work, Cringoli et al. (2017) reported that the Mini-FLOTAC technique permits to sample and homogenize a comparatively larger amount of feces (up to 5 g) and afterwards to directly analyse 200 mg of feces contrary to usual techniques such as Kato-Katz (41.7 mg) of stool, employed in humans and McMaster (66.7 mg of feces) in veterinary practices. In addition, Noel et al. (2017) reported that the McMaster has a volume under the counting grid which is 0.15 ml corresponding to a total of 0.30 ml examined while the Mini-FLOTAC possess 1 ml per chamber, for a total of 2 ml examined. Therefore, the larger volume investigated should help enhance the precision by offering a better representation of eggs present in the samples (Noel et al. 2017). ...
... In addition, Noel et al. (2017) reported that the McMaster has a volume under the counting grid which is 0.15 ml corresponding to a total of 0.30 ml examined while the Mini-FLOTAC possess 1 ml per chamber, for a total of 2 ml examined. Therefore, the larger volume investigated should help enhance the precision by offering a better representation of eggs present in the samples (Noel et al. 2017). Similar outcomes have been highlighted in previous studies using the Mini-FOTAC technique in comparison with the McMaster technique (Rinaldi et al. 2014;Dias de Castro et al. 2017;Noel et al. 2017) or with other techniques such as Kato-Katz technique (Barda et al. 2013b) the FECPAK technique (Godber et al. 2015). ...
McMaster (McM) method is one of the most widely used techniques for the assessment of faecal parasites shedding in veterinary practices because of its simplicity. However, due to its light sensitivity, recently, the Mini-FLOTAC (MF) has been introduced as a possible alternative for faecal worm egg counts. This study aims to compare the diagnosis performance of MF to McM technique. Faecal samples from 40 animals randomly selected in sheep, goats and rabbits’ farms were collected and examined individually using MF and McM techniques. A statistical difference (p < 0.001) in strongylida egg counts in small ruminants and oocyst of Eimeria spp counts in rabbits using both techniques was observed. However, strongylida eggs per gram of feces in sheep (MF: 202.01 vs McM: 174.75) goat (MF: 147.36 vs McM: 143.75) and oocysts of Eimeria spp per gram of feces in rabbits (MF: 130.75 vs McM: 130.5) revealed no significant difference (p > 0.05). MF showed better diagnostic performance in term of the prevalence (MF: 32.5–100% vs McM: 7.5–70%) and the precision values (MF: 85.52–90.44% vs McM: 49.52–63.07%). This study demonstrated that MF appears to be the more reliable alternative technique for veterinary practices.
... All faecal egg counting was done at the University of Kentucky's Maxwell H. Gluck Equine Research Center using the Mini-FLOTAC method of egg suspension and collection, with a multiplication factor of 5 and glucose-NaCl solution as the flotation medium at 1.24-1.26 specific gravity (Noel et al., 2017). ...
... Although the Mini-FLOTAC egg counting technique employed herein is demonstrated to perform with high accuracy and precision for equine strongylid egg counts (Noel et al., 2017), it should be acknowledged that it has not been validated for detection of anoplocephalid eggs. However, the diagnostic sensitivity of faecal egg counting techniques is generally low for detecting equine tapeworm eggs (Gawor, 1995;Gundlach et al., 2003;Hreinsdóttir et al., 2019;Meana et al., 1998;Proudman & Edwards, 1992;Tomczuk et al., 2014), this is less of a concern when testing for evidence of tapeworm clearance following anthelmintic treatment. ...
Background: Equine anoplocephalid cestodes are tapeworms that occur worldwide in horses and are known to cause pathological manifestations and clinical disease within the digestive system of horses.
Objective: While these clinical manifestations and the efficacy of currently available anthelmintics against equine tapeworms have been well documented, a recent study has demonstrated treatment failure of praziquantel and pyrantel pamoate, suggesting resistance; however, this has not been heavily investigated.
Study design: This case study examined 24 Thoroughbred yearlings on one Kentucky Thoroughbred horse farm to investigate the elimination of tapeworm eggs after administration of routine anticestodal anthelmintics after confirmation of positive faecal egg counts.
Methods: The Mini-FLOTAC faecal egg counting method was used to count anoplocephalid eggs in yearlings treated with pyrantel pamoate paste (13.2 mg base/kg), moxidectin-praziquantel (0.4 and 2.5 mg/kg) and ivermectin-praziquantel
(0.2 and 1 mg/ kg) over a 6-month period in 2022.
Results: Data demonstrated that tapeworm egg shedding persisted post-deworming
with all three anthelmintic products. Out of the 24 Thoroughbred enrolled, 11/24 (45.8%) had persistent infections in the month of March and 3/24 (12.5%) had persistent infections in April after deworming with ivermectin-praziquantel.
With moxidectin-praziquantel, 2/24 (8.3%) remained egg count positive. For pyrantel pamoate, 3/24 (12.5%) were detected with tapeworm eggs post-treatment. During July and August, selected yearlings had faecal sampling done before and 2 weeks post-deworming with moxidectin-praziquantel. For July 1/6 (16.7%) horses had tapeworm eggs both before and after deworming, and one additional horse was positive in the post-treatment sample only. For the August treatment, 4/14 (28.6%) were egg count positive both before and after deworming, with one additional horse being positive in the post-treatment sample only.
Conclusions: This study demonstrated evidence of anthelmintic treatment failure against equine tapeworms by means of regular faecal egg count monitoring. Veterinarians should be aware of this development and implement strategies to monitor anticestodal treatment success.
... This agrees with a previous study by Elghryani et al. [51], where the prevalence of strongyle infections in horses on Irish farms was 52.40% based on samples from 2700 horses between 2015 to 2021. This observation is also in agreement with international studies reporting a high prevalence of equine strongyles in Europe, the USA, and African countries [33,44,[52][53][54]. ...
... In practice this means that slightly more animals would likely be treated (2.3%) based on the 200 epg threshold when testing by OCT compared to MF, although it is worth noting that the Sp estimates for both tests were quite high, 0.962 and 0.985 for MF and OCT, respectively, and is unlikely to be of any clinical significance. Our finding of higher Se of MF than MCM for detecting the GIH is in agreement with existing studies [33,44,[52][53][54], and is likely due to the differences in detection limits between the techniques, where the minimum detection limit is 7.5 epg with the MF compared to 50 epg with the MCM. Taken together, these findings suggest that OCT is at least as accurate as existing reference techniques for detection and enumeration of strongyle eggs in equines. ...
Simple Summary
The faecal examination test is commonly employed for the identification and counting of parasite eggs in faecal samples. In this study, the OvaCyte Telenostic analyser (OCT) was used for detecting and counting helminth parasites in equine and compared with the McMaster and Mini-FLOTAC techniques. The prevalence of strongyle-type eggs was the highest of the detected helminth parasites. There was a strong correlation and agreement between the OCT and the other two counting techniques in this study. In terms of measuring the sensitivity and specificity, the OCT had the highest sensitivity for the detection of strongyles, Parascaris spp., and Anoplocephala spp., compared to the other two techniques.
Abstract
Gastrointestinal helminth parasites continue to be a significant threat to the health of equine. OvaCyte Telenostic (OCT) (Telenostic Ltd., Kilkenny, Ireland) has developed an automated digital microscope utilising Artificial Intelligence to identify and count the clinically important helminth species in equine, bovine, and ovine host species. In this paper, the performance of the OCT analyser was evaluated for the detection and counting of equine helminth species parasites and its performance compared to the currently accepted benchmark methods of faecal egg counts being the McMaster and the Mini-FLOTAC techniques. A pairwise comparison of tests was assessed based on the correlation of egg counts and Cohen’s kappa agreement statistics for dichotomized outcomes. Bayesian latent class analysis was used to estimate the sensitivity and specificity of all three techniques in the absence of a gold standard for four helminth parasites (strongyles, Anoplocephala spp., Parascaris spp. and Strongyloides westeri). Based on the analysis of 783 equine faecal samples, we found a high level (ρ ≥ 0.94) of correlation between each pairwise comparison of techniques for strongyle egg counts. Cohen’s kappa agreement between techniques was high for strongyles and S. westeri, moderate for Parascaris spp., and low for Anoplocephala spp. All three techniques had a high sensitivity and specificity (>0.90) for strongyles. Across helminth parasites, the sensitivity of the OCT was the highest of the three techniques evaluated for strongyles (0.98 v 0.96 and 0.94), Anoplocephala spp. (0.86 v 0.44 and 0.46) and Parascaris spp. (0.96 v 0.83 and 0.96); but lowest for S. westeri (0.74 v 0.88 and 0.88), compared to McMaster and Mini-FLOTAC, respectively. In terms of specificity, OCT was the lowest in two species (Parascaris spp. 0.96, Anoplocephala spp. 0.95). In conclusion, OCT has a sensitivity and specificity statistically similar to both McMaster and Mini-FLOTAC, and had a higher correlation with Mini-FLOTAC. The OCT point of care faecal analyser offers improved workflow, test turn-around time and does not require trained laboratory personnel to operate or interpret the results
... Alternative names for this factor are conversion factor and detection limit [31]. However, routinely used protocols are applied with multiplication factors of 25-50, which is achieved by counting two to four counting fields per sample [18,32]. The FLOTAC [29,33] and Mini-FLOTAC [34][35][36][37] procedures represent improvements of the McMaster approach, and both use mechanical separation of floated eggs from debris below by rotating the upper part of the device by 90°. ...
... egg is found [11,22,57]. In contrast, for a faecal egg count reduction test (FECRT) to identify drug-resistant nematode populations, a sensitive and precise quantitative method is required, and the Mini-FLOTAC method has been repeatedly shown to perform very well in FECRT studies [63][64][65], including studies on horses [32,[66][67][68]. Reasons to consider when choosing a test based on convenience include access to the laboratories that offer tests and acceptable turnaround times for results. ...
Background
Due to high prevalence of anthelmintic resistance in equine helminths, selective treatment is increasingly promoted and in some countries a positive infection diagnosis is mandatory before treatment. Selective treatment is typically recommended when the number of worm eggs per gram faeces (epg) exceeds a particular threshold. In the present study we compared the semi-quantitative sedimentation/flotation method with the quantitative methods Mini-FLOTAC and FECPAK G2 in terms of precision, sensitivity, inter-rater reliability and correlation of worm egg counts to improve the choice of optimal diagnostic tools.
Methods
Using sedimentation/flotation (counting raw egg numbers up to 200), we investigated 1067 horse faecal samples using a modified Mini-FLOTAC approach (multiplication factor of 5 to calculate epgs from raw egg counts) and FECPAK G2 (multiplication factor of 45).
Results
Five independent analyses of the same faecal sample with all three methods revealed that variance was highest for the sedimentation/flotation method while there were no significant differences between methods regarding the coefficient of variance. Sedimentation/flotation detected the highest number of samples positive for strongyle and Parascaris spp. eggs, followed by Mini-FLOTAC and FECPAK G2 . Regarding Anoplocephalidae, no significant difference in frequency of positive samples was observed between Mini-FLOTAC and sedimentation/flotation. Cohen’s κ values comparing individual methods with the combined result of all three methods revealed almost perfect agreement (κ ≥ 0.94) for sedimentation/flotation and strong agreement for Mini-FLOTAC (κ ≥ 0.83) for strongyles and Parascaris spp. For FECPAK G2 , moderate and weak agreements were found for the detection of strongyle (κ = 0.62) and Parascaris (κ = 0.51) eggs, respectively. Despite higher sensitivity, the Mini-FLOTAC mean epg was significantly lower than that with FECPAK G2 due to samples with > 200 raw egg counts by sedimentation/flotation, while in samples with lower egg shedding epgs were higher with Mini-FLOTAC than with FECPAK G2 .
Conclusions
For the simple detection of parasite eggs, for example, to treat foals infected with Parascaris spp., sedimentation/flotation is sufficient and more sensitive than the other two quantitative investigared in this study. Mini-FLOTAC is predicted to deliver more precise results in faecal egg count reduction tests due to higher raw egg counts. Finally, to identify animals with a strongyle epg above a certain threshold for treatment, FECPAK G2 delivered results comparable to Mini-FLOTAC.
Grpahical Abstract
... Alowanou et al. (2021) However, the results obtained with GW technique varied widely and showed large standard deviations. Several studies reported that the GW technique produced significantly larger standard deviations than the MF in different laboratories (Castro et al., 2017;Noel et al., 2017;Alowanou et al., 2021). Both Castro et al. (2017) and Noel et al. (2017) suggested that this difference in the range of variation is probably due to the fact that the multiplication factor applied to the EPG by the GW techniques is 5 to 10 times higher than that employed in the MF. ...
... Several studies reported that the GW technique produced significantly larger standard deviations than the MF in different laboratories (Castro et al., 2017;Noel et al., 2017;Alowanou et al., 2021). Both Castro et al. (2017) and Noel et al. (2017) suggested that this difference in the range of variation is probably due to the fact that the multiplication factor applied to the EPG by the GW techniques is 5 to 10 times higher than that employed in the MF. This difference in the range of variation may mean that the MF is more sensitive and accurate than the GW, but reading takes longer because the MF counting chamber is larger. ...
... Fecal samples were collected from the ground in clean stalls, placed in a plastic bag, sealed, and stored in a refrigerator at 4°C. Fecal samples were screened in triplicate using Mini-FLOTAC (Noel et al. 2017) to determine strongyle egg level and subsequently separated into negative (no eggs seen), 1-200 EPG, 201-500 EPG, 501-1000 EPG, and 1001+ EPG categories ). These levels were used throughout the study. ...
... They were shown a series of 50 microscopy images of various parasite eggs, pollen, air bubbles, and debris and given instruction on how to tell the difference between all of those items. Afterwards, they performed a series of 20 FECs, four at each of the previously described levels, using the Mini-FLOTAC method (Noel et al., 2017). An experienced analyst counted the slide along with the analysts in training, and in order to pass the training, analysts had to be within a ±10% range for all counts above 201 EPG, within ±1 egg counted for the 1-200 EPG range, and all negative counts had to be negative. ...
Fecal egg counts (FECs) are essential for veterinary parasite control programs. Recent advances led to the creation of an automated FEC system that performs with increased precision and reduces the need for training of analysts. However, the variability contributed by analysts has not been quantified for FEC methods, nor has the impact of training on analyst performance been quantified. In this study, three untrained analysts performed FECs on the same slides using the modified McMaster (MM), modified Wisconsin (MW), and the automated system with two different algorithms: particle shape analysis (PSA) and machine learning (ML). Samples were screened and separated into negative (no strongylid eggs seen), 1–200 eggs per gram of feces (EPG), 201–500 EPG, 501–1000 EPG, and 1001+ EPG levels, and ten repeated counts were performed for each level and method. Analysts were then formally trained and repeated the study protocol. Between analyst variability (BV), analyst precision (AP), and the proportion of variance contributed by analysts were calculated. Total BV was significantly lower for MM post-training (p = 0.0105). Additionally, AP variability and analyst variance both tended to decrease for the manual MM and MW methods. Overall, MM had the lowest BV both pre- and post-training, although PSA and ML were minimally affected by analyst training. This research illustrates not only how the automated methods could be useful when formal training is unavailable but also how impactful formal training is for traditional manual FEC methods.
... 15 These methods either require specialised equipment or a subscription for the acquisition of results. Multiple studies have compared the precision, accuracy and sensitivity of these methods, [16][17][18] and these are variables that are important for researchers and practitioners to consider. For monitoring egg-shedding on horse properties, the preference for the FEC method by equine veterinarians will likely depend on the number of samples routinely processed. ...
Over the past few decades, the emergence of resistance amongst intestinal parasites of horses to all available anthelmintic classes has emphasised the need for a paradigm shift in parasite control approaches within the Australian equine industry. Findings of a recent Australia‐wide research project have provided new insights into intestinal parasites (i.e. strongyles and ascarids) and parasite control from the perspectives of Australian horse breeders and equine veterinarians. The published data have revealed recent trends in parasite prevalence and distribution, breeders' and veterinarians' attitudes and perspectives on controlling horse internal parasites, the efficacy of commonly used anthelmintic products and post‐treatment egg reappearance periods. These studies have formed the basis of newly developed guidelines managing and treating gastrointestinal nematodes in horses. Tailored for equine veterinarians, these guidelines contain information on target parasites and risk factors for their transmission, as well as practical advice for surveillance, anthelmintic choice, timing of treatment, testing for anthelmintic resistance and managing refugia. The Australian Guidelines for Equine Internal Parasite Management (AGEIPM) will serve as a pocket companion for equine veterinarians, providing best‐practice recommendations grounded in locally conducted scientific research. Dissemination and extension of the AGEIPM to industry will strengthen the client–practitioner relationship. The aim is to reduce reliance on blanket deworming in equine parasite management programs and help curb the progression of resistance to the limited anthelmintic classes available for treating horses.
... Although the time required to conduct the faecal analysis of the samples using the two quantitative methods was not recorded in the present study, previous studies comparing the McMaster and Mini-FLOTAC methods have established that the Mini-FLOTAC procedure requires significantly longer hands-on time (13 min per sample) compared with the McMaster method (7 min per sample) [48,51,64]. ...
Background
Faecal egg counts (FECs) are essential for diagnosing helminth infections and guiding treatment decisions. For camels, no evaluations of coproscopic methods regarding precision, sensitivity and correlation between individual and pooled faecal samples are currently available.
Methods
Here, 410 camel faecal samples were collected in 2022 from South Darfur State, Sudan, and analysed to compare the semi-quantitative flotation, McMaster and Mini-FLOTAC methods in terms of precision, sensitivity, inter-rater reliability and helminth egg count correlations, as well as the effects of pooling samples. Six samples were used to assess precision for McMaster and Mini-FLOTAC, while the remaining 404 samples were evaluated for sensitivity, inter-rater reliability and egg count correlations. Of these, 80 samples were used in pooling experiments.
Results
Six analyses of each sample (n = 6) using the McMaster and Mini-FLOTAC methods revealed no significant difference in the coefficient of variation between the two. For strongyle eggs, 48.8%, 52.7% and 68.6% were positive for McMaster, semi-quantitative flotation and Mini-FLOTAC, respectively. The sensitivity of the three methods showed only minimal improvement when three egg counts were performed on the same sample. McMaster and Mini-FLOTAC had similar sensitivity for Strongyloides spp. (3.5% frequency), while it was lower for semi-quantitative flotation at 2.5%. Mini-FLOTAC was more sensitive for Moniezia spp., detecting 7.7% of positives compared with 4.5% for semi-quantitative flotation and 2.2% for McMaster. For Trichuris spp., frequencies were 0.3% with Mini-FLOTAC, 0.7% with McMaster and 1.7% with semi-quantitative flotation. Mini-FLOTAC also detected higher strongyle eggs per gram (EPG) of faeces (mean 537.4) compared with McMaster (330.1). More samples exceeded treatment thresholds with Mini-FLOTAC, with 28.5% of animals having EPG ≥ 200 compared with 19.3% for McMaster, while 19.1% showed EPG ≥ 500 with Mini-FLOTAC compared with 12.1% with McMaster. There was no significant correlation between individual and pooled strongyle FECs, as indicated by Pearson correlation coefficients of r ≥ 0.368 (P ≥ 0.113) and Spearman correlation.
Conclusions
Mini-FLOTAC outperformed semi-quantitative flotation and McMaster in diagnosing helminth infections in camels, offering greater sensitivity and detecting higher EPGs, particularly for strongyles, Strongyloides spp. and Moniezia spp. Thus, treatment decisions based on Mini-FLOTAC EPGs will lead to more treatments.
Graphical Abstract
... The performances of the two automated methods (Parasight AIO and Imagyst) were compared to that of mini-FLOTAC, a widely accepted research method that has been the subject of a large number of validations and comparative studies [2,[21][22][23][32][33][34][35][36][37][38][39]. ...
Background
Digital imaging combined with deep-learning-based computational image analysis is a growing area in medical diagnostics, including parasitology, where a number of automated analytical devices have been developed and are available for use in clinical practice.
Methods
The performance of Parasight All-in-One (AIO), a second-generation device, was evaluated by comparing it to a well-accepted research method (mini-FLOTAC) and to another commercially available test (Imagyst). Fifty-nine canine and feline infected fecal specimens were quantitatively analyzed by all three methods. Since some samples were positive for more than one parasite, the dataset consisted of 48 specimens positive for Ancylostoma spp., 13 for Toxocara spp. and 23 for Trichuris spp.
Results
The magnitude of Parasight AIO counts correlated well with those of mini-FLOTAC but not with those of Imagyst. Parasight AIO counted approximately 3.5-fold more ova of Ancylostoma spp. and Trichuris spp. and 4.6-fold more ova of Toxocara spp. than the mini-FLOTAC, and counted 27.9-, 17.1- and 10.2-fold more of these same ova than Imagyst, respectively. These differences translated into differences between the test sensitivities at low egg count levels (< 50 eggs/g), with Parasight AIO > mini-FLOTAC > Imagyst. At higher egg counts Parasight AIO and mini-FLOTAC performed with comparable precision (which was significantly higher that than Imagyst), whereas at lower counts (> 30 eggs/g) Parasight was more precise than both mini-FLOTAC and Imagyst, while the latter two methods did not significantly differ from each other.
Conclusions
In general, Parasight AIO analyses were both more precise and sensitive than mini-FLOTAC and Imagyst and quantitatively correlated well with mini-FLOTAC. While Parasight AIO produced lower raw counts in eggs-per-gram than mini-FLOTAC, these could be corrected using the data generated from these correlations.
Graphical Abstract
... A previous study suggested that the Cornell-Wisconsin technique may be just as sensitive as Proudman and Edwards (Slocombe, 2004), however, no studies have compared these two techniques side by side. Furthermore, the Mini-FLOTAC technique is a refined version of McMaster with better sensitivity, accuracy, and precision for detection of strongylid eggs (Noel et al., 2017), but the performance of this technique for tapeworm egg counting has not been evaluated so far. ...
Tapeworm infection in horses can cause serious health concerns, and recent data have documented treatment failures in the most common species, Anoplocephala perfoliata. The threat of anthelmintic resistance in A. perfoliata is of particular concern because of poor diagnostic performance of standard egg counting techniques for detecting this parasite. This study compared the performance of three diagnostic techniques 1) Mini-FLOTAC, 2) Cornell-Wisconsin, and 3) Proudman and Edwards used to detect and quantify A. perfoliata eggs in naturally infected horses. Eighteen adult female horses from the University of Kentucky’s historic parasitology herd were included in this study. Fecal samples were collected from all horses at five collection time points two weeks apart and analyzed with the three techniques. A total of 90 samples were collected and 270 counts determined in the study. The proportions of positive samples determined by the three techniques were significantly different from each other (p<0.05): Mini-FLOTAC (16%), Cornell-Wisconsin (47%), and Proudman and Edwards (70%). The Proudman and Edwards technique counted consistently higher numbers of tapeworm eggs compared to the other two techniques throughout the study [p < 0.05]. Total raw counts of tapeworm eggs across the study for each technique were 16, 88, and 410 for the Mini-FLOTAC, Cornell-Wisconsin, and Proudman and Edwards, respectively. This study demonstrated that the Proudman and Edwards technique was superior in diagnosing A. perfoliata infection. Future work needs to assess this technique’s potential for Fecal Egg Count Reduction Testing (FECRT).
... Initial validation to assess beads' compatibility with horse fecal matrix and their ability to float in various floatation solutions of differing SPG proved their usefulness for such a study. One major hurdle was aliquoting the desired number of beads via manual titrations as performed in prior studies using strongyle eggs [26,27]. However, bead sorting through the large object flow cytometer (BioSorter) obtained aliquots of appropriate concentrations needed. ...
The American Association of Equine Practitioners strongly advocates evidence-based intestinal strongyle control in horses. It recommends targeted treatment of all heavy egg shedders (>500 eggs per gram (EPG) of feces), while the low shedders (0–200 EPG) are left untreated. As 50–75% of adult horses in a herd are low shedders, preventing them from unnecessary anthelmintic exposure is critical for tackling resistance. There are various fecal egg count (FEC) techniques with many modifications and variations in use, but none is identified as a gold standard. The hypothesis of the study was that the diagnostic performance of 12 commonly used quantitation methodologies (three techniques with four variants) differs. In this regard, method comparison studies were performed using polystyrene beads as proxy for intestinal strongyle eggs. Mini-FLOTAC-based variants had the lowest coefficient of variation (CV%) in bead recovery, whereas McMaster variants had the highest. All four variants of Mini-FLOTAC and the NaNO3 1.33 specific gravity variant of modified Wisconsin followed a linear fit with R² > 0.95. In contrast, the bead standard replicates for modified McMaster variants dispersed from the regression curve, causing a lower R². The Mini-FLOTAC method seems less influenced by the choice of floatation solution and has better repeatability parameters and linearity for bead standard recovery. For FEC tests with high R² (>0.95) but that underestimated the true bead count, a correction factor (CF) was determined to estimate the true count. Finally, the validity of CF was analyzed for 5 tests with R² > 0.95 to accurately quantify intestinal strongyle eggs from 40 different horses. Overall, this study identified FEC methodologies with the highest diagnostic performance. The limitations in standardizing routine FEC tests are highlighted, and the importance of equalization of FEC results is emphasized for promoting uniformity in the implementation of parasite control guidelines.
... Conducting FECs on a 10% subsample of heifers in this study allowed sufficient sampling for a robust analysis while minimizing animal handling, associated stress (e.g., time in chute) and subsequent shrink (Coffey et al., 2001;Barnes et al., 2017). Additionally, FEC counts were carried out using the Mini-FLOTAC technique, which is known to be sensitive, accurate, and precise (Cringoli et al., 2017;Noel, 2017;Amadesi et al., 2020). ...
... Precision of egg counting techniques is important, particularly when conducting fecal egg count reduction tests (FECRTs) to diagnose anthelmintic resistance . Many studies have shown that considerable variation occurs between different strongylid FEC techniques (Slusarewicz et al., 2016;de Castro et al., 2017;Noel et al., 2017;Scare et al. 2017;Bosco et al., 2018;Cain et al., 2020). However, the only known study to evaluate different techniques for ascarid FECs is Napravnikova et al. (2019), who reported precision metrics for the Simple McMaster technique and Concentrated McMaster technique for both strongylid and ascarid egg counts. ...
... Samples were collected rectally and transported in coolers to the laboratory, where they were refrigerated at 4 C and analysed within 5 working days. Strongylid fecal egg counts were determined in triplicate using the Mini-FLOTAC technique (Noel et al., 2017) with a glucose-NaCl solution (specific gravity of 1.26) as flotation medium. The multiplication factor for converting the number of eggs counted to eggs per gram of feces was 5. ...
Macrocyclic lactones (MLs) have been the most widely used drugs for equine parasite control during the past four decades. Unlike ivermectin, moxidectin exhibits efficacy against encysted cyathostomin larvae, and is reported to have persistent efficacy with substantially longer egg reappearance periods (ERPs). However, shortened ERPs have been reported recently for both MLs, and these findings have raised several questions: (i) are ERP patterns different after ivermectin or moxidectin treatment? (ii) Are shortened ERPs associated with certain cyathostomin species or stages? (iii) How does moxidectin's larvicidal efficacy affect ERP? To address these questions, 36 horses at pasture, aged 2-5 years old, were randomly allocated to three treatment groups: 1, moxidectin; 2, ivermectin; and 3, untreated control. Strongylid fecal egg counts were measured on a weekly basis, and the ERP was 5 weeks for both compounds. Strongylid worm counts were determined for all horses: 18 were necropsied at 2 weeks post-treatment (PT), and the remaining 18 at 5 weeks PT. Worms were identified to species morphologically and by internal transcribed spacer-2 (ITS-2) rDNA metabarcoding. Moxidectin and ivermectin were 99.9% and 99.7% efficacious against adults at 2 weeks post treatment, whereas the respective efficacies against luminal L4s were 84.3% and 69.7%. At 5 weeks PT, adulticidal efficacy was 88.3% and 57.6% for moxidectin and ivermectin, respectively, while the efficacy against luminal L4s was 0% for both drugs. Moxidectin reduced early L3 counts by 18.1% and 8.0% at 2 or 5 weeks, while the efficacies against late L3s and mucosal L4s were 60.4% and 21.2% at the same intervals, respectively. The luminal L4s surviving ivermectin treatment were predominantly Cylicocyclus (Cyc.) insigne. The ITS-2 rDNA metabarcoding was in good agreement with morphologic species estimates but suggested differential activity between moxidectin and ivermectin for several species, most notably Cyc. insigne and Cylicocyclus nassatus. This study was a comprehensive investigation of current ML efficacy patterns and provided important insight into potential mechanisms behind shortened ERPs.
... The higher sensitivity of Mini-FLOTAC compared with the McMaster method for all the detected parasites is in line with the known sensitivity of the former method, i.e., 5 eggs per gram of feces (epg)/larvae per gram of feces (lpg)/oocysts per gram of feces (opg)/cysts per gram of feces (cpg) [1], compared to the ranges between 50 and 100 epg/lpg/opg/cpg known for the latter [6]. In agreement with the present results, previous studies have already shown that the Mini-FLOTAC has higher sensitivity and accuracy than the McMaster in the diagnosis of parasitic diseases in dogs and cats as well as other animals (e.g., goats, equines) [1,7,[18][19][20]. ...
Simple Summary
Appropriate fecal examinations are very important for diagnosing parasitic diseases in dogs and cats. In this study, four different conventional copromicroscopic techniques (flotation, McMaster, Mini-FLOTAC, and Baermann) were evaluated for their performance in detecting intestinal and extra-intestinal parasitic elements in canine and feline feces. Stool samples from 100 dogs and 105 cats, respectively, were tested with the above techniques. Flotation and Mini-FLOTAC gave the best results in detecting intestinal and respiratory parasitoses by Toxocara spp., Toxascaris leonina, Ancylostomatidae, Cystoisospora spp., Trichuris vulpis and Capillaria spp., whereas the Baermann test was the best method for the detection of infections caused by metastrongyloids. These data provide useful information for veterinary clinicians on the most appropriate techniques to use during diagnostic paths in clinical settings.
Abstract
Several copromicroscopic techniques, including tools belonging to the FLOTAC group, are available for the qualitative and/or quantitative diagnosis of canine and feline parasitoses. The present study was carried out to compare the diagnostic performance of different copromicroscopic methods for detecting common intestinal and extra-intestinal parasites of dogs and cats. Fecal samples of 100 dogs and 105 cats were randomly selected from different regions of Italy. All samples were subjected to conventional flotation, McMaster, Mini-FLOTAC, and Baermann. Fifty-six dogs and twenty-five cats were found positive to at least one technique, and, among them, flotation (55% and 20.9% of the dogs and cats, respectively) and Mini-FLOTAC (52% and 20.9% of the dogs and cats, respectively) detected the highest number of positive samples. Larvae of the feline metastrongyloids Aelurostrongylus abstrusus and Troglostrongylus brevior were identified only using the Baermann test in two (1.9%) and one (0.9%) cat respectively. No larvae were found with the Baermann examination of dog feces or any of the other methods. The present results show that the Mini-FLOTAC represents a possible alternative to conventional flotation in clinical settings for the detection of intestinal and respiratory parasites e.g., Toxocara spp., Toxascaris leonina, Ancylostomatidae, Cystoisospora spp., Trichuris vulpis and Capillaria spp., although Baermann’s test remains the most recommended technique for the diagnosis of infections caused by metastrongyloid lungworms.
... Two foals naturally infected with Parascaris spp. were identified based on fecal egg counts determined by the Mini-FLOTAC technique (45). The timing of weekly fecal egg counts is provided in the figure. ...
Bacillus thuringiensis crystal proteins are widely and safely used as insecticides. Recent studies have shown they also can cure gastrointestinal parasitic worm (nematode) infections when ingested.
... Mini-FLOTAC (University of Naples Federico II, FLOTAC R Group, Naples, Italy) counting chambers (86,87) were used to determine FEC by processing a 5 g faecal sample with the Fill-FLOTAC device (University of Naples Federico II, FLOTAC R Group, Naples, Italy), as previously described by Noel et al. (88), with 45 ml of saturated saline solution (specific gravity 1.2) being added. In addition, a double centrifugation/combination sedimentation flotation method was used according to the technique published by Rehbein et al. (89). ...
The infection of horses with strongylid nematodes is highly prevalent, with multi-species infections being the rule. Strongylus spp. and in particular Strongylus vulgaris are amongst the most pathogenic strongyle equine parasites. Presumably due to regular strategic anthelmintic treatments in combination with long prepatencies, prevalence of these worms was severely reduced in past decades. In this study, 484 horses from 48 farms in Berlin/Brandenburg, Germany were sampled between May 2017 and January 2018. Mini-FLOTAC and combined sedimentation/flotation were used to analyse faecal samples and larval cultures were carried out from individual strongyle infected horses for molecular testing for Strongylus spp. infection. Additionally, for Strongylus vulgaris, antibodies against a recombinant larval antigen were quantified in an ELISA. Strongyle type eggs were detected in 66.7% of the individual faecal samples. Nematode DNA was amplifiable from 311 samples and S. vulgaris and Strongylus edentatus were detected in four (1.3%) and 10 (6.3%) of these, respectively, the latter using a novel high-resolution-melt PCR targeting S. edentatus, Strongylus equinus, and Strongylus asini. On the farm level, prevalence for Strongylus spp. by PCR was 12.5%. Applying a conservative cut-off (sensitivity 0.43, specificity 0.96), 21.2% of all serum samples were positive for antibodies against S. vulgaris larvae (83.3% prevalence on farm level). Newly developed pyrosequencing assays to analyse putatively benzimidazole resistance associated polymorphisms in codons 167, 198, and 200 of the isotype 1 β-tubulin gene of S. vulgaris did not detect such polymorphisms in the four positive samples. Low age and increasing access to pasture were risk factors for egg shedding and seropositivity for S. vulgaris. Time since last treatment increased whereas use of moxidectin and ivermectin for the last treatment decreased the risk for strongyle egg shedding. Noteworthy, horses under selective treatment had significantly higher odds to be seropositive for anti-S. vulgaris antibodies than horses treated four times per year (odds ratio 4.4). The serological findings suggest that exposure to S. vulgaris is considerably higher than expected from direct diagnostic approaches. One potential explanation is the contamination of the environment by a few infected horses, leading to the infection of many horses with larvae that never reach maturity due to regular anthelmintic treatments.
... Together, these results clearly show in resource-limited laboratories, and it has been shown that both techniques have more sensitivity than McMaster. [24][25][26][27] It is unfortunate that this study did not include the aforementioned diagnostic methods because they were not available in our laboratory at the time of this study. A natural progression of this work is to compare different diagnostic methods that can be utilised for the assessment of roundworm infection in poultry. ...
Background:
Ascaridia galli is a widespread problem in cage-free egg production. Sustainable control of nematode infections is a key component in this sector. This study investigates the effect of a treatment strategy against A. galli, aiming to propose a guideline for anthelmintic use on commercial poultry farms.
Methods:
A total of eight flocks of laying hens (a-h) from five commercial poultry farms were included in this study. Faecal samples were collected on a biweekly basis starting at 7-13 weeks post-placement (WPP) and processed using the McMaster method to calculate ascarid egg shedding. Flocks were treated after the threshold of 200 eggs per gram of faeces (EPG) was reached.
Results:
The highest initial faecal egg count was 6700 EPG at 11 WPP, whereas the lowest was 50 at 8 WPP. The longest delay to detect A. galli was 7 weeks. The lowest and the highest number of treatments were four and six, respectively. The shortest and longest periods between any two treatments were 5 and 22 weeks, respectively.
Conclusions:
These results suggest that monitoring for A. galli should start at approximately 7 WPP and should be repeated every 8 weeks until hens are 50 weeks old. Treatment should be given only if moderate to high faecal egg counts are observed. Treatments after this point may be repeated every 8 weeks without eventually performing a faecal test. These findings provide practical support to veterinarians and egg producers dealing with ascarid worm infection in laying hens in their production stage.
... In general, use of egg counting techniques for which accuracy and precision have been determined and validated in equines is recommended. See Noel et al. (2017) for examples of how these can be determined. As a general guidance, techniques performing with a coefficient of variation (CV) of 20% or less are considered high precision techniques and would be recommended for this type of study. ...
This guideline have been developed to assist in the design, execution, and interpretation of studies to assess the efficacy of anthelmintic drugs against internal parasites of equines, including nematodes, cestodes, and larval instars of Gasterophilus spp. The design and execution of critical and controlled studies are outlined, and their advantages and disadvantages are discussed. Unique considerations for specific target parasites are included. Information is also provided on selection of animals, procedures for randomization, housing, feeding, dosage titration, dosage confirmation and field studies, record keeping and necropsy procedures. Finally, this document includes guidance for group size determination and statistical analysis of study results. This guideline should assist investigators in the evaluation of anthelmintic drugs in horses by using comparable and standardized procedures in studies with appropriate numbers of animals.
... FECs were determined in triplicate using the Mini-FLO-TAC method as described previously [31], using a saturated glucose-NaCl flotation medium (specific gravity of 1.25) and with a multiplication factor of five eggs per gram (EPG). Specimens were evaluated for strongylid, Parascaris spp., and S. westeri type eggs. ...
Background
Horses are host to a plethora of parasites. Knowledge of the seasonality of parasite egg shedding and transmission is important for constructing parasite control programs. However, studies describing these patterns are sparse, and have largely been conducted only in the United Kingdom. This study evaluated strongylid egg shedding patterns and transmission dynamics of Strongylus vulgaris in naturally infected and untreated mares and foals through one calendar year in Kentucky, USA. The study also investigated the existence of a peri-parturient rise (PPR) in strongylid egg counts in foaling mares and collected information about Strongyloides westeri and Parascaris spp. in the foals.
Methods
This study was conducted from January to December 2018. A herd of 18 mares, one stallion, and 14 foals born in 2018 were followed throughout the year. Sera and feces were collected biweekly from all horses, and worm burdens enumerated in 13 foals at necropsy. An S. vulgaris ELISA antibody test was run on all serum samples. Fecal egg counts were determined for all horses, and coproculture and qPCR assay were employed to test for the presence of S. vulgaris in the mature horses. Data were analyzed using the proc glimmix procedure in the SAS 9.4 software program.
Results
We found a general lack of seasonality in strongylid egg shedding throughout the year among the mature horses, and no PPR was demonstrated. Shedding of S. vulgaris eggs displayed a higher abundance during the spring, but findings were variable and not statistically significant. Anti- S. vulgaris antibody concentrations did not display significant fluctuations in the mature horses, but evidence of passive transfer of antibodies to the foals was demonstrated, and foals assumed their own production of antibodies starting at approximately 20 weeks of age. Overall, colts shed higher numbers of strongylid, ascarid, and S. westeri eggs than fillies.
Conclusions
This study demonstrated a lack of seasonality in strongylid egg shedding for the study population, which is in stark contrast to previous studies conducted elsewhere. This strongly suggests that more studies should be done investigating these patterns under different climatic conditions.
Graphical Abstract
... The microscope reading is done at a magnification of 100x (86), up to 400x when there are small sized protozoa (87). This technique has become an alternative to the McMaster method, especially in cases where greater accuracy is needed (60), and has been used successfully in different species including goats and horses (88,89). According to Bortoluzzi et al. (86), who compared the precision of the McMaster technique and the Mini-FLOTAC to quantify Eimeria maxima oocysts, the Mini-FLOTAC is a reliable and precise method of quantification for this species with the detection limit ranging between 100 and 500 oocysts per gram of excreta (OPG ...
The poultry industry is one of the main providers of protein for the world's population, but it faces great challenges including coccidiosis, one of the diseases with the most impact on productive performance. Coccidiosis is caused by protozoan parasites of the genus Eimeria, which are a group of monoxenous obligate intracellular parasites. Seven species of this genus can affect chickens (Gallus gallus), each with different pathogenic characteristics and targeting a specific intestinal location. Eimeria alters the function of the intestinal tract, generating deficiencies in the absorption of nutrients and lowering productive performance, leading to economic losses. The objective of this manuscript is to review basic concepts of coccidiosis, the different Eimeria species that infect chickens, their life cycle, and the most sustainable and holistic methods available to control the disease.
... The diagnostic performance of the Mini-FLOTAC has been assessed and compared with the McMaster technique in several mammalian hostparasite studies indicating that the Mini-FLOTAC showed a higher sensitivity, accuracy, and precision (Godber et al., 2015;Cringoli et al., 2017;de Castro et al., 2017;Noel et al., 2017;Scare et al., 2017;Bosco et al., 2018;Paras et al., 2018;Nápravníková et al., 2019;Amadesi et al., 2020). However, there are only two published studies compared the Mini-FLOTAC with the McMaster technique in avian species, one for detecting Eimeria oocysts (Bortoluzzi et al., 2018) and the other for nematode eggs (Daş et al., 2020). ...
Excreta egg counting techniques are used for indirectly estimating the magnitude of gastrointestinal nematode infection in live animals. The aim of this study was to optimise laboratory and field sampling methods for routine monitoring of nematode infections in chickens by evaluating the sensitivity, accuracy, and precision of the Modified McMaster (MM) and Mini-FLOTAC (MF) methods using laying chicken excreta samples spiked with estimated true numbers of eggs (Experiment 1 = 5-1500 EPG (eggs/g); Experiment 2 = 5-500 EPG) without and with operator effects, respectively or using individual fresh excreta (n = 230) and fresh floor excreta (n = 42) from naturally infected free-range layer farms. The Coefficient of Variation (CV) was assessed within and between operators and the time spent on sample preparation and counting was also evaluated. MF was more sensitive than MM at ≤ 50 EPG level but not above this while MM had a significantly higher egg recovery rate than MF for ≥ 50 EPG levels (MM = 89.7%, MF = 68.2%; P < 0.0001). Operator factors did not have a significant effect (P = 0.358-0.998) on egg counts across methods and EPG levels. The CV between replicates of the MM and MF methods for ≥ 50 EPG was 43.4 and 36.5%, respectively. The inter-observer CV of the MM and MF methods for ≥ 50 EPG levels was 63.8 and 44.3% respectively. When the naturally infected free-range layers which were individual caged for excreta sampling, the proportion of samples positive for MM and MF were 91.7 and 96.5%, respectively (P = 0.023). MM resulted in significantly (P = 0.029) higher excreta egg counts (604) than MF (460) with the difference between methods greatest at higher EPG levels. Fresh floor excreta (pooled or individual) and individual caged chicken excreta did not have significant effect on egg counts (P = 0.274). The total time taken for sample preparation and egg counting was significantly lower using the MM method (4.3-5.7 min) than the MF method (16.9-23.8 min) (P < 0.0001). In conclusion, MM was more accurate than MF, particularly at higher EPG levels, but slightly less precise and sensitive, particularly at low EPG levels, while taking less than 25% of the laboratory time per sample. Our observations indicate that the MM method is more appropriate for rapid diagnosis of chicken nematodes in the field. Pooled fresh floor excreta samples would be sufficient to indicate infection level in free range farms.
... eggs when compared with Mini-FLOTAC ® (Napravnikova et al., 2019). Conversely, Mini-FLOTAC ® was found to be more precise than the McMaster technique for strongyles in seven studies (Britt et al., 2017;Noel et al., 2017;Scare et al., 2017;Bosco et al., 2018;Paras et al., 2018;Went et al., 2018;Napravnikova et al., 2019) whereas one study reported similar precision for both techniques (Silva et al., 2019) (Table 4). Tomczuk et al., 2014;Becker et al., 2016;Bosco et al., 2018) reported lower sensitivity of the McMaster technique, while one study (Cain et al., 2020) reported similar sensitivity levels for ...
Faecal egg counting techniques (FECT) form the cornerstone for the detection of gastrointestinal parasites in equines. For this purpose, several flotation, centrifugation, image- and artificial intelligence-based techniques are used, with varying levels of performance. This review aimed to critically appraise the literature on the assessment and comparison of various coprological techniques and/or modifications of these techniques used for equines and to identify the knowledge gaps and future research directions. We searched three databases for published scientific studies on the assessment and comparison of FECT in equines and included 27 studies in the final synthesis. Overall, the performance parameters of McMaster (81.5%), Mini-FLOTAC® (33.3%) and simple flotation (25.5%) techniques were assessed in most of the studies, with 77.8% of them comparing the performance of at least two or three methods. The detection of strongyle, Parascaris spp. and cestode eggs was assessed for various FECT in 70.4%, 18.5% and 18.5% studies, respectively. A sugar-based flotation solution with a specific gravity of ≥ 1.2 was found to be the optimal flotation solution for parasitic eggs in the majority of FECT. No uniform or standardised protocol was followed for the comparison of various FECT, and the tested sample size (i.e. equine population and faecal samples) also varied substantially across all studies. To the best of our knowledge, this is the first systematic review to evaluate studies on the comparison of FECT in equines and it highlights important knowledge gaps in the evaluation and comparison of such techniques.
... For example, this tool produces less false negative results than other techniques widely employed (e.g., McMaster, Modified-Wisconsin) (Cringoli et al., 2017;Paras et al., 2018). In fact, the Mini-FLOTAC is accurate and easier to perform, without the need of scales and filtering debris; in addition, it can be used for fecal analysis in the laboratory or in the field (Noel et al., 2017;Bosco et al., 2018). Conversely, the McMaster method is used to make simple and quick treatment decisions, but it is not recommended for the use of selective therapy and evaluation of anthelmintic efficacy, with a smaller standard deviation (Castro et al., 2017). ...
The proper diagnosis of gastrointestinal parasites of small ruminants requires the development of multivalent techniques characterized by high sensitivity, specificity, precision, reproducibility, and the ability to quickly detect and monitor infections that pose risks to animal health. The aim of this study was to evaluate the performance of Mini-FLOTAC technique and McMaster egg counting (gold standard) in the detection of gastrointestinal parasites of goats and sheep. A total of 789 fecal samples were analyzed (401 of sheep and 388 of goats). From those, nematode eggs were detected in 80.86% (638/789), being 72.57% (291/401) from sheep and 89.43% (347/388) from goats. The Mini-FLOTAC technique presented a better performance to detect helminth eggs in both goats (88.40%; 343/388) and sheep (71.57%; 287/401) (?2 = 10.358; p < 0.0001). Kappa analysis revealed a weak concordance between techniques for goats (k = 0.342; p < 0.001) and sheep (k = 0.281; p < 0.001). Data herein reported suggests that the Mini-FLOTAC is a technique more sensitive than the McMaster egg counting, therefore its use might be adopted for the diagnosis of gastrointestinal infection in small ruminants.
... and did not receive anthelmintic treatment prior to the study. From three months of age, the foals were examined for ascarid fecal egg counts determined in triplicate with the Mini-FLOTAC method as previously described [41] . Once foals exceeded 100 ascarid eggs per gram (EPG), they were ranked by egg count magnitude and blocked into pairs of two. ...
Ascaris and Parascaris are important parasites in the family Ascarididae, large, ubiquitous intestinal-dwelling nematodes infecting all classes of vertebrates. Parasitic nematode drug resistance in veterinary medicine and drug recalcitrance in human medicine are increasing worldwide, with few if any new therapeutic classes on the horizon. Some of these parasites are zoonotic, e.g., Ascaris is passed from humans to pigs and vice versa. The development of new therapies against this family of parasites would have major implications for both human and livestock health. Here we tested the therapeutic ability of a paraprobiotic or dead probiotic that expresses the Bacillus thuringiensis Cry5B protein with known anthelmintic properties, against zoonotic Ascaris suum and Parascaris spp. This paraprobiotic, known as IBaCC, intoxicated A. suum larvae in vitro and was highly effective in vivo against intestinal A. suum infections in a new mouse model for this parasite. Fermentation was scaled up to 350 l to treat pigs and horses. Single dose Cry5B IBaCC nearly completely cleared A. suum infections in pigs. Furthermore, single dose Cry5B IBaCC drove fecal egg counts in Parascaris-infected foals to zero, showing at least parity with, and potential superiority to, current efficacy of anthelmintics used against this parasite. Cry5B IBaCC therefore represents a new, paraprobiotic One Health approach towards targeting Ascarididae that is safe, effective, massively scalable, stable, and useful in human and veterinary medicine in both the developed and developing regions of the worlds.
... The level of detection sensitivity used to complete the pre-and post-treatment counts were consistent within a FECRT. Homogenization of the sample and sodium nitrate solution, slide preparation, and counting were completed as previously described (Noel et al., 2017). ...
A population of Haemonchus contortus that was highly resistant to benzimidazoles and avermectin/milbemycins with a subpopulation that was resistant to levamisole, was replaced with a susceptible laboratory isolate of H. contortus in a flock of sheep. The anthelmintic susceptibility and population genetics of the newly established population were evaluated for 3.5 years using in vivo, in vitro, and molecular methods. Successful replacement of the resistant population with a susceptible population was confirmed using phenotypic and genotypic measurements; larval development assay indicated full anthelmintic susceptibility; albendazole treatment yielded 98.7% fecal egg count reduction; pyrosequence genotyping of single nucleotide polymorphisms in positions 167 and 200 of the isotype-1 beta tubulin gene were present at 0.0 and 1.7%, respectively; microsatellite genotyping indicated the background haplotype was similar to the susceptible isolate; and haplotypes of the isotype-1 beta tubulin gene were similar to the susceptible isolate. To sustain the susceptibility of the new population, targeted selective treatment was implemented using albendazole. Surprisingly, within 1.5 years post-replacement, the population reverted to a resistant phenotype. Resistance to albendazole, ivermectin, and moxidectin was confirmed via fecal egg count reduction test, larval development assay, and pyrosequencing-based genotyping. Targeted selective treatment was then carried out using levamisole. However, within one year, resistance was detected to levamisole. Population genetics demonstrated a gradual change in the genetic structure of the population until the final population was similar to the initial resistant population. Genetic analyses showed a lack of diversity in the susceptible isolate, suggesting the susceptible isolate had reduced environmental fitness compared to the resistant population, providing a possible explanation for the rapid reversion to resistance. This work demonstrates the power of combining molecular, in vitro, and in vivo assays to study phenotypic and genotypic changes in a field population of nematodes, enabling improved insights into the epidemiology of anthelmintic resistance.
... The diagnostic performance of the Mini-FLOTAC has been assessed and compared with the McMaster technique in several mammalian hostparasite studies indicating that the Mini-FLOTAC showed a higher sensitivity, accuracy, and precision (Godber et al., 2015;Cringoli et al., 2017;de Castro et al., 2017;Noel et al., 2017;Scare et al., 2017;Bosco et al., 2018;Paras et al., 2018;Nápravníková et al., 2019;Amadesi et al., 2020). However, there are only two published studies compared the Mini-FLOTAC with the McMaster technique in avian species, one for detecting Eimeria oocysts (Bortoluzzi et al., 2018) and the other for nematode eggs (Daş et al., 2020). ...
Excreta egg counting techniques can provide valuable information for assessing flock infection levels, selecting nematode resistant chicken breeds and for determining anthelmintic efficacy. Although the Modified McMaster (MDM) method has been used for a long time, it is generally considered to have low sensitivity and precision (Das et al., 2020). The Mini-FLOTAC (MF) is a more recently developed commercial flotation method for excreta which could be a good alternative to replace MDM. The aim of this study was to compare the MF to the traditional MDM for their sensitivity, accuracy and precision using egg spiked chicken excreta samples. Time spent on sample processing and operator factors was also evaluated. The diagnostic performance of the methods was compared using chicken excreta spiked with Ascaridia galli in a 2 x 2 x 3 x 4 factorial experiment testing the effects of excreta egg counting method (MDM with analytical sensitivity of 40 EPG, and MF with analytical sensitivity of 5EPG), person preparing the sample (preparer A and B), excreta egg counts (EPG, eggs/g) level (5, 50, 500 EPG) and person doing the egg counting (1, 2, 3, 4). EPG value was tested for normality and transformed by cube root prior to data analysis to meet the best assumption of analysis of variance. EPG and times were subjected to analysis of variance fitting the four effects tested in the model and interactions up to 3-way using JMP 14. The sensitivity of each technique was calculated as follows: [(total number of observed positive samples (true positive)/the total number observation for each EPG level and method)*100]. Moreover, precision (i.e. how close measurements are to each other) was calculated by subtractions of coefficient variation (CV) from 100 (precision = 100-CV). The overall sensitivity of MF and MDM at detecting positive samples across all EPG levels was 79.2% and 68.3%, respectively. However, MF was significantly (P = 0.0467) more sensitive than MDM at the 50 EPG level. The overall mean egg recovery rates of MF and MDM were 24.6 and 35.9 EPG, respectively (P = 0.08). However, the mean egg count between EPG levels was significantly different (P < 0.0001). Furthermore, the logistic interaction between excreta egg counting methods and EPG level was significantly different (P = 0.0026), whereas the two and three ways logistic interaction between methods, preparers and observers did not have a significant effect on mean egg recovery of spiked eggs (P = 0.42-0.97). The average precision of MDM across all EPG levels was 72.6%, whereas it was 77.7% for MF. There were no significant differences between observers and preparers for mean egg count with respective EPG levels and methods; however, operator factors can generally cause an unexplained source of variation. The total time taken for sample preparation and egg counting (slide reading) was significantly lower with MDM (5 min) than with MF (22 min) (P < 0.0001). In conclusion, MDM was relatively more accurate but less sensitive and precise than MF. Taken as a whole, our observation suggests that the MDM method appears to be more appropriate for rapid diagnosis of chicken nematodes in the field. Our finding is in line with a recent study (Das et al., 2020) who concluded that MDM is faster, relatively more accurate but less precise than Mini-FLOTAC.
... Fecal egg counts were performed on individual fecal sample by Mini-FLOTAC R technique according to Noel et al. (22) and Went et al. (23). Briefly, five weighed grams of feces were placed into a Fill-FLOTAC homogenizer and suspended in 45 mL of the NaCl flotation medium (specific gravity 1.25). ...
The increasing levels of anthelmintic resistance together with the restrictions in the use of drugs in food producing animals have enforced the search for sustainable alternative approaches for parasite control. The current study aimed to investigate the safety and the efficacy of a commercially available phytotherapic formulation against gastrointestinal strongyles in donkeys. Twenty-two Ragusana jennies (2.6 ± 0.5 years old) were assigned to two equal groups. One group was treated with two doses of a phytotherapic supplement Paraxitebio® containing Cardus mariano, Eucalyptus globulus, Gentiana lutea, Urtica urens, and Mallotus philippinensis, 14 days apart (Group A). One group was used as negative control (Group B). Individual fecal samples were collected at the beginning of the study (T−1), and after 7, 14, and 28 days (T7, T14, T28). Blood samples were collected on T−1 and T28 in order to assess changes in donkeys' hematological profile. After the initial rise in EPG values observed on T7, Group A showed a significant EPG decrease with lower eggs per gram (EPG) count compared to Group B on T28 and an overall fecal egg count reduction of 56.9% on the same time-point. Hematological parameters were within the normal physiological ranges for enrolled donkeys. However, significant differences in the values of RBCs, Hb, MCHC, MCV, WBCs, eosinophils, and basophils were recorded between groups after phytotherapic treatments, with Group A showing a general improvement in the hemogram picture. The phytotherapic supplement used in the current study was helpful in controlling intestinal parasites allowing a significant reduction in the fecal egg count 28 days after treatment. Further studies are needed to better explore the specific mode of action of the plant-derived formulation herein tested as well as to encourage their use as tool for the control of equine strongylosis under multimodal integrated approach in dairy donkey farms.
Chicken production has increased over the past decade, resulting in a concomitant rise in the demand for more humane options for poultry products including cage-free, free-range, and organic meat and eggs. These husbandry changes, however, have come hand-in-hand with increased prevalence of Ascaridia galli infection, which can cause clinical disease in chickens as well as the occasional appearance of worms in eggs. Additionally, development of anthelmintic resistance in closely related helminths of turkeys highlights the need for closely monitored anthelmintic treatment programs. Manual faecal egg counts (FECs) can be time-consuming and require specialist training. As such, this study sought to validate an automated FEC system for use in detection and quantification of A. galli eggs in chicken faeces. Automated counts using the Parasight System (PS) were compared to traditional manual McMaster counting for both precision and correlation between methods. Overall, ten repeated counts were performed on twenty individual samples for a total of 200 counts performed for each method. A strong, statistically significant correlation was found between methods (R ² = 0.7879, P < 0.0001), and PS counted more eggs and performed with statistically significant higher precision ( P = 0.0391) than manual McMaster counting. This study suggests that PS is a good alternative method for performing A. galli FECs and provides a new tool for use in helminth treatment and control programs in chicken operations.
The life-cycle of the parasitic forms of Halicephalobus gingivalis is yet to be fully understood. In cases where there is evidence to support the presence of eggs from this parasite or its DNA in the faeces of equines, a thorough investigation of the clinical status and gastro-intestinal tract of the affected animals is warranted, as well as detailed descriptions of the employed coprological technique. Since reports of the identification of H. gingivalis eggs in faeces are sparse, objective measurements and high-quality images must be provided, in order to ensure optimal criteria for classification. Regarding research concerning H. gingivalis, no piece of information should be regarded as superfluous.
The World Association for the Advancement of Veterinary Parasitology recently released new recommendations for the design of fecal egg count (FEC) reduction tests for livestock. These provide suggestions as to the number of animals to be sampled and the minimum number of eggs that must be counted to produce statistically meaningful results.
One of the considerations for study design is the multiplication factor of the FEC method to be used; methods with lower multiplication factors require fewer animals to be sampled because they are presumed to count more eggs per test. However, multiplication factor is not the sole determinant of the number of eggs counted by any given method, since different techniques use very different sample extraction methodologies that could affect the number of eggs detected beyond just the amount of feces examined.
In this light, we compared three commonly used manual FEC methods (mini-FLOTAC, McMaster and Wisconsin) and two automated methods (Imagyst and Parasight All-in-One) with respect to how many equine strongylid and ascarid eggs they counted in the same samples.
McMaster and mini-FLOTAC (multiplication factors of 25x and 5x, respectively) produced the most accurate results of the methods tested but mini-FLOTAC counted approximately 5-times more eggs than McMaster. However, Wisconsin and Parasight (multiplication factor = 1x) counted 3-times more ova than mini-FLOTAC, which was less than the 5-fold difference in their multiplication factors. As a result, these tests perform with multiplication factors more akin to 1.6x relative to mini-FLOTAC. Imagyst, due to its unique sample preparation methodology, does not have a traditional multiplication factor but performed similarly to McMaster with respect to egg recovery.
Cattle are natural hosts of a wide variety of gastrointestinal parasites that affect their health and welfare, causing diarrhea, loss of appetite, mild to severe anemia, as well as low productivity, resulting in great economic losses. The objective of the study was to determine the prevalence of gastrointestinal parasites in cattle of the "Niña Bonita" dairy farm in Santa Clara municipality, Villa Clara province, Cuba. Fecal samples were taken and coprological diagnostic techniques of sedimentation and flotation were applied for the identification of parasites. Two genera of nematodes (Strongyloides and Toxocara) and protozoa of the genus Eimeria were identified. The prevalence of gastrointestinal parasites was high, as was the intensity of parasitic infection, which was dominated by moderate and mild infections. The risk of being severely and moderately infected was higher in Strongyloides parasitized animals. It is concluded that parasitic infections continue to be one of the main causes of disease and loss of productivity in livestock farms, so their control is absolutely necessary, where the knowledge of the prevalence of parasitosis, as well as the identification of these parasites, is vital for decision making and the establishment of much more rational and efficient programs.
Background
There is a lack of consensus on how best to balance our need to minimise the risk of parasite‐associated disease in the individual horse, with the need to limit the use of anthelmintics in the population to preserve their efficacy through delaying further development of resistance.
Objectives
To develop evidence‐based guidelines utilising a modified GRADE framework.
Methods
A panel of veterinary scientists with relevant expertise and experience was convened. Relevant research questions were identified and developed with associated search terms being defined. Evidence in the veterinary literature was evaluated using the GRADE evidence‐to‐decision framework. Literature searches were performed utilising CAB abstracts and PubMed. Where there was insufficient evidence to answer the research question the panel developed practical guidance based on their collective knowledge and experience.
Results
Search results are presented, and recommendation or practical guidance were made in response to 37 clinically relevant questions relating to the use of anthelmintics in horses.
Main limitations
There was insufficient evidence to answer many of the questions with any degree of certainty and practical guidance frequently had to be based upon extrapolation of relevant information and the panel members' collective experience and opinions.
Conclusions
Equine parasite control practices and current recommendations have a weak evidence base. These guidelines highlight changes in equine parasite control that should be considered to reduce the threat of parasite‐associated disease and delay the development of further anthelmintic resistance.
Background
Fasciolosis (Fasciola hepatica) and paramphistomosis (Calicophoron daubneyi) are two important infections of livestock. Calicophoron daubneyi is the predominant Paramphistomidae species in Europe, and its prevalence has increased in the last 10–15 years. In Italy, evidence suggests that the prevalence of F. hepatica in ruminants is low in the southern part, but C. daubneyi has been recently reported at high prevalence in the same area. Given the importance of reliable tools for liver and rumen fluke diagnosis in ruminants, this study evaluated the diagnostic performance of the Mini-FLOTAC (MF), Flukefinder(R) (FF) and sedimentation (SED) techniques to detect and quantify F. hepatica and C. daubneyi eggs using spiked and naturally infected cattle faecal samples.
Methods
Briefly, negative bovine faecal samples were artificially spiked with either F. hepatica or C. daubneyi eggs to achieve different egg count levels: 10, 50 and 100 eggs per gram (EPG) of faeces. Moreover, ten naturally infected cattle farms from southern Italy with either F. hepatica and/or C. daubneyi were selected. For each farm, the samples were analysed individually only with MF technique and as pools using MF, FF and SED techniques. Bayesian latent class analysis (LCA) was used to estimate sensitivity and accuracy of the predicted intensity of infection as well as the infection rate in the naturally infected farms.
Results
The outcome of this study showed that the highest number of eggs (F. hepatica and C. daubneyi) recovered was obtained with MF, followed by FF and SED in spiked infected samples at 50 and 100 EPG, while at lower infection levels of 10 EPG, FF gave the best results. Moreover, the sensitivity for all the techniques included in the study was estimated at > 90% at infection levels > 20 EPG for both F. hepatica and C. daubneyi eggs. However, MF was the most accurate of the three techniques evaluated to estimate fluke infection intensity. Nevertheless, all three techniques can potentially estimate infection rate at farm level accurately.
Conclusions
Optimization and standardization of techniques are needed to improve the FEC of fluke eggs.
Graphical Abstract
Traditional treatment for gastrointestinal helminths in grazing livestock often involves untargeted, metaphylactic blanket treatment of animals with anthelmintics. As a result, resistance to anthelmintic drugs has become a significant issue for farmers and veterinarians worldwide, impacting farm profitability and animal welfare. Faecal egg counts (FECs) are an important diagnostic test to combat further anthelmintic resistance as they enable practitioners to better distinguish between animals that require treatment and those that do not. FECs are labour-intensive, time-consuming and require trained personnel to process the samples and visually identify the parasite eggs. Consequently, the time between sample collection, transport, analysis, results, and treatment can take days. This study aimed to evaluate a rapid, on-site parasite diagnostic system utilising a smartphone app and machine learning in terms of its capability to provide reliable egg counts while decreasing the turnaround time for results associated with outsourcing the analysis. A total of 105 ovine faecal samples were collected. Each sample was homogenised and split equally between two containers. One container per sample was processed using the on-site, app-based system, the second container was sent to an accredited laboratory. Strongyle egg counts were conducted via video footage of samples by the system's machine learning (ML) and a trained technician (MT) and via microscopic examination by an independent laboratory technician (LAB). Results were statistically analysed using a generalised linear model using SAS® (Version 9.4) software. The ratio of means was used to determine non-inferiority of the ML results compared to the LAB results. Both system egg counts (ML and MT) were higher (p < 0.0001) compared to those obtained from the laboratory (LAB). There was no statistically significant difference between the ML and MT counts. The app-based system utilising machine learning has been found to be non-inferior to the accredited laboratory at quantifying Strongyle eggs in ovine faecal samples. With its quick result turnaround, low outlay cost and reusable components, this portable diagnostic system can help veterinarians to increase their testing capacity, perform on-farm testing and deliver faster and more targeted parasite treatment to combat anthelmintic resistance.
The aims of this study were to determine the prevalence of helminths in Thoroughbred horses in Rio de Janeiro; make correlations with risk factors for these infections; and compare the efficiency of three floatation solutions applied in the quantitative Mini-FLOTAC technique. Fecal samples from 520 horses were collected from six training centers between 2019 and 2021. These were subjected to the Mini-FLOTAC technique using three solutions: NaCl (density = 1.200 g/mL), ZnSO4 (1.350 g/mL) and ZnSO4 (1.200 g/mL); and also to qualitative techniques. Information on the horses' sex and age of horses was retrieved from the studbook; data on management from a questionnaire. The overall prevalence of intestinal parasites was 71.9%, with significant differences between training centers (P ≤ .05). On farm C, 87.7% of the samples presented strongylids and 38.7% had Parascaris spp., with the highest egg counts per gram of feces (EPG), of 358.33 and 40.41 respectively. Horses less than 3 years of age were about eight times more likely to be parasitized by strongylids and eleven times more likely to have EPG ≥500. The NaCl solution used in Mini-FLOTAC enabled recovery of the greatest number of samples with high EPG and reached the highest sensitivity values in the diagnosis when compared to the other solutions. Moreover, in the diagnoses, the levels of agreement between the results from the solutions used in Mini-FLOTAC were substantial. However, in estimating the EPG, full agreement between the results from the solutions used in Mini-FLOTAC was not obtained.
For the first time this century, we report tract migration dermatitis provoked by Gasterophilus sp. larvae in horses at a farm in Spain where a selective parasite control programme has been employed for more than a decade. At this equine farm, two horses over 25 years old presented alopecic lesions in the form of streaks in the masseteric and maxillary region of the face. The clinical and histological features of these animals are described, with dermatological examination revealing the presence of nonoperculated eggs of Gasterophilus sp. when the lesions appeared. The morphology of the eggs corresponded to G. inermis and skin biopsy identified an eosinophilic superficial perivascular dermatitis. The horses were treated once with oral ivermectin, achieving complete resolution of the lesions.
Fecal egg counts are essential monitoring tools in veterinary parasite control. In recent years, several groups have developed automated egg counting systems based on image analysis and deep learning algorithms. Work in our laboratory demonstrated that an automated system performed with significantly better precision than traditional egg counting techniques. However, while the counting process is no longer operator dependent, the pre-analytical homogenization steps still are. This study aimed at evaluating the influence of sample homogenization on diagnostic performance on an automated equine strongylid egg counting system. Samples were collected from 12 horses and assigned to three egg count categories (four samples per category): Low (0-500 eggs per gram (EPG)), Moderate (501-1000 EPG), and High (1001-2000 EPG). Within each category, all samples were divided into four portions and each was analyzed with the automated system using the following four homogenizing procedures using a homogenizing device supplied with the system: 1) pressing the plunger five times and pouring directly into the counting chamber, 2) pressing the plunger five times and shaking the bottle prior to pouring, 3) pressing the plunger ten times with direct pouring, and 4) pressing the plunger ten times with shaking the bottle before pouring. There were no differences in precision expressed as coefficient of variation between these four procedures but shaking of the bottle prior to pouring was significantly associated with higher counts (p = 0.0068). These results demonstrate that the homogenization process can affect the diagnostic performance of an automated egg counting system and suggest that more efforts should be invested in standardizing and optimizing homogenization procedures.
The first parasite fecal egg counting techniques were described over 100 years ago, and fecal egg counting remains essential in parasitology research as well as in clinical practice today. Several novel techniques have been introduced and validated in recent years, but this work has also highlighted several current issues in this research field. There is a lack of consensus on which diagnostic parameters to evaluate and how to properly design studies doing so. Furthermore, there is a confusing and sometimes incorrect use of terminology describing performance of fecal egg counting techniques, and it would be helpful to address these. This manuscript reviews qualitative and quantitative diagnostic performance parameters, discusses their relevance for fecal egg counting techniques, and highlights some of the challenges with determining them. Qualitative parameters such as diagnostic sensitivity and specificity may be considered classic diagnostic performance metrics, but they generally only have implications at low egg count levels. The detection limit of a given technique is often referred to as the “analytical sensitivity”, but this is misleading as the detection limit is a theoretically derived number, whereas analytical sensitivity is determined experimentally. Thus, the detection limit is not a diagnostic performance parameter and does not inform on the diagnostic sensitivity of a technique. Quantitative performance parameters such as accuracy and precision are highly relevant for describing the performance of fecal egg counting techniques, and precision is arguably the more important of the two. An absolute determination of accuracy can only be achieved by use of samples spiked with known quantities of parasite ova, but spiking does not necessarily mimic the true distribution of eggs within a sample, and accuracy estimates are difficult to reproduce between laboratories. Instead, analysis of samples from naturally infected animals can be used to achieve a relative ranking of techniques according to egg count magnitude. Precision can be estimated in a number of different approaches, but it is important to ensure a relevant representation of egg count levels in the study sample set, as low egg counts tend to associate with lower precision estimates. Coefficients of variation generally provide meaningful measures of precision that are independent of the multiplication factor of the techniques evaluated. Taken together, there is a need for clear guidelines for studies validating fecal egg counting techniques in veterinary parasitology with emphasis on what should be evaluated, how studies could be designed, and how to appropriately analyze the data. Furthermore, there is a clear need for better consensus regarding use of terminology describing the diagnostic performance of fecal egg count techniques.
The coproovoscopic methods involving count chambers are widely used in the veterinary practice for diagnostics. These methods are important in assessments of the prevalence
rates of nematode infections in pigs and for FECR tests. However, more basic data is needed on the effi ciency of the commercial methods of diagnostics, tested at the diff erent specifi c gravity of the fl otation solutions. In a thorough analysis of publications of Ukrainian scientists, we have found that the data is sparse on the efficiency comparison of the modifi ed McMaster’s and MiniFLOTAC methods. The aim of our study was to compare the effi ciency of the commercial coproovoscopic techniques: the modifi ed
McMaster’s method (with sensitivity of 25 EPG), and MiniFLOTAC combined with Fill-FLOTAC (with sensitivity of 5 EPG) in testing for A. suum infection in piglets. Results of approbation of the mentioned methods are presented for the following saturated solutions: NaCl (SG=1.2), MgCl2 ·6H2O (SG =1.27) and NH4NO3 (SG=1.28). Fecal samples were taken at own private farm, in Mlynok village of Onufriivka district, Kirovohrad region from 20 4 month old pigs with spontaneous A. suum infection. The
laboratory assessments were performed in the Scientific Laboratory of Parasitology and Veterinary and Sanitary Expertise of the Poltava State Agrarian Academy. It is established that at high rates of A. suum infection in young pigs, McMaster’s method with the ammonium nitrate solution is more effi cient compared to the Mini-FLOTAC method. In average, 5331.2 eggs of A. suum were determined per 1 g of feces using the former method, compared to 4567.5 EGP according to the Mini-FLOTAC technique (P < 0.001).
The highest diagnostic efficiency of the modifi end McMasters method and the combination of Mini-FLOTAC and Fill-FLOTAC is seen when ammonium nitrate (NH4NO3)
solution of 1.28 SG is used (P < 0.001). Our results add new data on the effi ciency of the commercial methods of diagnostics with varying specifi c gravity of the flotation solutions, for pigs infected with nematodes.
Key words: EPG, pigs, nematode, ascariasis, diagnostics,
effi ciency.
Soil-transmitted helminths and intestinal protozoa infection are widespread in developing countries, yet an accurate diagnosis is rarely performed. The aim of this study was to evaluate the recently developed mini-FLOTAC method and to compare with currently more widely used techniques for the diagnosis of intestinal parasitic infections in different settings.
The study was carried out in Dharamsala, Himachal Pradesh, India, and in Bukumbi, Tanzania. A total of 180 pupils from two primary schools had their stool analyzed (n = 80 in Dharamsala and n = 100 in Bukumbi) for intestinal parasitic infections with three diagnostic methods: direct fecal smear, formol-ether concentration method (FECM) and mini-FLOTAC. Overall, 72% of the pupils were positive for any intestinal parasitic infection, 24% carried dual infections and 11% three infections or more. The most frequently encountered intestinal parasites were Entamoeba coli, Entamoeba histolytica/dispar, Giardia intestinalis, hookworm, (and Schistosoma mansoni, in Tanzania). Statistically significant differences were found in the detection of parasitic infections among the three methods: mini-FLOTAC was the most sensitive method for helminth infections (90% mini-FLOTAC, 60% FECM, and 30% direct fecal smear), whereas FECM was most sensitive for intestinal protozoa infections (88% FECM, 70% direct fecal smear, and 68% mini-FLOTAC).
We present the first experiences with the mini-FLOTAC for the diagnosis of intestinal helminths and protozoa. Our results suggest that it is a valid, sensitive and potentially low-cost alternative technique that could be used in resource-limited settings - particularly for helminth diagnosis.
Commonly used strategies for parasite control in adult horses are based largely on knowledge and concepts that are more than 40 years old. However, much has changed over this time necessitating a re-examination of recommendations for parasite control. In response to this need, the AAEP has formed a Task Force charged with producing a comprehensive set of recommendations for helping veterinarians develop improved strategies and programs for parasite control in horses of all ages. Guidelines will be specified separately for adult and young horses (less than 3 years).
Anthelmintic resistance (AR) is a serious problem for the control of equine gastrointestinal nematodes, particularly in the cyathostomins. The fecal egg count reduction test (FECRT) is the most common method for diagnosing AR and serves as the practical gold standard. However, accurate quantification of resistance and especially accurate diagnosis of emerging resistance to avermectin/milbemycin (A/M) drugs, is hampered by a lack of accepted standards for study design, data analysis, and data interpretation. In order to develop rational evidence-based standards for diagnosis of resistance, one must first take into account the numerous sources of variability, both biological and technical, that affect the measurement of fecal egg counts (FECs). Though usually ignored, these issues can greatly impact the observed efficacy. Thus, to accurately diagnose resistance on the basis of FECRT data, it is important to reduce levels of variability through improved study design, and then deal with inherent variability that cannot be removed, by performing thorough and proper statistical analysis. In this paper we discuss these issues in detail, and provide an explanation of the statistical models and methods that are most appropriate for analyzing these types of data. We also provide several examples using data from laboratory, field, and simulation experiments illustrating the benefits of these approaches.
Accurate diagnosis of parasitic infections is of pivotal importance for both individual patient management and population-based studies, such as drug efficacy trials and surveillance of parasitic disease control and elimination programs, in both human and veterinary public health. In this study, we present protocols for the FLOTAC basic, dual and double techniques, which are promising new multivalent, sensitive, accurate and precise methods for qualitative and quantitative copromicroscopic analysis. These various methods make use of the FLOTAC apparatus, a cylindrical device with two 5-ml flotation chambers, which allows up to 1 g of stool to be prepared for microscopic analysis. Compared with currently more widely used diagnostic methods for parasite detection in animals (e.g., McMaster and Wisconsin techniques) and humans (e.g., Kato-Katz and ether-based concentration techniques), the FLOTAC techniques show higher sensitivity and accuracy. All FLOTAC techniques can be performed on fresh fecal material as well as preserved stool samples, and require approximately 12-15 min of preparation time before microscopic analysis.
A field study was conducted to validate pooled faecal samples in sheep for the assessment of gastrointestinal (GI) strongyle infection intensity (faecal egg count - FEC) and anthelmintic drug efficacy (FEC reduction - FECR). Ten sheep farms located in the Campania region of southern Italy were selected for the study. In each farm, individual faecal samples from 20 adult sheep (when possible) were collected, before (D0) and after (D14) an anthelmintic treatment with albendazole. For each farm and at each time point (D0 and D14) the faecal samples were examined individually and as pools. Specifically, three different pool sizes (5, 10 and 20 individual sheep samples) and three different analytic sensitivities (namely 10 using Mini-FLOTAC; 15 and 50 using the two variants of McMaster - McM15 and McM50) were compared for FEC and FECR using individual and pooled faecal samples. GI strongyle intensity (eggs per gram of faeces - EPG) of pooled samples correlated positively with mean EPG of individual samples, with very high correlation coefficients (ranging from 0.94 to 0.99) across the 3 different pool sizes and analytic sensitivities. Mini-FLOTAC was more sensitive compared to the two variants of McMaster (McM15 and McM50) for the diagnosis of GI strongyles in sheep (100% vs 88.5% vs 75.9%) and resulted in significant higher FEC compared to both McM15 and McM50, with a mean difference in egg counts of approximately 90 EPG (p<0.001). The drug efficacy results showed that FECR was higher than 98% at most farms independently of the pool size and analytic sensitivity. With the exception of two farms, FECR was 100% when calculated for individual animals and across the different pool size and analytic sensitivities. In conclusion, the present study highlighted that pooling ovine faecal samples is a rapid procedure that holds promise as a valid strategy for assessing GI strongyles FEC and FECR in sheep.
Prevalence of several species of naturally acquired internal parasites are reported from a total of 97 horses (mostly mixed lighthorse type) from a farm in central Kentucky. The horses were born and raised in 2 adjacent fields (No. 4 - n=44 and No. 10 − n=53) over a 19-year-period (1971–1989). They were 100 to 537 days old (av. 281) when examined; an exception was a 819-day-old not calculated in the average age. Some of the horses were not examined for all of the parasites. These horses (never previously treated) were all used in critical or controlled tests for evaluation of antiparasitic activity of drugs. Dams and other horses in the fields rarely were given an antiparasitic compound.
Prevalence and aggregate mean numbers of parasites in infected animals (in parentheses) for the 97 horses are: bots — Gasterophilus intestinalis 2nd instar, 65%(45), 3rd instar, 96%(210), Gasterophilus nasalis 2nd instar, 18%(10), 3rd instar, 63%(10); stomach worms — Habronema muscae, 73%(78), Draschia megastoma, 42%(53); ascarids — Parascaris equorum mature, 75%(45), immature 36%(29), tapeworms — Anoplocephala perfoliata, 33%(7); large strongyles — Strongylus vulgaris, 95%(80) (data on horses ≥180 days old), Strongylus edentatus, 94%(34) (data on horses ≥330 days old); pinworms — Oxyuris equi, 43%(87); eyeworms — Thelazia lacrymalis, 61%(6); S. vulgaris in cranial mesenteric artery, 92%(53); and S. edentatus in ventral abdominal wall, 98% (56). Differentiation was made for the data by season and by age of the horses when they were examined. Information from this research reflects the transmission patterns and prevalence of these parasites under natural conditions.
Most veterinarians continue to recommend anthelmintic treatment programmes for horses that derive from knowledge and concepts more than 40 years old. However, much has changed since these recommendations were first introduced and current approaches routinely fail to provide optimal or even adequate levels of parasite control. There are many reasons for this. Recent studies demonstrate that anthelmintic resistance in equine parasites is highly prevalent and multiple-drug resistance is common in some countries, but few veterinarians take this into account when making treatment decisions or when recommending rotation of anthelmintics. Furthermore, the current approach of treating all horses at frequent intervals was designed specifically to control the highly pathogenic large strongyle, Strongylus vulgaris. But this parasite is now quite uncommon in managed horses in most of the world. Presently, the cyathostomins (small strongyles) are the principal parasitic pathogens of mature horses. The biology and pathogenesis of cyathostomins and S. vulgaris are very different and therefore require an entirely different approach. Furthermore, it is known that parasites are highly over-dispersed in hosts, such that a small percentage of hosts harbour most of the parasites. The common practices of recommending the same treatment programme for all horses despite great differences in parasite burdens, recommending prophylactic treatment of all horses without indication of parasitic disease or knowing what species of parasites are infecting the horses, recommending use of drugs without knowledge of their efficacy and failing to perform diagnostic (faecal egg count) surveillance for estimating parasite burdens and determining treatment efficacy, are all incompatible with current standards of veterinary practice. Consequently, it is necessary that attitudes and approaches to parasite control in horses undergo a complete overhaul. This is best achieved by following an evidence-based approach that takes into account all of these issues and is based on science, not tradition.
The faecal egg count reduction test (FECRT) is the method of choice to monitor anthelmintic efficacy against gastro-intestinal nematodes in livestock. Guidelines on how to conduct a FECRT are made available by the World Association for the Advancement of Veterinary Parasitology (WAAVP). Since the publication of these guidelines in the early 1990s, some limitations have been noted, including (i) the ignorance of host-parasite interactions that depend on animal and parasite species, (ii) their feasibility under field conditions, (iii) appropriateness of study design, and (iv) the high detection limit of the recommended faecal egg count (FEC) method. Therefore, the objective of the present study was to empirically assess the impact of the level of excretion and aggregation of FEC, sample size and detection limit of the FEC method on the sensitivity and specificity of the FECRT to detect reduced efficacy (
The faecal egg count reduction test (FECRT) is the recommended method to monitor anthelmintic drug efficacy in cattle. There is a large variation in faecal egg count (FEC) methods applied to determine FECRT. However, it remains unclear whether FEC methods with an equal analytic sensitivity, but with different methodologies, result in equal FECRT results. We therefore, compared the bias, accuracy and precision of FECRT results for Cornell-Wisconsin (analytic sensitivity = 1 egg per gram faeces (EPG)), FLOTAC (analytic sensitivity = 1 EPG) and McMaster method (analytic sensitivity = 10 EPG) across four levels of egg excretion (1-49 EPG; 50-149 EPG; 150-299 EPG; 300-600 EPG). Finally, we assessed the sensitivity of the FEC methods to detect a truly reduced efficacy. To this end, two different criteria were used to define reduced efficacy based on FECR, including those described in the WAAVP guidelines (FECRT <95% and lower limit of 95%CI <90%) (Coles et al., 1992) and those proposed by El-Abdellati et al. (2010) (upper limit of 95%CI <95%). There was no significant difference in bias and accuracy of FECRT results across the three methods. FLOTAC provided the most precise FECRT results. Cornell-Wisconsin and McMaster gave similar imprecise results. FECRT were significantly underestimated when baseline FEC were low and drugs were more efficacious. For all FEC methods, precision and accuracy of the FECRT improved as egg excretion increased, this effect was greatest for McMaster and least for Cornell-Wisconsin. The sensitivity of the three methods to detect a truly reduced efficacy was high (>90%). Yet, the sensitivity of McMaster and Cornell-Wisconsin may drop when drugs only show sub-optimal efficacy. Overall, the study indicates that the precision of FECRT is affected by the methodology of FEC, and that the level of egg excretion should be considered in the final interpretation of the FECRT. However, more comprehensive studies are required to provide more insights into the complex interplay of factors inherent to study design (sample size and FEC method) and host-parasite interactions (level of egg excretion and aggregation across the host population).
Clinically important equine parasites are ubiquitous in managed horse populations. The traditional approach to parasite control is frequent administration of anthelmintics to all horses on a farm. However, increasing levels of anthelmintic resistance is forcing horse owners and veterinarians to shift this control paradigm. Treatment regimens involving routine deworming of all horses throughout the year are now being replaced by more sustainable approaches, which take in to account the importance of maintaining adequate parasite refugia. The selective therapy principle has been recommended for more than 15 years, but there is limited experience with this approach. The relative magnitude of the faecal egg count for an individual horse is a consistent trait, and this provides a reliable basis for selective therapy. But no studies have evaluated the consequences of selective therapy in the long-term, and such studies are strongly needed to validate this approach. Importantly, it remains unclear how selective therapy may affect the prevalence and intensity of other parasites of significant pathogenic potential (e.g. Strongylus vulgaris), which have become uncommon due to years of intensive chemotherapy. Consequently, a selective approach requires vigilant surveillance of the parasite fauna and intensity. This places a demands for reliable diagnostic tools. Also noteworthy is the fact that the majority of equine nematode parasites are more pathogenic during their larval stages, when they cannot be detected by traditional egg counting techniques. Consequently, parasite-specific diagnostic tools capable of assessing prepatent parasite burdens, and able to differentiate between strongyle species of different pathogenic potentials, would be of great value to the equine clinician. Tools for detecting infections with the tapeworm Anoplocephala perfoliata are laborious, difficult to interpret, and at present there is no established method to evaluate treatment efficacy. Thus, better diagnostic tools are needed for tapeworms as well. Biological control, especially the predacious fungi have demonstrated good potential as an adjunct for strongyle control and such a product could easily have a market in equine establishments. In summary, there is general agreement that the traditional treat-all at frequent interval approach should be abandoned, and that optimal parasite control can be maintained with far fewer anthelmintic treatments. But better diagnostic techniques and more evidence documenting the long-term consequences of selective therapy programs are needed to develop and validate systems for sustainable equine parasite control.
Epidemiology, diagnosis and control of helminth parasites of swine
- A Roepstorff
- P Nansen
Roepstorff A, Nansen P. Epidemiology, diagnosis and control of
helminth parasites of swine. In: FAO Animal Health Manual No. 3.
Rome: Food and Agriculture Organization of the United Nations;
1998.