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Potential impact of Neospora caninun infection on farm productivity of fallow deer ( Dama dama )
Abstract
Most evidence suggesting vertical transmission as the predominant transmission route has been obtained from serological studies. Thus a modified ELISA procedure to detect antibodies in the sera of animals (Dama dama) living in farm conditions in a field station was investigated. Two groups of animals were formed: Group I consisting of 15 hinds naturally infected with Neospora caninum, and Group II consisting of 15 uninfected hinds.
In Group I, eleven offspring were born in 2013, another nine in 2014, and eight in 2015. In Group II, 14 offspring were born in 2013, 13 in 2014 and 13 in 2015. All offspring in Group II were seronegative against N. caninum. Significantly fewer offspring were born from seropositive hinds (p < 0.05). Infected hinds (Group I) gave 21.4%, 30.8% and 38.5% fewer offspring than uninfected hinds (Group II) in the years 2013, 2014 and 2015, respectively. Additionally, not all offspring born in Group I were seropositive. The overall vertical transmission ratio of N. caninum in naturally infected fallow deer achieved 82.1% (63.6% in 2013, 100% in 2014 and 67.8% in 2015).
This is the first study identifying the impact of the parasite on fallow deer productivity according to a significant reduction in birth rate. And also suggest that, naturally N. caninum infected buck does not appear to transmit infection to the hinds by natural fertilization.
... The study on the seroprevalence of T. gondii and N. caninum in fallow deer in European countries are limited (Bartova et al., 2007;Bień et al., 2012;Cabaj et al., 2017). ...
... In our study, anti-Toxoplasma IgG antibodies were detected using indirect ELISA (ID VET, Montpellier, France) validated for many animal species (Špilovská et al., 2009; Čobadiová et al., 2013). Due to our earlier experience (Bień et al., 2012;Cabaj et al., 2017) antibodies to N. ...
Toxoplasma gondii and Neospora caninum are coccidian parasites with a global distribution that cause reproductive failure and production losses in livestock. The seroprevalence of both parasite species in ruminants and Cervidae has been investigated worldwide and found to vary greatly.
Studies carried out on mixed flocks with three ruminant species (sheep, goats and fallow deer) living under the same conditions are excellent models for identifying any differences in the rate of infection with the two parasites between the animal species. Additionally, the species used in the present study differ in their feeding categories: grazers, browsers and intermediate feeders. The aim of the study is to identify any variation in the prevalence of the two parasites in mixed flocks and to identify any possible relationships with food choice.
The seroprevalence against T. gondii and N. caninum in 167 captive fallow deer, 64 sheep and 39 goats were detected using commercially-available enzyme-linked immunosorbent assay (ELISA). The seroprevalence for T. gondii achieved 10% in fallow deer, 21% in goats and 47% in sheep. The seroprevalence for N. caninum achieved 13% in sheep and fallow deer and 21% in goats. Overall, 53% of the sheep, 33% of the goats and 22% of the fallow deer were seropositive for both infections. Coinfection of T. gondii and N. caninum was detected in 6% of sheep, 8% of goats and 2% of fallow deer. Statistical analyses of the seroprevalence levels observed among two parasites for each animal species revealed that only the results obtained for sheep were significant (p < 0.01). Additionally, the differences of the seroprevalence levels for T. gondii between sheep and goats and between sheep and fallow deer were statistically significant (p < 0.01). The results of the N. caninum seroprevalence levels observed among animal species were not significant.
Although the variations in susceptibility to T. gondii and N. caninum infections demonstrated by the examined animals may affect the differences in seropositivity, these appear to be related to the feeding habits of the animal species. Therefore, the risk of infection by agents found close to the ground, such as coccidian oocysts, varies. Sheep as grazers are at a greater risk of infection by T. gondii than goats and fallow deer.
... A fatal case of meningoencephalomyelitis caused by N. caninum was diagnosed in a 3 weeks fallow deer in a zoo in Switzerland (Soldati et al. 2004). A study conducted at a fallow deer farm (Cabaj et al. 2017) revealed that the mean vertical transmission ratio of N. caninum in naturally infected deer seems to be comparable to those observed in cattle and showed a significant reduction in birth rate. Bucks naturally infected by N. caninum cannot transmit the infection to females by natural fertilization. ...
... A fatal case of meningoencephalomyelitis caused by N. caninum was diagnosed in a 3 weeks fallow deer in a zoo in Switzerland (Soldati et al. 2004). A study conducted at a fallow deer farm (Cabaj et al. 2017) revealed that the mean vertical transmission ratio of N. caninum in naturally infected deer seems to be comparable to those observed in cattle and showed a significant reduction in birth rate. Bucks naturally infected by N. caninum cannot transmit the infection to females by natural fertilization. ...
... A fatal case of meningoencephalomyelitis caused by N. caninum was diagnosed in a 3 weeks fallow deer in a zoo in Switzerland (Soldati et al. 2004). A study conducted at a fallow deer farm (Cabaj et al. 2017) revealed that the mean vertical transmission ratio of N. caninum in naturally infected deer seems to be comparable to those observed in cattle and showed a significant reduction in birth rate. Bucks naturally infected by N. caninum cannot transmit the infection to females by natural fertilization. ...
This comprehensive species-specific chapter covers all aspects of the mammalian biology, including paleontology, physiology, genetics, reproduction and development, ecology, habitat, diet, mortality, and behavior. The economic significance and management of mammals and future challenges for research and conservation are addressed as well. The chapter includes a distribution map, a photograph of the animal, and a list of key literature.
Neosporosis, a parasitic infection caused by Neospora caninum, is one of the main contagious factors that cause reproductive disturbances in ruminants and neuromuscular complaints in dogs. Deer recognize as the important intermediate host of the N. caninum and plays a critical role in the reserve and dynamics of this parasite. Therefore, this review was performed to determine the global pooled seroprevalence of neosporosis in deer and related factors, including geographic area, climate, serological detection method, deer source and species. Data were systematically gathered without time limitation until 1 March 2021 from the following electronic databases: Pub Med, Springer, Google Scholar, Science Direct, Scopus, Embase, ProQuest, and Web of Science. According to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) and inclusion criteria, 43 eligible studies were obtained from various countries. The funnel plot and Egger’s test showed significant publication bias, and the Trim-and-fill method was used to correct the final meta-analysis. After correction, the overall seroprevalence of neosporosis in deer was 20.9% (95% CI 15–26.8), estimated by the random effect model. The N. caninum infection seroprevalence in deer was the highest in South America (29.8%, 95% CI 20.2–36.1), and the lowest in Europe (5.9%, 95% CI 4.1–7.7). The highest pooled seroprevalence estimation of neosporosis in deer based on diagnostic method subgroup was using NAT (29.8%, 95% CI 13.1–46.4). The pooled seroprevalence of neosporosis in Père David’s deer (42.3%, 95% CI 17.8–66.8) was higher than other deer species. The heterogeneity sources may be deer species and geographic regions based on meta-regression analysis. Understanding the epidemiology of N. caninum infection in deer as reservoir species is required. Furthermore, these results are suitable for managing and controlling this infection in deer.
Neospora caninum was isolated from the brain of an apparently healthy calf born to a seropositive cow. The calf was killed 12 hrs after birth
and homogenate of its brain was inoculated into Vero cells. Neospora-like tachyzoites were detected 66 days later. The identity of the parasite was confirmed by polymerase chain reaction amplification
of N. canium-specific fragments using Np21 and Np6 primers. This first Polish isolate of N. caninum was designated NC-PolB1.
Serum samples from 47 free living and 106 farmed red deer (Cervus elaphus) from the Mazurian Lake District in north-east Poland were investigated for the presence of antibodies to Neospora caninum. A modified Neospora iscom-ELISA was used for initial screening. All sera with optical density (OD) values exceeding 0.400 absorbance units were further investigated by Western blot analysis. Eighteen sera were positive in both tests. Six of these were from free living and 12 from farmed animals giving prevalence of 13 and 11%, respectively. This is the first report of N. caninum infection in farmed and free-living red deer living in the same region where neosporosis was confirmed in cattle and the first evidence of exposure to the parasite in red deer in Poland.
From 2003 through 2007, serum samples from 5594 dairy and beef heifers and cows in Argentina were assessed to quantify the association between presence of Neospora caninum antibodies and history of abortion, type of exploitation, and age category of animals. Animals with a history of abortion were 85% more likely (P<0.01) to be positive to N. caninum than animals without a record of abortion. For a given category (age) of animals, being in a dairy operation increased the odds of being N. caninum-positive. Replacement dairy heifers were 76% more likely (P<0.01) to be N. caninum-positive than beef cows. These results suggest that postnatal exposure may be more frequent in dairy operations than in beef herds and provide insight into the epidemiology of the disease in one of the most important livestock production regions of the world.
Neospora caninum infection was diagnosed in 5 young dogs from 2 litters with a common parentage. The pups were born healthy, but developed hind limb paresis 5 to 8 weeks after birth. The predominant lesions were polyradiculoneuritis and granulomatous polymyositis. Neospora caninum was seen microscopically in sections of naturally infected pups, and was isolated in cell cultures, mice, and dogs inoculated with infected canine tissues. Antibodies to N caninum were detected in sera of infected dogs by indirect fluorescent antibody test.
Parasite-specific antibody responses were detected using an indirect fluorescent antibody (IFA) test in cattle that were naturally or experimentally infected with Neospora parasites. The test was developed using Neospora tachyzoites isolated from an aborted bovine fetus and grown in bovine cell cultures (isolate BPA1). In all cases, infections were confirmed by the identification of Neospora tachyzoites and/or bradyzoite cysts in fetal or calf tissues using an immunoperoxidase test procedure. Fifty-five naturally infected cows that aborted Neospora-infected fetuses had titers of 320-5,120 at the time of abortion. The titer of 6 cows that were serologically monitored over a prolonged period decreased to 160-640 within 150 days after they aborted infected fetuses. Two of the cows showed an increase in their Neospora titers during their subsequent pregnancy, and they gave birth to congenitally infected calves that had precolostral titers of 10,240-20,480. Postcolostral titers of these calves and of 4 other calves with congenital Neospora infections were all > or = 5,120, whereas calves with no detectable parasites had titers < or = 160. Two pregnant heifers that were experimentally infected with the BPA1 isolate at approximately 120 days gestation seroconverted to Neospora antigens within 9 days and developed peak titers of 5,120 and 20,480 within 32 days of infection. The fetus taken by caesarean section 32 days postinfection from 1 heifer and the full-term calf born to the other had Neospora titers of 640 and 10,240, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
A prospective cohort study was undertaken on two central California dairies, A and B, to estimate prevalence of congenital infection with Neospora caninum, to characterize temporal variation in prevalence, to determine if occurrence of congenital infection was associated with specific dam and calf attributes, and to estimate the effect of congenital infection on calfhood mortality. Of the 405 calves enrolled over a period of 2 1/2 y on dairy A and dairy B, 30.6% (85/278) and 53.5% (68/127), respectively, were seropositive precolostrally to N. caninum, as determined by an ELISA test. Adult cow seroprevalence at calving was 36.0% (82/228) for dairy A, and 57.9% (33/57) for dairy B. No evidence was found for a significant increasing or decreasing trend in adult and precolostral seroprevalence through the study period (P > or = 0.26). For both herds combined, 81% of seropositive cows (93/115) and 5% of seronegative cows (8/170) had congenitally infected calves. Seroprevalence did not increase with cow age on either dairy (P > or = 0.47). The probability of a calf being congenitally infected was not associated with dam age, dam lactation number, dam history of abortion, calf gender, or length of gestation (P > or = 0.11). High dam ELISA values at calving were significantly associated (P < or = 0.001) with an increased probability of congenital infection in her calf. Results of survival analyses of female calves available for follow-up indicated a consistently greater survivorship to 90 d in congenitally infected calves than in noninfected calves on both dairies, which was significant for dairy A (P = 0.07, n = 186) but not for dairy B (P = 0.69, n = 72), thus indicating that congenital infection does not necessarily have a detrimental effect on calf health. The findings of a similar magnitude in congenital infection rate and adult cow prevalence, the lack of increasing seroprevalence with cow age, the lack of an effect of dam age on precolostral seropositivity, and the constant seroprevalences during the study period, suggest that, in the two dairies studied, congenital transmission constituted a substantial amount of infection and was likely the major mode of transmission of N. caninum.
Point-source infections are most likely the cause for Neospora caninum-induced abortion outbreaks in cattle, whereas an increased annual abortion rate may be a consequence of vertical transmission. The aims of the present study were to examine the reproductive effects of neosporosis in a beef herd for 3 years, after a point-source outbreak and to use IgG avidity serology to examine the chronicity of infections and patterns of transmission. During the study, 76-78% of animals were seropositive for N. caninum. The pregnancy rate varied from 88% to 94%, without any reduction in the pregnancy rate of seropositive cows compared with seronegative cows. The annual abortion rate was 2.5-5.5%, and all but 1 abortion occurred in seropositive dams. The efficiency of vertical transmission was estimated to be 85%. Several calves, born to seronegative dams, were seropositive at 6-13 months of age, indicating a 22% mean annual rate of horizontal transmission. The mean avidity in seropositive cows increased from 30 during the initial outbreak to 74 after 3 years. The mode of IgG avidity was 21-40 during the initial abortion outbreak, 41-60 after 1 year, and 61-80 after 2 and 3 years. The results reveal high annual rates of both vertical and horizontal transmission of N. caninum in a herd of beef cows and provide further validation on the ability of the N. caninum IgG avidity ELISA to accurately assess the chronicity of infection.
Neospora caninum is a protozoan parasite of animals. Until 1988, it was misidentified as Toxoplasma gondii. Since its first recognition in dogs in 1984 and the description of the new genus and species Neospora caninum in 1988, neosporosis has emerged as a serious disease of cattle and dogs worldwide. Abortions and neonatal mortality are a major problem in livestock operations, and neosporosis is a major cause of abortion in cattle. Although antibodies to N. caninum have been reported, the parasite has not been detected in human tissues. Thus, the zoonotic potential is uncertain. This review is focused mainly on the epidemiology and control of neosporosis in cattle, but worldwide seroprevalences of N. caninum in animals and humans are tabulated. The role of wildlife in the life cycle of N. caninum and strategies for the control of neosporosis in cattle are discussed.
Transmission parameters of Neospora caninum infections in dairy cattle were determined in six herds with a history of Neospora-associated abortions, using an antibody-detection ELISA to detect evidence of infection. A total of 124 seropositive dams and their calves were tested at calving to estimate vertical transmission, and 154 seronegative heifers were monitored prospectively from birth for evidence of post-natal infection. The probability of vertical transmission was very high; 95.2% (95% confidence interval: 89.8%, 98.2%) of the seropositive dams produced calves that were seropositive prior to consumption of colostrum. In the prospective study, three heifers seroconverted, by 1, 8 and 16 months of age, and the overall incidence rate of seroconversion was 1.9 per 100 heifer-years at risk, ranging from 0 to 4.1 per 100 heifer-years at risk within herds. If heifers with inconclusive ELISA results were included in the analysis, the incidence rate of seroconversion was 3.8 per 100 heifer-years at risk, ranging from 0 to 8.3 per 100 heifer-years at risk within herds. This study showed that vertical transmission was the major route involved in the spread of N. caninum in these herds, and that there was only a low detectable level of horizontal transmission. However, further studies are needed to provide parasitological evidence of infection in those heifers that seroconverted.
Sera from 335 farmed fallow deer (Dama dama) at the breeding station in Kosewo Górne in the Mazurian Lake District, North-East Poland, were investigated for the presence of antibodies against Neospora caninum. The distribution of age groups was as follow: >4 years - 154 animals; 2 years - 76 animals; 1 year - 105 animals. Ten sera with the optical density exceeding 0.159 absorbance units (i.e., cut-off value) in ELISA test were also analyzed by Western blot. Western blot analysis revealed seroreactivity against immunodominant N. caninum antigens of 37, 25, and 16kDa; however, in some sera additional bands were also visible. This is the first screening studies for antibodies against N. caninum in farmed fallow deer in Poland, in the region where neosporosis was confirmed in cattle and in farmed and free-ranging European red deer (Cervus elaphus).
Vertical transmission of the protozoan parasite, Neospora caninum is highly efficient and can take two forms - endogenous transplacental transmission resulting from activation of the quiescent bradyzoite stage during pregnancy or exogenous transplacental transmission resulting from ingestion of oocysts during pregnancy. Calves born carrying infection derived from either endogenous or exogenous transplacental transmission are capable of infecting their offspring when they start to breed. This review considers firstly the frequency with which exogenous and endogenous transmission occur, secondly the role of the immune response in controlling N. caninum infection and thirdly how the parasite persists in an immune-competent host and is re-activated during pregnancy.
Four bulls and 56 heifers seronegative to Neospora caninum were used to determine the feasibility of venereal transmission in bovine neosporosis under natural conditions. Bulls were experimentally infected with 10(8) live N. caninum tachyzoites. Two of them with the Nc-1 isolate and the other two with the Nc-Spain-7 isolate. After 13 months of initial infection, each bull was re-infected with the same isolate and dose. The experiments were carried out from March to September during 2006 and 2007 where groups of cyclic heifers were naturally mated by the experimentally infected bulls. In year 2006, two bulls infected with different N. caninum isolate serviced 12 heifers each. In year 2007, the same bulls serviced the same heifers a second time (now primiparous) and six new heifers were also added to each group. In addition, the other two bulls serviced 10 additional heifers each. Experimental animals were monitored for 30 weeks and serum samples were collected weekly and fortnightly in years 2006 and 2007, respectively to evaluate the presence of specific antibodies to N. caninum. Experimentally infected bulls showed a significant increase of specific IgG antibodies from 13 (Nc-SP-7) and 21 (Nc-1) days post-infection. Serum IgG antibody responses of individual animals were similar in kinetics but slightly different in magnitude. Serum samples from heifers were all negative. Pregnant rates were 100% in heifers and 91% in primiparous animals. Calves did not show precolostral specific antibodies to N. caninum. Venereal transmission of bovine neosporosis under natural grazing conditions is unlikely to occur.
Using an improved method of gel electrophoresis, many hitherto unknown
proteins have been found in bacteriophage T4 and some of these have been
identified with specific gene products. Four major components of the
head are cleaved during the process of assembly, apparently after the
precursor proteins have assembled into some large intermediate
structure.
To determine whether heifers with naturally acquired congenital exposure to Neospora sp would transmit the infection to their offspring during gestation.
Prospective cohort study.
Neonatal heifers on a dairy with a history of Neospora sp infections were selected for the study on the basis of their serum titers to Neospora sp, as determined by the use of indirect fluorescent antibody testing. Seropositive heifers (n = 25) had titers > or = 1:5,120 and seronegative heifers (25) had titers < or = 1:80. All heifers were raised and bred on the dairy, and samples were obtained from heifers and their calves at the time of calving.
Blood samples were tested for Neospora sp antibodies. Histologic evaluations, Neospora sp immunohistochemical examinations, and protozoal culturing were performed on samples obtained from selected offspring (second-generation calves).
Seropositive heifers gave birth to calves with titers > or = 1:1,280 to Neospora sp. All offspring from seropositive heifers that were necropsied had evidence of Neospora sp infection. All seronegative heifers and their offspring had titers < 1:80 to Neospora sp.
Congenitally acquired Neospora sp infection can persist in clinically normal heifers and be transmitted transplacentally to their offspring. Vertical transmission can be a way by which neosporosis is maintained in herds.
In spite of the global importance of neosporosis as a cause of bovine abortion, there is very little information about its economic consequences. The economic costs are a product of estimations of the quantity of the effects attributable to Neospora infection, and the particular unit costs of those effects. In this brief review, which arose from a workshop on the economics of coccidiosis held at the COST 820 meeting, Toledo 1998, we discuss the possible effects of neosporosis which are of economic significance and summarise the available estimates of their magnitude to provide a basis for further economic analysis. Neospora infection has been associated with abortion, increased culling and reduced milk yield. In addition, it has been diagnosed in cases of stillbirth and neonatal mortality, it is likely to contribute to early foetal death and resorption and it is responsible for a reduction in the value of female breeding cattle. In quantifying the role of Neospora, it is important that epidemiologically based, case-controlled studies are conducted because, given the extreme efficiency with which bovine Neospora infection is vertically transmitted, demonstration of prevalence of infection in affected animals (including foetuses) is not a true indicator of the significance of this disease. Relatively few epidemiological studies have been conducted, but in investigations in the USA, Holland and Britain, infected cows have been shown to be about three times more likely to abort than non-infected cattle. In the UK this approach has been used to estimate the proportion of abortions in the national dairy population which may be attributable to Neospora caninum.
We assessed a serological method for detecting Trichinella infection in horses, specifically, an ELISA using three antigens to detect anti-Trichinella IgG (i.e. a synthetic tyvelose glycan-BSA (stg-BSA) antigen, an excretory/secretory (ES) antigen, and a crude worm extract (CWE) antigen). Serum samples were collected from 2502 horses (433 live horses from Romania and 2069 horses slaughtered in Italy and originating from Italy, Poland, Romania, and Serbia). Serum samples were also taken from horses experimentally infected with different doses of T. spiralis and T. murrelli larvae, as controls. The cut-off value of ELISA was determined on serum samples from 330 horses from Trichinella-free regions of Italy, which were also examined by artificial digestion of preferential-muscle samples. In the experimentally infected horses, the stg-BSA and ES antigens were less sensitive than the CWE antigen. Trichinella spiralis showed a higher immunogenicity than T. murrelli, and the IgG immunoresponse was dose-dependent. The kinetics of anti-Trichinella IgG were similar among all experimentally infected horses. No circulating antibodies were detected 4-5 months after experimental infection, although these horses still harbored infective larvae. Depending on the antigen used, for 4-7 of the 330 horses from Trichinella-free areas, the optical density (OD) of the serum sample was higher than the cut-off value, yet these samples were negative when subjected to Western Blot. Similar results were obtained for the 1739 horses slaughtered in Italy (originating from Italy, Poland, Romania, and Serbia) and the 433 live Romanian horses. Of the 4 horses with muscle larvae, only one was positive by ELISA and Western Blot. Because the anti-Trichinella IgG remain circulating for only a short period of time, whereas the larvae remain infective for longer periods, serology cannot be used for either diagnosing Trichinella infection in horses or estimating the prevalence of infection. Artificial digestion of at least 5 g of preferential-muscle tissue continues to be the method of choice at the slaughterhouse for preventing equine-borne trichinellosis in humans.
This study describes qualitative and quantitative antibody response in cows naturally infected with Neospora caninum. The study was carried out with 269 serum samples obtained from 24 cows over a period of 15 weeks. Prior to sample collection, the cows were tested with ELISA. The 269 samples were screened with IFAT and categorized into seven IFAT titre groups (< 1 : 80, 1 : 80, 1 : 200, 1 : 600, 1 : 1000, 1 : 2000, > 1 : 2000). The samples were finally analysed by Western blotting. Seven immunodominant antigens (approximately 18-, approximately 25-, approximately 33-, approximately 35-36-, approximately 45-46-, approximately 47-, approximately 60-62 kDa) and five minor antigens (approximately 25, approximately 51, approximately 64, approximately 77, approximately 116 kDa) were recognized by cow sera. The recognition of approximately 46 kDa antigen by cow sera was common to samples with IFAT titre 1 : 80 and above. Another common antigen was the approximately 18 kDa antigen, which was recognized by samples with IFAT titre 1 : 200 and above. The most remarkable observation was the presence of the 45-46 kDa, the 77 kDa, and absence of the 18 kDa antigenic bands in samples with IFAT titre 1 : 80. This observation was consistent even in the face of fluctuating antibody titre where serum antibody titres from an animal exceeded then failed to reach 1 : 80. Antibody fluctuation was observed across all cows (pregnant and aborted) with no discernible fluctuation pattern. However, the fluctuation in antibody titre observed appeared to be most remarkable in initially ELISA-negative pregnant cows, and to a lesser extent in ELISA-positive pregnant cows, and ELISA-positive aborted cows. Although there was fluctuation in antibody titre, the banding patterns of N. caninum tachyzoite antigens by cows within the same IFAT titre group remained similar.
To determine the contribution of Neospora caninum to abortions on a dairy farm in NSW (Australia), determine the mode of transmission and develop and trial a control option for infection.
Two whole herd bleeds were conducted 12 months apart and the association between serological status and abortion events were calculated for a number of bovine abortifacients. Family trees were constructed for N. caninum seropositive cattle in the herd. Some N. caninum seropositive cows were culled from the herd and no female offspring was retained from seropositive cows.
At the first whole-herd bleed in December 2002 a seroprevalence of 10.2% for N. caninum infection was detected. Cows with N. caninum infection were 13 times more likely to abort than uninfected ones. Seventy-five percent of seropositive animals in the herd were related, suggesting a high degree of congenital infection/transmission. Only 15% of infections were likely to be postnatally acquired. Selective culling of seropositive cows and not breeding from them reduced the number of seropositive animals. Only one newly sero-converted cow was detected at the second whole-herd bleed 12 months later.
Seroepidemiological approaches were able to establish a high degree of association between N. caninum infection and low-level abortion in the dairy herd. Vertical transmission of infection was the predominant mode of infection and hence control efforts aimed at selectively culling seropositive animals from the herd were highly successful in reducing the level of infection.
It is clear from researching the vertical transmission of Neospora caninum in cattle that the terms 'vertical', 'congenital' and, indeed, 'transplacental' are inadequate for describing two extremely different situations that have fundamentally different immunological, epidemiological and control implications. A similar situation pertains to Toxoplasma gondii in different hosts. We advocate the use of the terms 'endogenous transplacental infection (TPI)' to define foetal infection from a recrudescent maternal infection acquired before pregnancy (and probably prenatally) and 'exogenous TPI' to define foetal infection that occurs as a result of an infection of the dam during pregnancy.
Herd, within-herd and animal prevalences for Neospora caninum in beef and dairy cattle were compared between four countries. In randomly selected herds from regions of Germany, The Netherlands, Spain and Sweden that were representative for the cattle production of these countries, all animals ≥2 years were examined serologically by enzyme-linked immunosorbent assays (ELISAs) with high test specificity (>98.0%). In a previous study, the ELISAs had been validated against each other. Single reacting animals within a herd were confirmed by immunobloting. At the time of sampling, animal (age, breed, herdtype, sex, lactation stage) and herd data (region) were collected.
The protozoan parasite Neospora caninum is a major cause of abortion in cattle. The diagnosis of neosporosis-associated mortality and abortion in cattle is difficult. In the present paper we review histologic, serologic, immunohistochemical, and molecular methods for dignosis of bovine neosporosis. Although not a routine method of diagnosis, methods to isolate viable N. caninum from bovine tissues are also reviewed.
White-tailed deer (Odocoileus virginianus) serve to maintain the Neospora caninum life cycle in the wild. Sera from white-tailed deer from south central Wisconsin and southeastern Missouri, USA were tested for antibodies to N. caninum by Western blot analyses and two indirect ELISAs. Seroreactivity against N. caninum surface antigens was observed in 30 of 147 (20%) of WI deer and 11 of 23 (48%) of MO deer using Western blot analysis. Compared to Western blot, the two indirect ELISAs were found to be uninformative due to degradation of the field-collected samples. The results indicate the existence of N. caninum antibodies in MO and WI deer, and that Western blot is superior to ELISA for serologic testing when using degraded blood samples collected from deer carcasses.
Dynamic increase in fallow deer and red deer farming in Poland (in Polish)
- B Borys
- Z Bogdaszewska
- M Bogdaszewski
Borys, B., Bogdaszewska, Z., Bogdaszewski, M., 2012. Dynamic increase in fallow deer
and red deer farming in Poland (in Polish). Wiad. Zootechniczne 1, 33-44.