Evaluation of Toxoplasma gondii and Neospora caninum infections in sheep from Uberlandia, Minas Gerais State, Brazil, by different serological methods

Laboratório de Imunoparasitologia, Instituto de Ciências Biomédicas, Universidade Federal de Uberlândia, Av. Pará 1720, 38400-902 Uberlândia, MG, Brazil.
Veterinary Parasitology (Impact Factor: 2.55). 10/2010; 175(3-4):252-9. DOI: 10.1016/j.vetpar.2010.10.017
Source: PubMed

ABSTRACT Toxoplasmosis and neosporosis have been recognized as economically important diseases with considerable impact on the livestock industry. Considering the scarce information on the occurrence of Toxoplasma gondii and Neospora caninum infections in sheep from Uberlândia, Minas Gerais State, Brazil, this study aimed to investigate the frequency of antibodies against these parasites in sheep sera from this region by using different serological methods. A total of 155 sheep serum samples were analyzed by the indirect fluorescence antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA) for the detection of IgG against T. gondii and N. caninum. Seroreactivity by IFAT showed 80% of samples with titers between 512 and 2048 for T. gondii (cutoff ≥ 64) and 78% presenting titers between 50 and 200 for N. caninum (cutoff ≥ 50). Seroreactivity by ELISA showed 75% of samples with ELISA index (EI) between 2.0 and 3.0 for T. gondii (cutoff ≥ 1.3) and 54% presenting EI between 1.3 and 2.0 for N. caninum (cut off ≥ 1.3). Discordant results by both tests were analyzed by immunoblot, resulting in a total seropositivity of 61% for T. gondii and 23% for N. caninum, with 41% to T. gondii only, 3% to N. caninum only, and 20% to both parasites. There was a significant positive association between seropositivity to T. gondii and age over one year (P<0.001), but such association was not found for N. caninum infection. In conclusion, as T. gondii and N. caninum infections are simultaneously present in sheep flocks of this region, it should be emphasized the importance to carry out a regular monitoring of Toxoplasma infection due to its high prevalence, its zoonotic potential and induction of reproductive disorders leading to economic losses. For neosporosis, sheep farmers should be instructed about the presence of the parasite in the flock, its risk factors and potential abortifacient role in sheep. Differential flock management could be valuable tool to establish the association of serological positivity and reproductive disease induced by N. caninum in sheep.

1 Follower
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Eighteen mature ewes of the Mytilene breed and 18 mature Local- Damascus crossbred goats, seronegative for Toxoplasma gondii (T. gondii) by ELISA were used. All animals were mated after synchronization of estrus. On day 90 of pregnancy, animals were randomly assigned to 3 experimental groups; 6 ewes (S1) and 6 goats (G1) were orally inoculated by stomach tube with 1000 oocysts; 6 ewes (S2) and 6 goats (G2) were orally inoculated with a non-infected control inoculum. On day 140+2 of pregnancy, the remaining 6 ewes (S3) and 6 goats (G3) were inoculated by stomach tube with 3000 oocysts. Positive T. godii DNA was detected in 94% of fetal and maternal blood, 95% fetal tissue, 89% pre-colostral udder secretions and 12.5% milk samples using Polymerase Chain Reaction (PCR). Infected animals and their live newborns was seropositive (ELISA) until the end of the study. PCR was able to detect T. gondii DNA in maternal blood of infected animals 3-5 days before abortion occurred. This time period may be used to implement preventive and therapeutic measure to reduce abortion rate and associated economic losses. Since milk and milk products are important food sources in rural areas and in many cases it is used unpasteurized before consumption. The T. gondii DNA, detected by PCR in milk samples of infected animals, increases the possibility that the parasite is transmitted through consumption of unpasteurized milk which is a highly relevant result for public health considerations and providing valuable information for future research.
    Pakistan Veterinary Journal 07/2013; · 1.39 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to describe the occurrence of antibodies to Toxoplasma gondii and Neospora caninum in dairy sheep from the Humid Pampa region, Argentina. Blood samples from 704 dairy sheep belonging to six flocks were collected. Using a cut off titer of 1:50, an indirect fluorescence antibody test was used. Antibodies to T. gondii or N. caninum were detected in 17.3 % (n = 122) and 3 % (n = 21), respectively. All the flocks had at least one seropositive animal to T. gondii but two of them had no seropositive sheep to N. caninum. Fifty-two of 122 (42.6 %) positive samples to T. gondii had antibody titers higher than 1:400. There was a significantly higher proportion of T. gondii seropositive animals in females and older sheep (p < 0.05). Ten of 21 (52.3 %) positive samples to N. caninum had antibody titers higher than 1:400. This is the first report of seroprevalence of T. gondii and N. caninum in dairy sheep from Humid Pampa, Argentina. Further research is required for a better understanding of the role of toxoplasmosis and neosporosis in dairy sheep in Argentina.
    Tropical Animal Health and Production 03/2013; 45(7). DOI:10.1007/s11250-013-0396-1 · 0.97 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to determine the prevalence and risk factors associated with infection due to Neospora caninum in serum samples from 488 sheep originating from 63 farms in 63 municipalities distributed across eight of the twelve mesoregions of the state Minas Gerais, southeastern Brazil. For detection of N. caninum the sheep serum samples were subjected to the indirect fluorescence antibody test (IFAT ≥ 50). To identify the risk factors associated with infection due to N. caninum a questionnaire was filled out for each herd by interviewing, the individual responsible for the herd, demanding information on the general characteristics of the property. Sixty-four sheep sera (13.1%; 95% CI=10.3-16.4) presented IgG-specific anti-N. caninum antibodies with the following titers: 50 (49; 76.6%), 100 (7; 10.9%), 200 (4; 6.2%), 400 (3; 4.7%) and 800 (1; 1.6%). The prevalence of infected sheep per mesoregion ranged from 0 to 28.1%. Out of the 63 farms sampled, 31 (49.2%; 95% CI=36.4-62.1) presented at least one seropositive sheep. No significant association was found between the presence of anti-N. caninum antibodies and the risk factors evaluated on the farms, except for the mesoregion variable (p=0.004; OR=0.429; CI95%=0.182-1.008). These results indicate that there is a need for additional research to define the epidemiological importance of this parasite as a cause of reproductive problems in sheep herds in Minas Gerais.
    Veterinary Parasitology 03/2012; 188(1-2):168-71. DOI:10.1016/j.vetpar.2012.03.006 · 2.55 Impact Factor