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: 2.46). 10/2010; 175(3-4):252-9. DOI: 10.1016/j.vetpar.2010.10.017
Source: PubMed


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.

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Available from: José Roberto Mineo, Oct 04, 2015
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    • "These results may be ascribed to the different farming systems adopted in different states and municipalities, as well as the presence of domestic and wild canids and other risk factors to N. caninum infections. The occurrence of infections by N. caninum is not influenced by breed, age or the number of animals in the herd (BARBER, 1998; BECK et al., 2010) and no evidence of any association was observed between these variables and the seropositivity in the studies conducted by Figliuolo et al. (2004), Romanelli et al. (2007), Soares et al. (2009), Ueno et al. (2009), Salaberry et al. (2010) and Rossi et al. (2011). However, in this study, a statistically significant difference was found between the serological results and breed, but not age. "
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    ABSTRACT: Neosporosis is an emergent disease responsible for considerable economic impact due to reproductive losses. Its zoonotic potential remains unknown. This study involved a survey of antibodies to Neospora caninum in slaughtered sheep and their association with epidemiological variables. Serum samples from 596 sheep from the states of São Paulo and Rio Grande do Sul, Brazil, were collected in two slaughterhouses located in São Paulo and evaluated by indirect fluorescence antibody test (IFAT), using cut-off titers of 25. Among these samples, 353/596 (59.23%; 95%CI 55.23-63.10) were positive and 263/353 (74.50%; 95%CI 69.71-78.77%) were from Rio Grande do Sul. Statistical associations were determined in the univariate analysis between the serological results and sex, breed and municipality of origin. Sheep that came from extensive breeding system showed higher chance (OR=2.09) of presenting antibodies to N. caninum in relation to those from semi-intensive system. Higher chance was also observed for the different studied breeds, except Bergamácia, in relation to Hampshire Down. The results revealed the presence of infection by N. caninum in sheep from slaughterhouses.
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    • "South Africa, Samra et al., 2007; 19.88% Southern Pakistan, Mushtaq et al., 2010; 54% Southern Europe, Petersen, 2007 and 80% Brazil, Rossi et al., 2011). Toxoplasmosis causes abortions, reproductive problems and economic losses to sheep and goats industry all over the world (Buxton et al., 2007). "
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    • "According to class, the seroprevalence of T. gondii was significantly higher in adults (≥ 1 year) (p<0.05) in conjunction with previous studies (Figliuolo et al. 2004; Rossi et al. 2011) indicating that horizontal transmission of sporulated oocysts by ingestion seems to be a main route of infection. In addition, the prevalence in females (20 %) were significantly higher than in males (6 %) (p<0.05) with seroprevalence rate of 3.37 (IC 95% , 1.75 to 6.48). "
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    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.
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