Prevalence of Sarcocystis spp. in Argentinean cattle

Departamento de Epizootiología y Salud Pública, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, 60 y 118, 1900 La Plata, Argentina.
Veterinary Parasitology (Impact Factor: 2.46). 12/2010; 177(1-2):162-5. DOI: 10.1016/j.vetpar.2010.11.036
Source: PubMed


Sarcocystis cruzi, S. hirsuta and S. hominis are apicomplexan parasites that affect cattle worldwide with variable prevalence. The aim of the present study was to evaluate the prevalence of Sarcocystis spp. in Argentinean cattle comparing microscopic fresh examination and molecular methods. Blood, myocardium and loin samples were collected in five slaughterhouses from a total of 380 bovines. Origin of animals was representative of the major beef cattle production area of Argentina. Samples were analyzed by fresh microscopical examination, transmission electron microscopy (TEM), IFAT and PCR-RFLP. Thin walled sarcocysts corresponding with S. cruzi were found in 99.5% of heart samples. Sarcocysts were detected in 73.1% of loin samples; 71.5% had S. cruzi cysts and 23.1% had thick walled sarcocysts (S. hirsuta or S. hominis). TEM observation revealed the presence of characteristic S. hominis and S. hirsuta cyst walls in 7 and 1 loin samples respectively. Using IFAT, 379/380 animals had titers 25 or higher, showing a full agreement with fresh examination. Amplification products were detected in 35.5% (135/380) of loin samples; however Sarcocystis species could only be determined by RFLP in 29 samples. Agreement between fresh examination and PCR was low (Kappa value=0.262). This is the first report of S. hominis and S. hirsuta in Argentina. Further studies are needed to improve the sensitivity of molecular methods for species identification, especially for differentiation of S. cruzi and S. hirsuta from the zoonotic species S. hominis. The results of the present study and others focusing on sensitivity and specificity of Sarcocystis spp. diagnostic methods should contribute to improve food safety.

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    • "Sarcocystis spp. cystozoites were obtained from naturally infected bovine hearts and were purified according to a previously described procedure (Moré et al., 2011). Briefly, 100 g of minced myocardium were mixed with 400 ml of digestion solution (2.5% pepsin, 1% HCl) and were placed in a magnetic stirrer for 20 min at 37 • C. The suspension was filtered through 300, 150, and 53 m sieves into 50 ml centrifuge tubes and centrifuged at 500 × g for 5 min and it was centrifuged at 500 × g for 5 min. "
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    • ") 82.4% in the cattle in Australia (Savini et al., 1992), 97.0% in sheep, 97.4% in goat and 97.8 % in cattle in Iraq (Latif et al., 1999), 96.9% in sheep and 90.0% in cattle in Mongolia (Fukoyo et al., 2002), 99.5% in cattle in Argentina (More et al., 2011) 100% in sheep and 94.7% in cattle in Iran (Hamidinejat et al., 2010; Dehaghi et al., 2013). The low prevalence of sarcocystosis in meat producing animals in Malaysia in comparison with other countries could be attributed to the low population of stray dogs. "
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    • "It is therefore highly likely that the animals were in contact with their natural environment and had ingested tissue of potential IHs of Sarcocystis spp. that got infected via food or water contaminated with sporocysts from the feces of python snakes. A predator–prey relationship is much more likely for free-living animals or farm-bred animals reared under extensive conditions (Dubey et al. 1989; McAllister et al. 1995; Moré et al. 2011). As the 'farmers' officially declared, to regulatory authorities, that they breed all rodents used as food for the snakes themselves, and based on the facility conditions, where a direct contact of the snakes with wild rodents can be excluded, it seems unlikely that the infected snakes had been legally bred. "
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