ABSTRACT:
Infections caused by protozoa belonging to theSarcocystidae family have worldwide distribution and are common in ruminants, leading to considerable economic losses. This study evaluatesSarcocystis spp., Toxoplasma gondii andNeospora caninum infections in sheep from Southwest region of Rio Grande do Sul, Brazil. Myocardium samples of 80 sheep raised on extensive system were collected. Tissue cysts were detected by direct examination and presence of infective agents was confirmed by PCR. Macroscopic evaluation did not reveal changes, but direct microscopic examination showed cysts in 76.2% (61/80, 95% CI: 66.9 - 85.9) samples, and all cysts were morphologically similar to those caused by Sarcocystis tenella orSarcocystis arieticanis. PCR detectedSarcocystis spp. DNA in 21.2% (17/80, CI: 12.3-30.2) of the tested samples andT. gondii DNA in 15% (12/80, CI: 7.2-22.8). Moreover, 6.2% (5/80, CI: 2.1-13.9) samples contained DNA of both protozoan. The presence of N. caninum nucleic acids was not observed in tested samples. However, all PCR-positive samples (23.7%-19/80, CI: 14.4-33.1) were also positive by direct examination (microscopic cysts). Thus, a high occurrence of microscopic tissue cysts was detected in sheep from southwest region of Rio Grande do Sul State. Although PCR did not show good sensitivity to identify the causative agents of these cysts, it revealed the presence of Sarcocystis spp. andT. gondii in ovine cardiac muscle samples. This may predispose the contamination of animals and humans by these protozoa.
Key words:
Sarcocystis spp.; Toxoplasma gondii; Neospora caninum; PCR; diagnosis
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