Pathology, immunohistochemistry, and ultrastructural findings associated with neurological sarcocystosis in cattle

Molecular identification of four Sarcocystis species in cattle from Lithuania, including S. hominis, and development of a rapid molecular detection method

Background

Six Sarcocystis species are known to use cattle (Bos taurus) as the intermediate host, two of which, S. hominis and S. heydorni, are zoonotic. There is a need for a method that will enable rapid identification of the Sarcocystis species in cattle.

Methods

The diaphragm muscles of 102 cattle from Lithuania were examined for the presence of Sarcocystis spp., using two different methods for species identification. Individual sarcocysts were isolated from squash preparations of the diaphragm muscle under the light microscope, followed by genetic characterisation of excised cysts using sequence analysis of the 18S rRNA (18S rRNA) and cytochrome c oxidase subunit I (cox1) genes. The same cattle muscle samples were digested and species-specific PCR analyses targeting cox1 were developed to identify the Sarcocystis isolates to the species level.

Results

Under the light microscope, sarcocysts were detected in 87.3% of animals, and Sarcocystis infection was verified in all digested samples. Three species, namely S. cruzi (n = 20), S. bovifelis (n = 23) and S. hirsuta (n = 6), were identified by DNA sequence analysis of isolated sarcocysts. Based on sequence analysis of cox1, the level of genetic variability depended on Sarcocystis species and geographical location. Four Sarcocystis species, S. cruzi (96.1%), S. bovifelis (71.6%), S. hirsuta (30.4%) and S. hominis (13.7%), were confirmed in the digested samples. In individual samples, the most common finding was two species of Sarcocystis (44.1%), followed by three species (26.5%), a single species (24.5%) and four species (4.9%).

Conclusions

Although examination of tissue preparations under the light microscrope did not detect any sarcocysts belonging to S. hominis, this species was identified in the digested samples subjected to a cox1-specific PCR analysis. These results demonstrate the need for effective molecular diagnosis techniques to detect Sarcocystis spp., which may be present at a lower prevalence and not detectable among the limited number of sarcocysts identified individually under the light microscope.

Prevalence and histopathology of Sarcocystosis in slaughtered carcasses in southeast Iran

Objective

Sarcocystis spp. are common parasites and in terms of economics and pathogenicity in domestic animals is important. The purpose of this work was to define the rate of contamination of slaughtered carcasses of cattle to Sarcocystis using digestive and histopathological methods in southeast Iran.

Material and Methods

In this descriptive laboratory study for 1 year, 500 carcasses were examined and isolated bradyzoites of Sarcocystis with the digest method. Also, tissue samples from the esophagus and diaphragm were considered for pathologic studies and stained with hematoxylin and eosin of sections of histopathological.

Results

The results showed that the highest contaminations were in imported male animals aged 2-3 years old in the spring. There was a significant difference (p < 0.05) in the prevalence rate with the sex and race of cattle but no significant difference (p > 0.05) in the prevalence rate with age and season.

Conclusion

Infection with Sarcocystis is common in oxen in this region. The imported cattle are more infected. It seems that racing and the environmental condition affect the prevalence of Sarcocystosis.