Echinococcus spp. circulating in livestock in Serbia

Abstract

The echinococcosis case burden in the human population of Serbia is among the highest in Southeastern Europe, but comprehensive data on the circulating tapeworm species is scarce. To gain insight into the population genetics of Echinococcus spp. in Serbia, the project WORM_PROFILER will collect samples from livestock intended for human consumption at major abattoirs, slaughterhouses and homesteads over the next two years. During the first two months of sampling, 22 livers from pigs (n=15), lambs (n=5) and calves (n=2) with clearly identifiable cysts and/or cyst-like formations as well as scar tissue were collected from major abattoirs around the country. The cyst content and/or affected area was sampled by direct isolation using pipette tips and/or excision of the tissue and analyzed microscopically, followed by quick DNA extraction by boiling in 0.02 M NaOH for 15 min and amplification of the cox1 gene using primers which can differentiate E. granulosus, E. multilocularis and E. canadensis via conventional PCR. Several large cysts were present only in the liver of one boar. Tapeworm larvae were microscopically confirmed in the cysts’ content and later identified by PCR as E. granulosus. PCR analysis additionally revealed the presence of E. canadensis gDNA in a tissue sample from another pig from a different farm. Although these results indicate that most carcasses flagged for conditional use based on liver examination by abattoir veterinarians are not infected by Echinococcus spp., they nonetheless suggest that pigs may play an important role in its transmission in Serbia. Sequencing of the cox1 and nad1 genes from the samples in which Echinococcus spp. gDNA was detected is currently underway.