Prevalence and molecular analysis of Sarcocystis species infection in slaughtered cattle in Alborz, Iran

Abstract

Several species of Sarcocystis as an obligatory intracellular protozoon have been identified in cattle, including Sarcocystis cruzi, Sarcocystis hirsuta, and Sarcocystis hominis, whose definitive hosts are canids, felids, and humans respectively; these zoonotic parasitic species impose a financial and health burden on the livestock industry annually. The aim of the present study, which was conducted for the first time in Alborz province, was to determine the species of Sarcocystis based on macroscopic observation, digestion method and restriction fragment length polymorphism (RFLP)-PCR in slaughtered cows in this province in order to complete the information puzzle of the prevalence of Sarcocystis species in Iran and the world cattle.

In the present cross-sectional study, totally 138 samples of slaughtered cows in Alborz province industrial slaughterhouses were collected from diaphragm muscles and examined by macroscopic, digestive and molecular PCR-RFLP methods. This molecular-based method uses variations in homologous DNA sequences (polymorphism) of a population or species or to determine the precise locations of genes in a sequence. Fifty samples were randomly selected for DNA extraction and molecular analysis and sequencing for species identification. Macroscopic examination of the samples showed no cysts, but according to the digestion test results, 100 % of the samples were infected with Sarcocystis microcysts. The results of electrophoresis of PCR products showed a band of about 930 bp. The PCR products were digested with restriction enzyme (BFaI) and their digested pattern was evaluated. The results showed that all 50 samples were infected with Sarcocystis. After enzymatic digestion of primary PCR products, it was found that (47/50) 94 % and (3/50) 6 % the samples were infected with S. cruzzi and S. hirsuta species, respectively. No infection was found with S. hominis. Cattle slaughtered in Alborz province are highly infected with the Sarcocystis parasite, which can affect public health and animal health. The present study suggests that Sarcocystis spp. should be diagnosed by relying on high-precision diagnostic methods in order to improve food safety.