Zoonotic Gastrointestinal Nematodes (Trichostrongylidae) from Sheep and Goat in Isfahan, Iran

Background: The most important genera of trichostrongylid nematodes that live in digestive tract of ruminants include Teladorsagia, Haemonchus, Trichostrongylus, Cooperia and Marshallagia. Out of the above-mentioned genera, four infect humans including Teladorsagia, Haemonchus, Trichostrongylus and Marshallagia. These parasites are an important part of ruminant pathogens, and some are extremely pathogenic and deadly, and thus vitally important from veterinary viewpoint. Hence, this study was performed to determine the latest status of zoonotic gastrointestinal trichostrongylid nematodes in sheep and goat, in Isfahan province, center of Iran. Materials, Methods & Results: The intestines and abomasums of 109 small domestic ruminants (56 sheep and 53 goats) which were slaughtered at Isfahan slaughterhouses were collected and placed separately in large containers to be transferred to the laboratory. To investigate morphological characteristics, the found nematodes were placed on glass slides appropriately, dyed by lactophenol and azocarmine as a temporary mount. Finally, their genus and species were identified according to morphological characteristics using valid taxonomic keys. Seven species of trichostrongylid nematodes belonged to four genera were isolated from intestines and abomasums of sheep and goats. The found species were Trichostrongylus vitrinus, T. probulurus, T. colubriformis, Teladorsagia occidentalis, T. circumcincta, Marshallagia marshalli and Haemonchus contortus. The dominant species in the intestines of sheep and goats was T. vitrinus with the frequency of 26.8% and 18.9%, respectively. In the abomasums of sheep, the dominant species was M. marshalli with the frequency of 57.1%, and that in goats was the species T. circumcincta with the frequency of 47.2%. Discussion: Livestock has undeniable role in the human life cycle and ecosystem balance. At times, coexistence of humans alongside livestock over the years has been accompanied by undesirable consequences like zoonotic diseases. According to the results of this study, infection of livestock with trichostrongylid nematodes is well established in Isfahan region. In this study, seven species of trichostrongylid nematodes were found in animals under study. Among those, T. vitrinus, T. colubriformis, T. probulurus, M. marshalli and H. contortus are zoonoses and therefore their control and prevention have been always a main problem in hyperendemic and endemic areas. Unfortunately, no study has been performed on human in any regions of Iran in recent years regarding prevalence of zoonotic gastrointestinal helminthes such as trichostrongylid nematodes. Hence, trichostrongylid nematodes in human in the area, if any, can be considered as neglected parasites. Moreover, some of the found parasites, namely T. colubriformis, T. circumcincta, H. contortus, are resistant to several medications. Given that these parasites have a direct life cycle, thus, lack of hygiene in farms where animals are kept leads to increased infection. To reduce infection, protect livestock, and increase production in endemic areas, it is recommended that drug resistance in the found species should be evaluated and livestock should be periodically treated with anthelmintic medications. Additionally, because of zoonotic nature of some species of the parasites, measures must be taken to protect the health of people who are directly engaged with these animals.