Frequency of Trichostrongylus species and other Trichostrongylids in ruminants slaughtered in Hamadan slaughter house in 2020

Background and purpose: Zoonotic intestinal parasites and intestinal nematodes of livestock are indirectly one of the human health challenges in developing countries. Considering the possible role of gastrointestinal parasites in domestic animals in the transmission of infection to humans, their economic significance in the production of protein products, and the lack of up-to-date information on the contamination status of ruminants in the region, the present study aimed at determining the frequency of Trichostrongylus species in ruminants slaughtered in Hamadan slaughterhause in 2020. Materials and Methods: Abomasum‎ and intestinal samples were taken from 338 livestock by referring to Hamedan slaughterhouse. The samples were placed separately in sealed containers and transferred to the parasitology research laboratory of Hamadan University of Medical Sciences to diagnose parasitic infection. After opening and washing the contents of the samples in a large tray, these contents were filtered through a wire sieve several times and the obtained transparent material was gradually poured into other trays. Then, the worms were separated with the help of a hand-held magnifying glass and the light of the study lamp and were placed within bottles containing alcohol-glycerin. The worms were then identified at the genus and species levels using diagnostic keys. Information about livestock such as sex, type of livestock, anatomical position, and habitat were recorded in the information form. Data were analyzed using descriptive statistics, and the results were presented as tables and graphs. Results: Out of 338 livestock, 70 (20.70%), 264 (78.10%), and 4 (1.18%) were Cattles, sheep, and goats, respectively. In addition, 240 (71%) and 98 (28.99%) livestock were male and female, respectively. 301 (89.05%) and 37 (10.94%) livestock were young and old, respectively. The highest percentage of infected specimens was related to Ostertagia Ostertagi (64 cases, 48.5%) and the lowest percentage of infected specimens was related to male Nematodirus filicollis (1 case. 1.6%). Most of the infestations were reported for the male livestock and from those raised in Qorveh area. In addition, no worm infestation was observed in Cattles and goats.  Conclusion: Ostertagia infection was highly prevalent in the studied livestock. The zoonosis Trichostrongylus parasite was not observed in this study. The prevalence of intestinal nematodes in sheep in this region is still significant and should be planned to be controlled by the relevant authorities.