Prevalence of Linguatula Serrata Nymphs and Pathological Lesions of Infected Mesenteric Lymph Nodes among Ruminants in Kermanshah, Western Iran

Linguatulosis is one of the important zoonotic diseases that cause public health problems worldwide. This study was carried out from March 2014 to February 2015 to estimate the prevalence of nymphal stages of Linguatula serrata in ruminants of different sex and age slaughtered at the Kermanshah municipal abattoir, in western Iran. For this purpose, the mesenteric lymph nodes (MLNs) were examined grossly and three MLNs for each animal were collected for parasitological and pathological studies. Of the total of 456 sheep (252 ♂ and 204 ♀), 390 goats (215 ♂ and 175 ♀) and 412 cattle (255 ♂ and 157 ♀), 90 (19.7%), 98 (25.1%) and 53 (12.8%) were infected with nymph stages of L. serrata, respectively. A significant difference in the prevalence of linguatulosis was observed among studied animals (P<0.05) and the highest and lowest prevalence were detected in goats and cattle, respectively. Prevalence of L. serrata nymphs in males and females was not significantly different (P>0.05). The prevalence increased with age (P<0.05). Grossly, the infected MLNs were enlarged, and their cross-sectional areas were coarse, firm, granulated, oedematous, and red in colour. Necrosis, oedema, haemorrhages, depletion of the lymphocytes and granulomatous reactions which are characterised by infiltration of mononuclear inflammatory cell around the parasite were the main histopathological lesions. These results indicated the high prevalence of L. serrata infection in livestock animals in Kermanshah. Furthermore, this study provides a preliminary baseline data for the future monitoring of this potentially important parasitic disease. The potential importance of these findings to human health is discussed.