Effect of age, sex, and season on the prevalence of Linguatula serrata infestation in mesenteric lymph nodes of goats slaughtered in Tabriz, Iran

This research was conducted to determine the prevalence and intensity of infection with nymphs of Linguatula serrata in mesenteric lymph nodes of the goats from northwest of Iran. Moreover, the intensity of infection of mesenteric lymph nodes was compared based on gross appearance and the morphological changes in these nodes. In addition, the effects of age, sex, and season on the prevalence of Linguatula serrata were assessed. In this study, mesenteric lymph nodes (n = 16,284) were randomly collected from 2132 goats slaughtered in the abattoir of Tabriz, Iran, from September 2013 to September 2017. The samples were categorized based on their gross appearance (color and consistency) and then were cut into small pieces and immersed in normal saline (0.9% NaCl) solution and left for 5 to 6 h to allow nymphs to come out from the tissue. The results showed that 1241 out of total 2132 (58. 2%) goats and 9282 out of total 16,284 mesenteric lymph nodes (57%) were infested with the nymphal stage of Linguatula serrata. It was also revealed that the infestation rate was age-dependent: as the goats grow older, the infestation increases. Further, the prevalence of Linguatula serrata nymphs in the mesenteric lymph nodes in various seasons was not significant (P > 0.05). The prevalence of infestation rate in female goats was significantly higher than of male goats (P < 0.05). Besides, the infestation rate in the black-colored lymph nodes (75.88%) was significantly (P < 0.05) higher than those of hemorrhagic nodes (54.94%) and normal-colored nodes (22.65%). Moreover, the infestation rate of nymphs in the soft lymph nodes (83.91%) was significantly (P < 0.05) higher than those in normal (21.85%) and hard (32.43%) lymph nodes. Given the fact that the Linguatula serrata is a zoonotic parasite; thus, the inspection process should be meticulously done in an abattoir, especially in areas where residents consume raw or under-cooked liver and/or visceral organs of herbivores.