A survey of Linguatula serrata infection in sheep in Tabriz abattoir, East Azarbaijan Province

Linguatula serrata is an aberrant arthropod of the class Pentastomida. The adult parasite is found in the nasopharynx of canids. The larval form occurs in the mesenteric lymph nodes of herbivores including sheep in which it develops to the infective nymphal stage. This study was carried out from April 2009 to march 2010 to evaluate the infection rate of Linguatula serrata in 420 sheep which have been slaughtered in Tabriz abattoir. Samples of lymph nodes and livers were examined macroscopically and microscopically. Mesenteric lymph nodes of 162 sheep (38.57%), mediastinal lymph nodes of 43 sheep (10.23%) and livers of 4 sheep (0.71%) were infected with Linguatula serrata nymphs. Results showed that the infection rate increased with ageing (P<0.05). The results also revealed that the infection rate to the nymphs of parasite in black-colored lymph nodes were significantly (P < 0.05) higher than the infection rate in normal-colored nodes. No significant difference was observed between the infection rate in different seasons (P>0.05). Human can be infected through consumption of raw or under-cooked liver and visceral organs of sheep, hence the importance of inspection at slaughter houses needs to be emphasized.