Histologic changes of abomasum due to larvae and adult stages of nematodes in naturally infected Kurdish sheep in Ilam province, West of Iran

Nematodes infections in sheep abomasum are the importance of economic and public health throughout the world and Iran. The current study was aimed to study histopathologic changes due to larvae and adult stages of nematodes in abomasum of naturally infected Kurdish sheep. For this purpose, a total numbers of 240 abomasa of slaughtered sheep from Ilam industrial slaughterhouse (2018-2019) were randomly collected for gross lesions and microscopic observations. Nematodes were removed and identified based on morphological characteristics. For histologic observations, a cube piece of each abomasum tissue (1 × 2 × 2 cm3) were prepared and fixed in 10% buffered formalin. Then sections (6 μm) were prepared using microtome and stained with Hematoxylin and Eosin (H&E) to observe histologically by using light microscope. Of all examined abomasa, 66.7% (160/240) were infected with five species of adult nematodes including Marshallagia marshalli (43.65%), Ostertagia circumcincta (15.5%), Parabronema skrjabini (5%), M. occidentalis (2.5%), and Haemonchus contortus (0.04%). Histologically, there was hyperplasia and thickness of the mucosa and elongation of nodes with loss of parietal cells and replacement of mucous secreting cells. The severe infiltration of inflammatory cells, particularly Eosinophiles in parin connective tissue of mucosa and around the abomasal nodes as well as a few larvae sections elucidated chronic hypertrophic gastritis. From the results of histologic changes due to helminths infection in abomasa of examined sheep, it was concluded further studies are necessary to identify and decrease economic losses in the region.