Comprehensive Analysis of Morphologic and Molecular Studies on Eimeria tenella Infection in Broiler Chicks in Sulaimani Province, Iraq.

Coccidiosis is a major parasitic disease that affects domestic fowl, turkeys, ducks, and geese around the world. It is caused by protozoan parasites of the phylum Apicomplexa originating from the genus Eimeria. This study was recommended due to the lack of data on chicken Eimeria species in the Kurdistan region. There are nine recorded species of Eimeria in chickens, E.tenella is the most common coccidia in poultry, which is distinguished by its easily identifiable injuries and significant losses in early broilers and pullet layers. The research examined naturally infected broiler chicks aged between 3 and 6 weeks with Eimeria tenella. The samples were taken from caecal content and examined by standard methods such as necropsy and microscopic examinations. Microscopic examination revealed a large number of coccidian oocysts in the caecal content. Histopathological analysis showed severe sloughing of the lining mucosa with haemorrhage and necrosis, along with the presence of different stages of Eimeria, including oocytes, macrogametes, microgametes and schizonts in the submucosal layer. Haematoxylin and eosin staining facilitated a histopathological study on the affected caecum tissue. The study highlights an important stage that streamlines parasite isolation for molecular diagnosis by directly using cecum samples for DNA extraction. This method allows molecular diagnostic procedures to be completed more efficiently, regardless of the parasite’s stage.