Abstract

Сoccidiosis is a protozoan disease caused by Eimeria bateri (E. bateri), Eimeria tsunodai (E. tsunodai), Eimeria uzura (E. uzura), Eimeria tenella (E. tenella), Eimeria necatrix (E. necatrix), and Eimeria acervulina (E. acervulina). The goal of the current study was to explore the micropathology of the duodenum, jejunum, caecum, liver, lung, spleen, kidney, adrenal gland of Japanese quails naturally infected with. E. tenella. The histopathological examination revealed that developmental E. tenella led to the damage of caecal, duodenal, and jejunal. Necrosis and desquamation of the integumentary epithelium, atrophy of crypts and folds, hemorrhages, lymphoid infiltration were confirmed in the mucous membrane of these intestines. The main changes observed in the parenchymal organs involved the fatty dystrophy of hepatocytes and lymphoid infiltration of parenchyma of the liver, stagnant hyperemia and edema of the lungs; granular dystrophy and necrosis of epithelial cells of the collecting ducts of the kidneys, venostasis of blood sinusoids of the spleen, hyperplasia of interrenal tissue, and dystrophia of suprarenal tissue of the adrenal gland. Morphometric studies have shown that pathological changes in the organs of quails infected with E. tenella led to a decrease in the thickness of the caecal mucosa, volume of the parabronchial lumen of the lung, and the number of renal corpuscles of the infected group, compared to the control group. The indicators of the interrenal-adrenal index of the adrenal glands, the number of clusters of lymphoid cells of the liver, and lymphoid nodules of the spleen increased. The received information could offer deep insights about pathogens in quails coccidiosis and can be used for planning therapeutic measures.