Comparative pathophysiological impact of Eimeria spp. infection in four avian species: A biochemical, haematological, and histological study

Objective: Intestinal coccidiosis caused by Eimeria spp. represents a major parasitic disease affecting poultry and other avian species, leading to significant economic and health impacts. This study aimed to assess the biochemical, immunological, haematological, and histopathological alterations associated with Eimeria infection in four bird species: chicken, chicken rose, duck, and pigeon. Methods: A total of 191 intestinal samples were microscopically examined, and biochemical parameters (AST, ALT, MDA, GSH), cytokine levels (IL-10), and blood indices (RBC, WBC) were measured. Histological sections from the duodenum, cecum, and mid-intestine were analysed using H&E staining to evaluate tissue damage. Results: Overall infection prevalence reached 62.3%, with no significant difference among species (P = 0.577). Infected birds showed markedly elevated oxidative stress markers (AST, ALT, MDA), increased IL-10 levels, and significant haematological shifts, including leucocytosis and anaemia. Histologically, infected tissues exhibited severe pathological lesions such as villous atrophy, epithelial sloughing, inflammatory infiltration, and presence of parasitic cysts, with variable severity among species. Conclusion: Eimeria spp. infection induces systemic and local alterations in affected birds, reflected in biochemical imbalances, immune activation, and histopathological damage. These findings underscore the importance of integrated diagnostic approaches that combine molecular, serological, and histological methods to improve detection, prevention, and control of coccidiosis in avian hosts.