Distribution and epidemiological factors influencing Eimeria species occurrence in commercial chicken farms in Lagos State, Southwest Nigeria.

Eimeria parasites, the causative agents of coccidiosis, are among the most economically significant pathogens in the global poultry industry. Understanding their epidemiology is important for effective control. This study determined the prevalence and risk factors of Eimeria parasites in commercial chicken farms in Lagos State, Nigeria. Between July and October 2020, pooled faecal/litter samples were collected from 265 chicken flocks across 157 randomly selected farms in Lagos-East (LE) and Lagos-West (LW) senatorial districts. Samples were screened microscopically for oocysts and quantified using the McMaster technique (oocysts per gram: opg). A subset of 30 samples positive for oocysts were analysed by PCR for species identification. Farm structure, management, and biosecurity practices were assessed via semi-structured questionnaires. Eimeria spp. were detected in 58.6% (92/157) of farms and 47.5% (126/265) of flocks, with a mean oocyst load of 5.2 x 104 ± 2.2 x 105 opg. The most common species detected was Eimeria acervulina (100.0%, 30/30) while E. lata (3.3%, 1/30) and E. zaria (3.3%, 1/30) were present but least common. LE farms had lower odds of infection (OR: 0.2, P < 0.001) while those that housed multiple chicken types had a higher risk (OR: 5.0, P < 0.001). At flock level, increased risk was associated with birds aged 6-10 weeks and placing feed in cages. Birds in battery cages had significantly lower oocyst counts than those on deep litter (β: 108,769.4, P = 0.006). This study highlighted the high prevalence of Eimeria in chicken farms in Lagos State and provided insights for improved control.