Prevalence of Coccidiosis in Commercial Chickens of Bangladesh: Species Identification with Age and Seasonal Associations

Coccidiosis is one of the most economically significant diseases in the poultry industry, resulting in substantial economic losses through treatment costs, reduced growth rates, and decreased body weight gain. The present study aimed to determine the prevalence of different Eimeria (E.) species in commercial chickens and to assess age-specific and seasonal patterns of coccidiosis. A total of 595 chicken fecal samples were randomly collected from three different chicken types, namely broiler breeds (n = 227), layer breeds (n = 205), and Sonali (a dual-purpose crossbred, n = 163) chickens between April 2022 and March 2023, across 27 different farms in the Pirojpur district of Bangladesh. The farms were selected for sampling based on the presence of chickens having clinical signs such as diarrhea, decreased feed consumption, impaired weight gain, lameness, and increased mortality. After sacrificing the suspected chickens, the intestine was carefully inspected and examined for gross pathological lesions. Mucosal scrapings from different intestinal segments and fecal samples were analyzed microscopically for the presence of oocysts using standard parasitological methods. The identification of different Eimeria species was conducted based on the morphological and morphometric characteristics of the oocysts. The result revealed that the overall prevalence of coccidiosis was 13.78%. Among the chicken types, Sonali demonstrated the significantly highest prevalence (21.47%), followed by layers (13.66%) and broilers (8.37%). Five different Eimeria species were identified, with E. tenella (45.12%) being the most prevalent, followed by E. acervulina (18.29%), E. maxima (15.85%), E. brunetti (10.98%), and E. necatrix (9.76%). No significant influence of age or season on coccidiosis prevalence was observed in broiler and layer chickens. In Sonali chickens, the prevalence of coccidiosis increased significantly with age, while no significant effects of season were observed. It has been concluded that the total prevalence of coccidiosis was 13.78%, with Sonali chickens exhibiting the highest prevalence. Five distinct species of Eimeria were identified, with E. tenella being the most common species. Furthermore, no effects of season and age on prevalence of Eimeria species were observed, except for Sonali chickens, where the prevalence increased with age.