FLOCK LEVEL PREVALENCE AND DETERMINANTS OF CHICKEN COCCIDIOSIS IN SYLHET DISTRICT

Abstract

The sub-tropical climatic condition and suitable weather of Sylhet district favour the occurrence and endemicity of chicken coccidiosis, however, the epidemiological estimates of this disease were scarce. Thus, a study was carried out to measure flock level prevalence as well as determinants of chicken coccidiosis in Sylhet district. A cross-sectional study was conducted consisting of 430 pooled faecal samples randomly collected from 12 upazilas of Sylhet district to estimate the prevalence. Collected faecal samples were examined by simple McMaster technique using saturated salt and sugar solution to quantify the load of oocysts of different species of Eimeria. If a gram of faeces contained ≥ 50 oocysts of one or more Eimeria species i.e. ≥ 1 oocysts in McMaster slide, then the flock was considered to have coccidiosis. Prevalence was calculated as the proportion of coccidiosis positive flocks among the sampled flocks. Case-control studies were conducted using the results of prevalence study to determine the determinants of coccidiosis at flock level. Multivariable logistic regression analysis was used to identify the plausible determinants. The overall flock prevalence was 64.19% and typewise flock

prevalence was the highest in backyard (72.94%) followed by in layer (65.48%) and the lowest in broiler (48.44%). The most and least prevalent upazilas were Balaganj (90.48%) and Kanaighat (36.36%), respectively. Among the eight identified Eimeria species (Eimria mitis, E. tenella, E. necatrix, E. acervulina, E. hagani, E. maxima, E. brunetti and E. praecox), the highest prevalence was found for E. mitis (43.49%) whereas the lowest for E. praecox (3.02%). The prevalence of single and mixed infection was 13.26% and 50.93%, respectively and in case of single infection, the highest prevalent species was E. tenella (5.35%), while lowest in E. acervulina (0.23%). In case of species-wise prevalence by flock type, E. mitis was dominant species in both backyard (55.50%) and layer (44.05%), while E. tenella in broiler (40.63%) and E. praecox was the lowest in all types. The statistically significant (p < 0.05) determinants were flock type, cannibalism and presence of litter in overall coccidiosis; whereas flock size and presence of litter in backyard; age of flocks and empty resting period in broiler; age of flocks and bio-security in layer and flock type, flock size, prophylactic use of anti-coccidial drug and periodical turning of litter in case of mixed infection. The results of this study clearly state that chicken coccidiosis is very common problem in this district and the reason of headache of the poultry farmers and the findings of this study can be reliably used for planning and policy making for adoptive surveillance, prevention and control measures of this economically important disease. However, further researches are still needed using advanced serological and molecular techniques to discover other epidemiological parameters like host and vector ranges, spatial and temporal trends, mathematical modelling for dynamicity and ecological determinants analysis.