Epidemiological Assessment of Hygienic Conditions of Live Bird Markets on Avian Influenza In Chittagong Metropolitan City, Bangladesh

Abstract

Live Bird Market (LBM) is a place where live bird traders and consumers are interacted in respect to live bird trading. The environment of LBM might be contaminated with various infectious diseases like Avian Influenza Virus. No systematic study has previously been attempted for investigation of Avian Influenza status in LBM which could pose threats to the economy and public health. Therefore, a cross sectional study was conducted on hygienic status and Avian Influenza in LBMs under Chittagong Metro in Bangladesh. The overall objective of the study was to assess the LBM demographic information and hygienic status in contrast with AI prevalence followed by subtype distribution and associated risk factors. A total of 290 pooled environmental samples along with questionnaire based identity information, participant’s demography, market structure followed by management and hygienic status based data were obtained from 290 stalls under 40 different LBMs. At each stall swab samples were collected from up to 9 different sites. The samples were evaluated by Real time Reverse Transcriptase Polymerase Chain Reaction (rRT-PCR) for detection of M gene followed by subtypes of H5, H7 and H9. Three quarters of poultry stalls were retail type where the birds were aggregated from multiple sources. Most of the stalls were closed together. There was no space provisioned for sick birds, however the stalls had access to resident wild birds. Around one third of stalls’ floor was constructed using mud and more than 50% stalls used only water for cleaning the stalls. Stall vendors had predominantly I-IX level of education. The vendors had slaughtered their poultry within the stalls and the unsold birds were allowed to stay overnight in the stall for next day selling. The wastes were generally disposed into open dustbin, drain, water bodies and beside the highway or another open space. The prevalence of AIV in LBM was 40% (95% CI: 20-60%; N=40) whereas the prevalence of avian influenza was 20.3% (95% CI: 10-30%, N=290) at stall level. Again, the prevalence of H5, H7 and H9 at stall level was 2.8% (95% CI: 1-5%), 0% Page | xiii and 3.1% (95% CI: 1-6%), respectively. The prevalence of un-typed AIV was 15.2% (95% CI: 10-19%). Fisher’s exact test followed by Generalized Estimating Equation was applied to identify potential risk factors associated with Avian Influenza in LBMs. Selling of species (OR=2.5: Chicken and non-duck species versus Duck with other species.), Bird holding area (OR=1.9: Cage versus Floor) and Hygienic score (OR=3.1: Score 3 or more versus score less than 3) were identified as the risk factors for AI in LBMs. The present study has been identified the risk factors associated with the occurrence of AIV at stall level of LBMs. Knowledge obtained from this study could provide new understanding of the distribution and transmission of AI through LBM in Bangladesh. The findings could be used to develop a proof based programme concerning environmental sanitation along with development of a strong surveillance system to reduce the AI transmission through LBMs in Bangladesh.