Characteristics of Deshi chicken and Duck Trading Patterns and their Impact on Zoonotic Disease Transmission

Abstract

Live bird markets (LBMs) may function as hubs for the dissemination of pathogens and thus a potential source of avian influenza. Under a cross-sectional study 22 stallholders and 40 middlemen were selected and interviewed from two wholesale LBMs in Chittagong City Corporation (CCC), in order to describe the flow of deshi chickens and ducks and to assess the risk of release of avian influenza viruses (AIVs) in 2 LBMs at CCC through deshi chickens and ducks trade. A total of 44 environmental pooled samples were collected from middleman storage facilities from outside of 6 LBMs in CCC. Real Time Reverse Transcriptase Polymerase Chain Reaction (rRT-PCR) was used to detect M gene then followed by H5 and H9 subtypes in order to determine whether deshi chickens and ducks were infected by AIVs prior to their arrival at CCC LBMs. In the present cross-sectional study we found that most of the deshi chickens were handled by 2 to 3 middleman and 1 or 2 either wholesaler or retailer. It was rarely found the involvement of 2 whole¬salers in the desi chickens transaction chain. In case of ducks transaction chain between farms and end customer is more likely that 1 to 2 middlemen and 1 whole¬saler or retailer were involved but did not find the involvement of 2 wholesalers in the transaction chain. Two main pathways (P1and P2) of release assess¬ment were identified for AIVs transmission. In pathway1 (P1) deshi chickens or ducks sold by farmers being infected at the farm gate, risk of release of AIVs to the susceptible poultry at LBMs in CCC was high, whereas in the pathway 2 (P2) of deshi chickens or ducks sold by farmers being not infected at the farm, but infected any step of the pathway (storage or transport) and arrives as infectious at CCC LBMs, risk of release of AIVs to the susceptible poultry at CCC LBMs was low, medium and high depending upon when and at which step of the pathway susceptible deshi chickens and ducks become getting infected in the transaction chain and dissemination of AIVs to the susceptible poultry at CCC LBMs. We found overall prevalence of AIV in the environmental sample sites was 26.3% for M gene, 19.5% for H5 and 12.8% for H9 (95% CI: N=44). The proportion of positive samples in the present study was identical (p- 0.81) to the results obtained from the BALZAC project cross sectional study. It was therefore likely that the poultry entering the LBMs may be already contaminated with AIVs. Knowledge from this study could provide a new under¬standing of the deshi chickens and ducks value chain and release of avian influenza through LBMs at CCC in Bangladesh. These findings could be used to develop a programme concerning biosecurity and hygienic management to reduce the risk of release of AIVs and spreading of avian influenza through LBMs in Bangladesh via deshi chickens and ducks trade.