Biosecurity and Circulation of Influenza A (H5N1) Virus in Live-Bird Markets in Bangladesh, 2012

Abstract

Bangladesh has been considered as one of the five countries endemic with highly pathogenic avian influenza A subtype H5N1 (HPAI H5N1). Live-bird markets (LBMs) in south Asian countries are believed to play important roles in the transmission of HPAI H5N1 and others due to its central location as a hub of the poultry trading. Food and Agriculture Organization (FAO) of the United Nations has been promoting improved biosecurity in LBMs in Bangladesh. In 2012, by enrolling 32 large LBMs: 10 with FAO interventions and 22 without assistance, we assessed the virus circulation in the selected LBMs by applying standard procedures to investigate market floors, poultry stall floors, poultry-holding cases and slaughter areas and the overall biosecurity using a questionnaire-based survey. Relative risk (RR) was examined to compare the prevalence of HPAI H5N1 in the intervened and non-intervened LBMs. The measures practised in significantly more of the FAO-intervened LBMs included keeping of slaughter remnants in a closed container; decontamination of poultry vehicles at market place; prevention of crows' access to LBM, market/floor cleaning by market committee; wet cleaning; disinfection of floor/poultry stall after cleaning; and good supply of clean water at market (P < 0.05). Conversely, disposal of slaughter remnants elsewhere at market and dry cleaning were in operation in more of the FAO non-intervened LBMs (P < 0.05). The RR for HPAI H5N1 in the intervened and non-intervened LBMs was 1.1 (95% confidence interval 0.44-2.76), suggesting that the proportion positive of the virus in the two kinds of LBM did not vary significantly (P = 0.413). These observations suggest that the viruses are still maintained at the level of production in farms and circulating in LBMs in Bangladesh regardless of interventions, albeit at lower levels than in other endemic countries.

A large-scale study of a poultry trading network in Bangladesh: implications for control and surveillance of avian influenza viruses

“…The high level of contamination of Bangladeshi LBMs with a variety of AIV strains [49][50][51][52][53] and the association between LBM density and the risk of HPAI H5N1 outbreaks in Bangladeshi farms [18] suggests that AIV surveillance and control programmes implemented in LBMs could be effective for reducing disease risk for the production sector, as well as for humans. Furthermore, the position of nodes, either live animal markets or farms, in networks of potentially infectious contacts has been associated with their roles in the spread of pathogens [14,54].…”

“…However, even if a small number of LBMs is to be targeted, the effective implementation of such control strategies may prove challenging. Although poor hygiene in Bangladeshi LBMs was associated with a higher likelihood to detect AIVs in one study [52], studies have shown that only a limited number of biosecurity measures have been implemented in LBMs so far [49,59]. Furthermore, one study revealed that those limited changes had not been sufficient to reduce the level of AIV contamination in LBMs with better biosecurity measures compared to LBMs with less or no biosecurity measures in place [49].…”

Incidence of contamination of live bird markets in Bangladesh with influenza A virus and subtypes H5, H7 and H9

“…As of June 2016, no official outbreak report attributed to the virus could be seen on the OIE's new World Animal Health Information System (WAHID) except for a notification made on 15 February 2016 of the identification of the virus in 40 dead house crows ( Corvus splendens ) (http://tinyurl.com/zj82f9c). On the other hand, low‐pathogenic avian influenza (LPAI) H9N2 was reported from the country in several studies (Biswas et al., , ; Gerloff et al., ; Negovetich et al., ; Shanmuganatham et al., ). Low‐pathogenic avian influenza H7N9 was predominantly reported from China (Gilbert et al., ).…”

A cross-sectional study to quantify the prevalence of avian influenza viruses in poultry at intervention and non-intervention live bird markets in central Vietnam, 2014

“…Live bird markets (LBMs) are known to be reservoirs and transmission hubs for avian influenza viruses (AIVs) (Biswas et al., ). In South‐East Asian countries, LBMs are ubiquitous and integral components of the semi‐intensive poultry industries that are common in this part of the world (Indriani et al., ; Wan et al., ).…”

“…In LBMs, it is common for a range of subtypes of AIV to be mixed as a result of different poultry types and species being brought together from different geographical locations (Li et al., ). In South‐East Asia, highly pathogenic avian influenza (HPAI) viruses are known to circulate in LBMs (Biswas et al., ; Indriani et al., ; Nasreen et al., ; Nguyen et al., ; Phan et al., ) and it has been hypothesized that LBMs may facilitate the emergence and spread of new viral reassortants due to close contact amongst the infected birds (Zhou et al., ). Furthermore, it has also been shown that in China, human infections with AIV, in particular, of the subtypes H5N1 and H7N9 are associated with recent exposure to poultry in LBMs (Li et al., ; Wan et al., ).…”