Are Poultry or Wild Birds the Main Reservoirs for Avian Influenza in Bangladesh?

Mohammad Mahmudul Hassan,Marcel Klaassen,Md Ahasanul Hoque,Nitish Chandra Debnath,Mat Yamage

doi:10.1007/s10393-017-1257-6

Abstract

Avian influenza viruses (AIV) are of great socioeconomic and health concern, notably in Southeast Asia where highly pathogenic strains, such as highly pathogenic avian influenza (HPAI) H5N1 and other H5 and H7 AIVs, continue to occur. Wild bird migrants are often implicated in the maintenance and spread of AIV. However, little systematic surveillance of wild birds has been conducted in Southeast Asia to evaluate whether the prevalence of AIV in wild birds is higher than in other parts of the world where HPAI outbreaks occur less frequently. Across Bangladesh, we randomly sampled a total of 3585 wild and domestic birds to assess the prevalence of AIV and antibodies against AIV and compared these with prevalence levels found in other endemic and non-endemic countries. Our study showed that both resident and migratory wild birds in Bangladesh do not have a particularly elevated AIV prevalence and AIV sero-prevalence compared to wild birds from regions in the world where H5N1 is not endemic and fewer AIV outbreaks in poultry occur. Like elsewhere, notably wild birds of the orders Anseriformes were identified as the main wild bird reservoir, although we found exceptionally high sero-prevalence in one representative of the order Passeriformes, the house crow (Corvus splendens), importantly living on offal from live bird markets. This finding, together with high sero- and viral prevalence levels of AIV in domestic birds, suggests that wild birds are not at the base of the perpetuation of AIV problems in the local poultry sector, but may easily become victim to AIV spill back from poultry into some species of wild birds, potentially assisting in further spread of the virus.

Highlights

Avian influenza is one of the most potent zoonotic diseases affecting poultry, but some strains can have the potential to affect wildlife and human health (Bahl et al.Are Poultry or Wild Birds the Main Reservoirs for Avian Influenza in Bangladesh? 4912016; Peiris et al 2007), with the always looming potential of a pandemic of H1N1 Spanish Flu dimensions
Our data for Bangladesh suggest very high prevalence of Avian influenza viruses (AIV) and AIV antibodies in some domestic bird groups and somewhat elevated values in wild birds when compared with data from wild birds in areas where highly pathogenic avian influenza (HPAI) H5N1 is not endemic
For Bangladesh, considering the need to avoid AIV infections in domestic birds for poultry and human health concerns, it is remarkable that AIV antibody prevalence among domestic birds was higher than in wild birds

Summary

Introduction

Avian influenza is one of the most potent zoonotic diseases affecting poultry, but some strains can have the potential to affect wildlife and human health (Bahl et al.Are Poultry or Wild Birds the Main Reservoirs for Avian Influenza in Bangladesh? 4912016; Peiris et al 2007), with the always looming potential of a pandemic of H1N1 Spanish Flu dimensions. In as many as nine countries in Southeast Asia, the Middle East and North Africa, HPAI H5N1 [Goose/Guangdong/1/1996 (Gs/GD)] is considered endemic adding to its economic impact and its health risk to local wildlife and human health (Olsen et al 2006; Peiris et al 2007). These threats continue to demand studies that identify the causes for the emergence and spread of AIV and methods for its containment

Methods

Results

Conclusion