Seroprevalence of Antibodies against Highly Pathogenic Avian Influenza A (H5N1) Virus among Poultry Workers in Bangladesh, 2009

Sharifa Nasreen,A S M Alamgir,Katharine Sturm-Ramirez,Stephen P Luby,Jacqueline M Katz,Mahmudur Rahman,Kathy Hancock,Vic Veguilla,Timothy M Uyeki,David Wang,Salah Uddin Khan,Eduardo Azziz-Baumgartner,Emily S Gurley

doi:10.1371/journal.pone.0073200

Abstract

We conducted a cross-sectional study in 2009 to determine the seroprevalence and risk factors for highly pathogenic avian influenza A (H5N1) [HPAI H5N1] virus antibodies among poultry workers at farms and live bird markets with confirmed/suspected poultry outbreaks during 2009 in Bangladesh. We tested sera by microneutralization assay using A/Bangladesh/207095/2008 (H5N1; clade 2.2.2) virus with confirmation by horse red blood cell hemagglutination inhibition and H5-specific Western blot assays. We enrolled 212 workers from 87 farms and 210 workers from three live bird markets. One hundred and two farm workers (48%) culled poultry. One hundred and ninety-three farm workers (91%) and 178 market workers (85%) reported direct contact with poultry that died during a laboratory confirmed HPAI H5N1 poultry farm outbreak or market poultry die-offs from suspected HPAI H5N1. Despite exposure to sick poultry, no farm or market poultry workers were seropositive for HPAI H5N1 virus antibodies (95% confidence interval 0–1%).

Highlights

Pathogenic avian influenza (HPAI) A [Highly pathogenic avian influenza (HPAI) H5N1] virus was first identified among poultry in Bangladesh in March 2007 [1]
Despite extensive direct and close exposure to poultry at both farms and markets, we did not find any serologic evidence of HPAI H5N1 clade 2.2.2 virus infection among the serum samples collected from either farm or market poultry workers during the study period
Our results are similar to other HPAI H5N1 virus antibody seroprevalence studies conducted among poultry workers such as in Nigeria [10], Indonesia [17] and Vietnam [18] where no serologically confirmed infections were observed

Summary

Introduction

Pathogenic avian influenza (HPAI) A [HPAI H5N1] virus (clade 2.2.2) was first identified among poultry in Bangladesh in March 2007 [1]. As of 29 April 2013, 549 commercial and backyard poultry farms had confirmed HPAI H5N1 outbreaks across 51 out of 64 districts [2]. The first human case of HPAI H5N1 virus infection in Bangladesh was identified in a child during 2008 through routine community surveillance for influenza in Dhaka. Risk factors for avian-to-human transmission of HPAI H5N1 virus include direct or close contact with sick or dead infected poultry, or visiting a live bird market [4,5,6]. Poultry sellers who handle live poultry, and slaughter, defeather or eviscerate chickens without the use of any personal protective equipment may have occupational exposure to HPAI H5N1 virus

Methods

Results

Conclusion