A cross-sectional study of avian influenza in one district of Guangzhou, 2013.

Haiming Zhang,Zhiwei Zhou,Wutao Xiao,Riwen He,Ling Wang,Jiancui Zhu,Haibing Zhang,Dan Shen,Zhen Zhang,Mailing Hu,Hai Tan,Cong Peng,Lilan Zheng,Yuhua Chen,Wenhua Li,Guanghua Lan,Jianyu Yang,Jianxin Zhong ,Jun Hou ,Xuening Duan

doi:10.1371/journal.pone.0111218

Haiming Zhang, Zhiwei Zhou + Show 18 more

Open Access

https://doi.org/10.1371/journal.pone.0111218

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Journal: PloS one	Publication Date: Oct 30, 2014
Citations: 5	License type: CC BY 4.0

Affiliation: Guangzhou Center for Disease Control and Prevention

Abstract

Since Feb, 2013, more than 100 human beings had been infected with novel H7N9 avian influenza virus. As of May 2013, several H7N9 viruses had been found in retail live bird markets (LBMs) in Guangdong province of southern China where several human cases were confirmed later. However, the real avian influenza virus infection status especially H7N9 in Guangzhou remains unclear. Therefore, a cross-sectional study of avian influenza in commercial poultry farms, the wholesale LBM and retail LBMs in one district of Guangzhou was conducted from October to November, 2013. A total of 1505 cloacal and environmental samples from 52 commercial poultry farms, 1 wholesale LBM and 18 retail LBMs were collected and detected using real-time RT-PCR for type A, H7, H7N9 and H9 subtype avian influenza virus, respectively. Of all the flocks randomly sampled, 6 farms, 12 vendors of the wholesale LBM and 18 retail LBMs were type A avian influenza virus positive with 0, 3 and 11 positive for H9, respectively. The pooled prevalence and individual prevalence of type A avian influenza virus were 33.9% and 7.9% which for H9 subtype was 7.6% and 1.6%, respectively. None was H7 and H7N9 subtype virus positive. Different prevalence and prevalence ratio were found in different poultry species with partridges having the highest prevalence for both type A and H9 subtype avian influenza virus. Our results suggest that LBM may have a higher risk for sustaining and transmission of avian influenza virus than commercial poultry farms. The present study also indicates that different species may play different roles in the evolution and transmission of avian influenza virus. Therefore, risk-based surveillance and management measures should be conducted in future in this area.

Highlights

Human infection with H7N9 avian influenza virus was first reported in March in Eastern China [1]
H7N9 viruses had been isolated from poultry and environments at the live bird markets (LBMs) [7,8], the source of the infections remain unclear [9]
There are 238 commercial chicken farms, 663 commercial waterfowl farms, 30 commercial pigeon farms, 22 retail LBMs and one wholesale LBM with 15 vendors distributed in 13 towns of Huadu district

Summary

Introduction

Human infection with H7N9 avian influenza virus was first reported in March in Eastern China [1]. The infections caused global concerns about the potential of the virus to start an influenza pandemic [2,3] and have already caused huge economic losses for the poultry industry including trade in live poultry in China. While the highly pathogenic avian influenza A viruses (HPAIV), such as H5N1 and H7N7, often causes severe disease in poultry preceding human infections [4,5], the novel H7N9 virus causes no or only mild clinical signs in poultry [6]. This means that the H7N9 virus is likely to spread silently in poultry. H7N9 viruses had been isolated from poultry and environments at the LBM [7,8], the source of the infections remain unclear [9]

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