Pathologic Changes in Wild Birds Infected with Highly Pathogenic Avian Influenza A(H5N8) Viruses, South Korea, 2014.

Hye-Ryoung Kim,Hyun-Kyoung Lee,Il Jang,Eun-Kyoung Lee,Yi-Seok Joo,Hee-Soo Lee,Kang-Hyun Baek,Yong-Kuk Kwon,Kyung-Hyun Lee,Hyun-Mi Kang,Youn-Jeong Lee,Byung-Min Song,You-Chan Bae

doi:10.3201/eid2105.141967

Abstract

In January 2014, an outbreak of infection with highly pathogenic avian influenza (HPAI) A(H5N8) virus began on a duck farm in South Korea and spread to other poultry farms nearby. During this outbreak, many sick or dead wild birds were found around habitats frequented by migratory birds. To determine the causes of death, we examined 771 wild bird carcasses and identified HPAI A(H5N8) virus in 167. Gross and histologic lesions were observed in pancreas, lung, brain, and kidney of Baikal teals, bean geese, and whooper swans but not mallard ducks. Such lesions are consistent with lethal HPAI A(H5N8) virus infection. However, some HPAI-positive birds had died of gunshot wounds, peritonitis, or agrochemical poisoning rather than virus infection. These findings suggest that susceptibility to HPAI A(H5N8) virus varies among species of migratory birds and that asymptomatic migratory birds could be carriers of this virus.

Highlights

In January 2014, an outbreak of infection with highly pathogenic avian influenza (HPAI) A(H5N8) virus began on a duck farm in South Korea and spread to other poultry farms nearby
We examined 8 Baikal teals, 3 bean geese, 1 whooper swan, and 2 mallard ducks naturally infected with HPAI A(H5N8) virus
The 2014 outbreak of HPAI A(H5N8) in South Korea was unexpected because the H5N8 subtype is uncommon in this area

Summary

Introduction

In January 2014, an outbreak of infection with highly pathogenic avian influenza (HPAI) A(H5N8) virus began on a duck farm in South Korea and spread to other poultry farms nearby. During this outbreak, many sick or dead wild birds were found around habitats frequented by migratory birds. Gross and histologic lesions were observed in pancreas, lung, brain, and kidney of Baikal teals, bean geese, and whooper swans but not mallard ducks Such lesions are consistent with lethal HPAI A(H5N8) virus infection. Since 2003, repeated outbreaks of HPAI virus subtype H5N1 infection have occurred in poultry flocks in several Southeast Asia countries, resulting in high mortality rates among domestic ducks and wild migratory birds [2]. We examined 8 Baikal teals, 3 bean geese, 1 whooper swan, and 2 mallard ducks naturally infected with HPAI A(H5N8) virus

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Conclusion