title: Analysis of signs and pathology of H5N1-infected ducks from the 2010-2011 Korean highly pathogenic avian influenza outbreak suggests the influence of age and management practices on severity of disease.
abstract: We compared the clinical signs, histopathological lesions and distribution of viral antigens among infected young (meat-type) and older (breeder) ducks that were naturally infected with the highly pathogenic avian influenza (HPAI) virus during the 2010-2011 Korean outbreak. The meat-type ducks had a high mortality rate (30%) and showed severe neurological signs such as head tremors and paresis. In contrast, HPAI-infected breeder ducks had minimal clinical signs but a decreased egg production rate. The histopathological characteristics of infected meat-type ducks included necrotic lesions of heart and brain, which may have primarily contributed to the high mortality rate. In contrast, the breeder ducks only presented necrotic splenitis, and viral antigens were only detected in the trachea, lungs and spleen. Younger ducks had a high viral titre in the organs, high levels of viral shedding and a high mortality rate after experimental HPAI virus infection. Compared to the breeder ducks, the meat-type ducks were raised in smaller farms that had poor quarantine and breeding facilities. It is therefore possible that better biosecurity in the breeder farms could have reduced the infection dose and subsequently the severity of the disease. Thus, age and management may be the influencing factors for HPAI susceptibility in ducks.
authors.affiliation: a Animal and Plant Quarantine Agency (QIA) , Anyang , Republic of Korea.
authors.forename: Moon-Young
authors.initials: MY
authors.lastname: Rhyoo
authors.forename: Kyung-Hyun
authors.initials: KH
authors.lastname: Lee
authors.forename: Oun-Kyung
authors.initials: OK
authors.lastname: Moon
authors.forename: Woo-Hee
authors.initials: WH
authors.lastname: Park
authors.forename: You-Chan
authors.initials: YC
authors.lastname: Bae
authors.forename: Ji-Youl
authors.initials: JY
authors.lastname: Jung
authors.forename: Soon-Seek
authors.initials: SS
authors.lastname: Yoon
authors.forename: Hye-Ryoung
authors.initials: HR
authors.lastname: Kim
authors.forename: Myoung-Heon
authors.initials: MH
authors.lastname: Lee
authors.forename: Eun-Joo
authors.initials: EJ
authors.lastname: Lee
authors.forename: Mi-Ran
authors.initials: MR
authors.lastname: Ki
authors.forename: Kyu-Shik
authors.initials: KS
authors.lastname: Jeong
mesh_terms: D000367:Age Factors; D000818:Animals; D000956:Antigens, Viral / Q000378:metabolism; D001921:Brain / Q000473:pathology; D004196:Disease Outbreaks / Q000662:veterinary*; D004372:Ducks; D006652:Histological Techniques; D007150:Immunohistochemistry; D053124:Influenza A Virus, H5N1 Subtype; D005585:Influenza in Birds / Q000453:epidemiology* / Q000473:pathology*; D009206:Myocardium / Q000473:pathology; D011201:Poultry Diseases / Q000453:epidemiology* / Q000473:pathology / Q000821:virology*; D056910:Republic of Korea / Q000453:epidemiology
chemical_list: D000956:Antigens, Viral