Variability in Pathobiology of South Korean H5N1 High-Pathogenicity Avian Influenza Virus Infection for 5 Species of Migratory Waterfowl

Abstract

The pathobiology of H5N1 high-pathogenicity avian influenza (HPAI) virus infection in wild waterfowl is poorly understood. This study examined the pathobiology of A/chicken/Korea/IS/06 (H5N1) HPAI in 5 migratory waterfowl species-mute swans (Cygnus olor), greylag geese (Anser anser), ruddy shelducks (Tadorna ferruginea), mandarin ducks (Aix galericulata), and mallard ducks (Anas platyrhynchos)-following intranasal inoculation or contact exposure, from which all birds became infected. In mute swans, this virus had strong vascular endothelial cell tropism, producing acute severe disease and 100% mortality; the virus was detected in various parenchymal cells; and necrotic and inflammatory changes were noted in a range of organs, including pancreas, brain, spleen, heart, oral cavity, adrenal gland, lung, and liver. The ruddy shelducks had 100% mortality, but time to death was delayed, and the lesions were primarily restricted to the brain, heart, pancreas, and spleen. The mandarin ducks had only a single mortality, with lesions similar to those in ruddy shelducks. The greylag geese became infected, developed neurological signs, and had residual meningoencephalitis when examined at termination but lacked mortality. The mallards had asymptomatic infection. These results indicate variation in the pathobiology of H5N1 virus infections in different species of wild waterfowl, ranging from severe, acute systemic disease with 100% mortality to asymptomatic infection of respiratory and gastrointestinal systems.

Pathogenicity of an H5N1 Highly Pathogenic Avian Influenza Virus Isolated in the 2010–2011 Winter in Japan to Mandarin Ducks

“…2). A similar result was reported in mandarin ducks infected with a virus in clade 2.2 [8]. The virus titers in laryngopharyngeal swab samples were up to 10 3.5 TCID 50 /ml, suggesting that the transmission of the virus among mandarin duck flocks is unlikely to occur.…”

“…In this study, the birds did not show any neurological symptoms, and no virus was isolated from the brains. It was previously reported that histological lesions and viral antigen were observed in the brain of a mandarin duck that died of H5N1 HPAIV infection [8]. This discrepancy may be because the strains used in this study and the previous study had different tissue tropisms.…”

“…Kwon et al reported the pathobiology of A/chicken/Korea/IS/2006 (H5N1), whose hemagglutinin (HA) gene was classified into clade 2.2, in mandarin ducks [8]. However, pathogenicity of the current circulating H5N1 HPAIVs belonged to Clade 2.3.2.1 worldwide is still unknown.…”

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

“…However, there were different views for HPAI pathogenesis in ducks because lesions of vascular damage were rarely observed in previous HPAI experimental infection studies in ducks (Kuiken et al, 2010;Pantin-Jackwood et al, 2012). Multiple virus-associated necrotic lesions in one or more organs (pancreas, heart, brain) were responsible for death, and tissue tropism has also been observed in avian species such as mute swans, ruddy shelducks and mandarin ducks (Kwon et al, 2010). The data from this study also showed negligible vascular damage lesions and absence of viral antigens in the vascular endothelial cells in 220 ducks.…”

Oncolytic Activity of Avian Influenza Virus in Human Pancreatic Ductal Adenocarcinoma Cell Lines

“…Several observational studies have indicated the predilection of both HP IAVs and IAVs with low pathogenicity (LP) for the pancreas in domesticated avian species and migratory waterfowl following experimental or natural infection (20)(21)(22)(23)(24)(25)(26)(27)(28)(29). Necrosis of the pancreatic ductal epithelium was observed in ferrets intragastrically infected with HP H5N1 virus (30), and pancreatic postmortem lesions ranging from inflammation to necrosis have also been observed in HP-IAV-infected cats (31,32).…”