Genetic Diversity of Avian Influenza A (H10N8) Virus in Live Poultry Markets and Its Association with Human Infections in China

Abstract

Following the first human infection with the influenza A (H10N8) virus in Nanchang, China in December 2013, we identified two additional patients on January 19 and February 9, 2014. The epidemiologic, clinical, and virological data from the patients and the environmental specimen collected from 23 local live poultry markets (LPMs) were analyzed. The three H10N8 cases had a history of poultry exposure and presented with high fever (>38°C), rapidly progressive pneumonia and lymphopenia. Substantial high levels of cytokines and chemokines were observed. The sequences from an isolate (A/Environment/Jiangxi/03489/2013 [H10N8]) in an epidemiologically linked LPM showed highly identity with human H10N8 virus, evidencing LPM as the source of human infection. The HA and NA of human and environmental H10N8 isolates showed high identity (99.1–99.9%) while six genotypes with internal genes derived from H9N2, H7N3 and H7N9 subtype viruses were detected in environmental H10N8 isolates. The genotype of the virus causing human infection, Jiangxi/346, possessed a whole internal gene set of the A/Environment/Jiangxi/10618/2014(H9N2)-like virus. Thus, our findings support the notion that LPMs can act as both a gene pool for the generation of novel reassortants and a source for human infection, and intensive surveillance and management should therefore be conducted.

Epidemiology, Evolution, and Recent Outbreaks of Avian Influenza Virus in China

“…The recently emerged reassortant AIVs, such as the H7N9, H10N8, and H5N2 subtypes found in domestic poultry, appear to be related to the widespread H9N2 viruses (6,10,12). To our knowledge, AIVs originating from wild birds are not always adapted to infect domestic birds (12).…”

“…Therefore, poultry show few symptoms of infection with H7N9 and H10N8, but these viruses retain the ability to cause severe disease in humans. A high prevalence of H9 and H5 AIVs can be found in poultry species regardless of location, but H7 and H10 viruses are rarely detected on poultry farms and seem to be amplified mainly among birds in live-poultry markets (LPMs) (6,7). Novel H5N1, H5N2, H5N6, and H5N8 HPAIVs strains have been found in China since 2000, and the overall prevalence of H5 viruses appears to be increasing since 2010.…”

“…The practice of backyard farming is gradually disappearing and being replaced by regular poultry farms, in which chickens are raised in closed henhouses. However, a slowdown in the emergence of novel AIV reassortants in China has not yet been observed, as evidenced by the presence of novel H7N9, H10N8, and H5N6 AIVs in LPMs and H5N6 in poultry farms (6,9,13). LAMs or LPMs are able to provide ample opportunities for wild aquatic birds, domestic poultry, mammals, and humans to closely interact and potentially share influenza pathogens, resulting in the emergence of novel viruses ( Fig.…”

“…H7N9 AIVs are able to bind human receptors, and the S138A, G186V, T221P, and Q226L mutations in the HA antigen have been shown to enhance this interaction (19). H10N8 viruses preferentially bind to avian receptors (21); however, documented human infections with H10N8 virus suggests that the virus may also be able to bind human receptors (6). The increasingly numerous H9N2 AIVs with the Q226L mutation in HA also appear to be able to bind to human-type receptors (15).…”

High Pathogenicity of Influenza A (H10N8) Virus in Mice

“…The recent study revealed that cytokines were strongly induced in H10N8 infection cases, especially in the fatal cases. 17 And this study also showed the human isolate of H10N8 virus provoked acute and persisting cytokine expression in mice, indicating this virus can cause a cytokine storm in mammals.…”