Identification of the source of A (H10N8) virus causing human infection.

A novel H10N8 influenza A virus has been detected in three humans in China since December 2013. Although this virus was hypothesized to be a novel reassortant among influenza viruses from wild birds and domestic poultry, its evolutionary path leading to human infection is unknown. Sporadic surveillance at the live poultry market (LPM) suspected to be the source of infection for the first H10N8 patient has shown a gradual increase in influenza virus prevalence culminating with a predominance of H10N8 viruses. Influenza viruses detected in the LPM up to 8 months prior to human infection contributed genetic components to the zoonotic virus. These H10N8 viruses have continued to evolve within this LPM subsequent to the human infection, and continuous assessments of these H10N8 viruses will be necessary. Serological surveillance showed that the virus appears to have been present throughout the LPM system in Nanchang, China. Reduction of the influenza virus burden in LPMs is essential in preventing future emergence of novel influenza viruses with zoonotic and pandemic potential.