Influenza A(H10N3) virus in Humans

Influenza A(H10N3) virus is not truly new and has been circulating in domestic ducks in Southeast-Asia for a while[1,2]. No news there, but the interest bit of new news was that this virus has jumped a species barrier and now has been shown to be able to infect humans too.

On April 28, 2021 a male patient from the city of Zhenjiang located in northeastern China was hospitalised with fever and other influenza-like symptoms. A few days later, the patient was in a stable condition and could be discharged form hospital. All close contacts were under medical observation.

The Chinese Center for Disease Control and Prevention conducted a whole genome sequence determination of the patient specimens. The result was positive for the Influenza A(H10N3) virus.

Scientists think that – at the moment – Influenza A(H10N3) has a low pathogenicity, which means it causes relatively less severe disease in poultry and is unlikely to cause a large-scale outbreak. They hope. No other cases of human infection with Influenza A(H10N3) have ever been reported globally.

Only around 160 isolates of the virus were reported in the 40 years to 2018, mostly in wild birds or waterfowl in Asia and some limited parts of North America, and none had been detected in chickens so far.

Analysing the genetic data of the virus will be necessary to determine whether it resembles older viruses or if it is a novel mix of different viruses.

[1] Wisedchanwet et al: Influenza A virus surveillance in live-bird markets: first report of influenza A virus subtype H4N6, H4N9, and H10N3 in Thailand in Avian Diseases – 2011
[2] Zhang et al: Characterization of the Pathogenesis of H10N3, H10N7, and H10N8 Subtype Avian Influenza Viruses Circulating in Ducks in Science Reports – 2017