Less than a year after the emergence of a novel bird flu virus A H7N9 in China, yet another new avian virus strain — A H10N8 (JX346) — has emerged in China and been found responsible for the death of a 73-year-old woman.
According to a report published on Wednesday in The Lancet, the woman who was admitted to a hospital with a fever on November 30 last year died in nine days after the onset of illness. The cause of death has been attributed to severe pneumonia and multiple organ failure. The woman was suffering from chronic medical conditions.
The source of infection has not been firmly established, though the woman visited a live poultry market, but did not handle the chicken, a few days before the onset of illness. No evidence of human-to-human transmission has been found.
Whole genome sequencing of samples obtained from the trachea established that H10N8 is a novel reassortant virus. All the genes were of avian origin with six genes coming from the A H9N2 viruses.
The H10N8 avian virus has originated from multiple reassortments of H10 and N8 avian virus subtypes. HaiYing Chen from Nanchang City Disease Control and Prevention, Nanchang and the first author of the paper and others postulate that the reassorted H10N8 virus first appeared in wild birds and then moved over to poultry. The second reassortment of H10N8 with H9N2 took place in poultry. In the “absence of surveillance data”, it is not possible to conclusively state the precise origin and evolution process and reassortment processes, they stated.
Phylogenetic analysis revealed that “the haemagglutinin gene of JX346 belonged to the Eurasian avian lineage and the neuraminidase gene belonged to a subcade of North American avian lineage,” they write.
According to the authors, avian influenza H10 and N8 subtype viruses have been “widely” circulating in birds in China. While human infection with H10 subtype has been previously found in Egypt in 2004 and Australia in 2010, no human infection with N8 subtype has been ever reported.
H10N8 viruses have been found in China in 2007 from a water sample taken from Dongting Lake in Hunan province and from a live poultry market in Guangdong province in 2012.