People are seen in this file photo from April 14, 2013 wearing facemasks after an outbreak of bird flu.Mark Ralston/AFP/Getty Images
The death of a woman in China from a strain of bird flu previously unknown in humans is a reminder of the ever-present threat of mutating animal viruses, scientists said Wednesday, while cautioning that it may be too early to tell if it has the potential to become a pandemic.
The latest strain, H10N8, killed a 73-year-old Chinese woman in December, and Chinese authorities last week confirmed a second human case of the strain in another woman who remains critically ill in a hospital.
"There are several genetic markers which may indicate a predisposition to humans," Marc-Alain Widdowson, a researcher at the Centers for Disease Control and Prevention said of the H10N8 strain. Speaking to Al Jazeera on Wednesday, Widdowson also cautioned that it was "too early to tell" if it constituted a serious threat.
Still, warned Jeremy Farrar, a flu expert and director of health charity Wellcome Trust, "We should be especially worried when those viruses show characteristics that suggest they have the capacity to replicate easily or to be virulent or resistant to drugs."
"This virus ticks several of these boxes and therefore is a cause for concern," Farrar told Reuters.
Meanwhile, there have been 298 cases to date in China of another new strain of bird flu, H7N9, Gregory Hartl, a spokesman for the World Health Organization (WHO), confirmed to Al Jazeera. Of those cases, about 60 people have died.
Chinese scientists who conducted a genetic analysis on samples of the H10N8 virus taken from the woman who died said it was a new genetic reassortment of other strains of bird flu viruses, including one called H9N2, which is regularly found in poultry in China. They published their findings in The Lancet medical journal.
According to the scientists' study of her case, the 73-year-old victim from Nanchang City in eastern China was admitted to the hospital with a fever and severe pneumonia on Nov. 30, 2013. Despite being treated with antibiotic and antivirals, her health deteriorated rapidly, and she sustained multiple organ failure, dying nine days after her symptoms first emerged. The source of her contamination remains unknown.
Dr. Ben Cowling, division head and associate professor at the School of Public Health at the University of Hong Kong, told Al Jazeera that Chinese officials have been very open about their investigation and are putting "a lot of effort into controlling the strain in humans."
Authorities in eastern China announced a ban last Tuesday on live poultry sales following a spike in the number of people infected with the H7N9 strain of bird flu during the busy Chinese New Year travel period, while Hong Kong began culling 20,000 chickens.
Other flu experts not directly involved in the study of H10N8 agreed it was an important reminder of the potential threat from circulating and mutating flu viruses, but said it did not appear to be a particular concern at the moment.
Ben Neuman, a virologist at Britain's University of Reading said while the fatal H10N8 case was a "personal tragedy for the family and friends of the victim" and needed to be watched closely, "there is no cause for alarm at this time."
Al Jazeera and wire services