China alerted WHO 24 days after the woman was hospitalised & 11 days after her death, against the mandated 24 hours
Photo: iStock China recorded the first human death caused by H3N8, a strain of the avian influenza virus, in the third human case ever recorded globally. The other two human cases were also reported from China in April-May 2022.
The patient, a 56-year-old woman from Guangdong province, fell ill on February 22, 2023, was hospitalised with severe pneumonia on March 3 and died on March 16. The World Health Organization (WHO) was notified of this incident on March 27.
The National Health Commission of the People’s Republic of China alerted the global health body 24 days after the woman was hospitalised and 11 days after her death, against the mandated 24 hours within which countries must report human cases of non-human flu infections under the International Health Regulations.
In its disease outbreak update from April 11, the WHO noted “it is still unclear what the exact source of this infection is and how this virus is related to other avian influenza A(H3N8) viruses that are circulating in animals”.
No other contacts of this case, or the other two from earlier last year, tested positive for the virus, indicating that the virus does not spread easily among humans. So, national and international level risk remains low.
“However, due to the constantly evolving nature of influenza viruses, WHO stresses the importance of global surveillance to detect virological, epidemiological and clinical changes associated with circulating influenza viruses which may affect human (or animal) health,” the United Nations health agency noted.
Of the previous two cases, one patient was critical and the other had a mild illness. Both have since recovered.
The latest fatal case was detected through the severe acute respiratory infection (SARI) surveillance system and had a history of live poultry exposure and interaction with live birds around her home before she fell ill.
“Environmental samples were collected from the patient's residence and the wet market where the patient spent time before the onset of illness. The results of testing showed that the samples collected from the wet market were positive for influenza A(H3),” said WHO.
This strain of avian influenza has commonly been detected in birds from across the world, with even cross-species transmission to some mammals. However, it doesn't jump into humans easily, occurring sporadically and in very specific contexts.
Most human infections with avian influenza viruses that have been reported previously were due to exposure to infected poultry or contaminated environments, the WHO noted. “Since avian influenza viruses continue to be detected in poultry populations, further sporadic human cases are expected in the future.”
Another strain of avian influenza, H5N1, made headlines just last month when an 11-year-old girl died of the infection in Cambodia. Not long before that, the virus was also routinely being found in many mammals including minks, bears, foxes, skunks, possums, racoons and seals.
For now, human to human transmission of H5N1 also remains low, much like H3N8. Having said that, more than 800 human cases of this strain have been recorded since the first outbreak in 1997 in Hong Kong. Half of these cases were fatal.
However, while the pandemic threat from H5N1 is high, it has not particularly increased over the past 25 years. “It is very difficult to assign a quantitative risk to these viruses. We have some idea of what changes this virus has to make to become more human-adapted, but we don’t have a good feel for how easily the viruses can make these changes,” Richard Webby, director of the World Health Organization Collaborating Centre for Studies on the Ecology of Influenza in Animals and Birds, had earlier told Down To Earth.
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