The H7N9 strain of bird flu appeared in China in February, claiming its first casualties in March. So far, there have been 130 recorded infections and 37 deaths. While anxiety over the spread of the virus is easing after recent evidence has shown its dissipation, scientists are cautioning against complacency, as H7N9 could reemerge after the summer months. From Reuters:
A new and deadly strain of bird flu that emerged in China in February but seems to have petered out in recent months could reappear later this year when the warm season comes to an end – and could spread internationally, scientists said on Monday.
[…]”The warm season has now begun in China, and only one new laboratory-confirmed case of H7N9 in human beings has been identified since May 8, 2013,” the researchers wrote in a study published in The Lancet medical journal.
But they added: “If H7N9 follows a similar pattern to H5N1, the epidemic could reappear in the autumn.”
[…]The team urged health officials and doctors not to be lulled into a false sense of security by the sharp drop off in H7N9 cases in recent weeks.
“Continued vigilance and sustained intensive control efforts against the virus are need to minimize risk of human infection, which is greater than previously recognized,” they said. [Source]
The research cited in recent media reports on H7N9 comes from two studies published in The Lancet medical journal: “Comparative Epidemiology of Human Infections With Avian Influenza A H7N9 and H5N1 Viruses in China,” and “Human Infection With Avian Influenza A H7N9 Virus: An Assessment of Clinical Severity.” The former study looks at data on the H5N1 bird flu that spread internationally after emerging in China in 2003 to determine that the new strain is less severe in terms of fatality. While some headlines are stressing this finding, the South China Morning post looks to data in the study regarding the H1N1 “swine flu” pandemic of 2003 to reiterate a cautionary message:
The rate of fatality in hospitalised H7N9 patients was 36 per cent, compared to 5 per cent to 20 per cent in swine flu patients and 65 per cent in H5N1 patients in China.
“One-third hospital fatality is not a small figure. Killing of chickens and market closures may still be needed when the epidemic reappears. I believe these measures should not be relaxed,” said Professor Gabriel Leung, director of the university’s Public Health Research Centre who announced the findings on Monday.
They warned watchdogs not to take comfort from a lull in new infections, as the virus may reappear in the autumn. [Source]
Also see prior CDT coverage of the H7N9 avian influenza virus.