|Yunnan Province - Credit Wikipedia|
Between 1998 and 2014, the World Health Organization reported only 18 human H9N2 cases worldwide. In 2015, that number jumped by 9, and so far in 2016, we've seen 5 more (see FluTracker's List).
Whether this sudden increase is due to better testing and reporting (a distinct possibility), or due to a change in the virus (also possible), is unknown.
Whatever the cause, for the second time in a week (see last week's Guangdong Province Reports A Human Infection With H9N2), China is reporting a new H9N2 infection.
Release Date: 2016-08-26Yunnan Provincial Health and Family Planning Commission August 26 briefing: Yunnan Provincial Health and Family Planning Commission after entering the flu and other respiratory diseases in spring and summer high season, stepped up surveillance of influenza, such as pneumonia of unknown causes.
In monitoring, from one case of influenza-like illness were detected H9N2 avian influenza virus nucleic acid positive. August 25, Chinese Center for Disease Control and Prevention for further review of test results for influenza A H9N2 avian influenza virus nucleic acid positive. Expert consultation, clinical manifestations of cases, the results of laboratory tests and epidemiological history, diagnosis in this case as H9N2 cases. Children, male, 10 months old, now living in Mengzi City. Currently children have been cured, all close contacts without exception.
Experts believe judgments, of H9N2 virus is a subtype of influenza A virus, the source of the virus is poultry in bird flu more common for people is a low pathogenic virus. The case report of sporadic cases, the risk of transmission is very low, the situation does not appear human to human transmission.
H9N2 infections in humans - while still rarely reported - are almost certainly more common than we know, primarily because surveillance in humans is very limited in the regions where it circulates.
A 2014 seroprevalence study, however, found antibodies against H9N2 ranged from 5.9% to 7.5% among poultry exposed individuals in Egypt.
On the positive side, H9N2 infection in humans has generally been mild, and no human-to-human spread has been detected. H9N2 does reassort readily with other viruses, and has been picking up mammalian adaptations in recent years.
While the H9N2 virus may have some limited pandemic potential on its own accord, the bigger danger is that it could acquire more `mammalian' adaptations, and then share those (via reassortment) with other, more pathogenic, viruses.