Among our rogues gallery of emerging HPAI H5 viruses in China, the H5N6 subtype holds particular interest because – like its venerable ancestor H5N1 – it has been shown to be capable of infecting, and killing, human hosts. While its track record isn’t long (it only first emerged in April of 2014), it has already been detected across large swaths of China and as far south as central Vietnam.
As is typical for avian flu, reports of outbreaks over the summer months tend to drop off, although they have not totally dried up.
Last April, and again in May, H5N6 was detected in wild birds in Hong Kong (see Hong Kong: Wild Bird Found Infected With H5N6), and over the summer Vietnam has reported several small poultry outbreaks. The biggest splash came in mid-July when China reported their 4th human infection, that of a 37 year-old woman in Yunnan Province.
Overnight the Chinese media is reporting an outbreak in Quingyuan City, Guangdong Province, along with an emergency order for agricultural interests to tighten up biosecurity and control efforts.
August 12 afternoon, then informed the Ministry of Agriculture and Veterinary Bureau of Qingyuan City, Fogang a farm suspected H5 subtype of avian influenza positive samples, the review confirmed as H5N6 bird flu.
After the outbreak, the provincial Agriculture Department attaches great importance to immediately send experts to the scene to guide emergency response work, and urgently allocated Qingyuan five tons disinfectants used for disinfection and original. Local authorities suspected outbreaks were blocked, and the outbreaks in poultry farms remaining 820 birds were culled and safe disposal, fully cleaned and disinfected. After the notification from the Ministry of Agriculture confirmed the outbreak, Fogang committee and government attach great importance to the blockade affected areas issued orders, but decided to affected areas (3 km radius of the infected range) within 13 poultry farms do culling all 38,110 birds treatment; poultry investigation by the county and found no abnormalities. Currently, the province has not received new reports of major animal epidemic.
August 13, the provincial Department of Agriculture issued an emergency notice requiring all localities to strengthen immunity, to ensure that "should be free to make free, do not stay neutral"; strengthening surveillance investigation, responsibility to the people, Fenpianbaogan; strengthen quarantine, slaughter and quarantine and circulation of supervision; guidance farms (households) to strengthen the integrated management of prevention, strengthen emergency preparedness personnel in place to ensure that when outbreaks of disease, specific responsibilities, contact the smooth, according to the law effective disposal in accordance with regulations.
This year, the province's agricultural sector at all levels strengthen immunization, surveillance and quarantine, as of now, the province's poultry 51,026,000 quarantine, slaughter and quarantine of poultry 41.632 million; 601 million copies of the actual immunization feather bird flu vaccine, should avoid immune population density of 100%; the province to monitor parts of HPAI sample 97485, the passing rate of 84.56 percent immunization, livestock effective immune protection status.
The impressive numbers cited in the final paragraph illustrate how much impact avian flu has had on Guangdong’s poultry industry this year, and shows the lengths to which they are going in order to keep HPAI viruses under control.
As the voracious consumer of nearly 91% of the world’s avian flu poultry vaccines ( cite Impact of vaccines and vaccination on global control of avian influenza by David Swayne), China has been able to reduce the visible impact of bird flu on their poultry industry, but not without some hidden costs.
It has been long known that poultry vaccines don’t always prevent disease – sometimes they just hide the symptoms. And that can allow HPAI viruses to propagate (and evolve) silently in vaccinated flocks.
In 2009 Professor C.A. Nidom, of the Institute of Tropical Disease, Airlangga University, Indonesia warned against relying on poultry vaccines to control bird flu (see Indonesia: Debate Over Poultry Vaccination), while that same year Zhong Nanshan, a respiratory disease specialist in China, warned that vaccinated poultry can still become infected (and possibly transmit) the H5N1 virus (see Chinese expert issues new bird flu warning).
Since then we’ve seen research (see here, here, and here) suggesting that poorly matched vaccines, often inconsistently or haphazardly applied, may be driving vaccine-escape flu variants, and may be at least partially responsible for the sudden emergence of new avian flu subtypes we’ve seen over the past couple of years (H5N3, H5N5, H5N6, H5N8, H7N9, H10N8, etc. ).
This sudden proliferation of HPAI H5 viruses in China prompted the FAO to issue an FAO-EMPRES Report On The Emergence And Threat Of H5N6 in early November of last year, which warned:
The possibility exists that wild birds could become infected and spread these viruses to other countries or continents. Migratory birds, which have played a key role in the introduction of H5N1 to Europe and Africa [Kilpatrick et al, 2006] and of H5N8 to the Republic of Korea [Jeong et al, 2014], could spread the viruses to other countries or continents.
As if on cue, H5N8 showed up – first in Europe, and then in North America - at practically the same time this report was released. The obvious concern is that other subtypes might eventually follow H5N8’s lead, and make their way out of China and Southeast Asia.
While the damage wrought by H5N8 to poultry interests in Europe and North America has been considerable, so far it hasn’t posed any serious human health hazards.
Things would become far more complicated if H5N1, H7N9, or H5N6 – all capable of infecting humans hosts - should ever follow in H5N8’s globetrotting footsteps. So we follow outbreaks like the one in Guangdong province with considerable interest.