Vietnam Reports 2 Outbreaks Of H5N6 In Poultry

Bà Rịa-Vũng Tàu - Credit Wikipedia

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One of the happy by-products of China's massive poultry vaccination campaign - which began in the summer of 2017 - has been the dampening of HPAI avian flu reports (in humans, and in poultry) all across Asia.

And while avian flu activity has been greatly suppressed for nearly 2 years, we've seen a few cracks in the veneer over the past 12 months. 

• In early April we saw the China's first H7N9 human infection (Gansu Province, Ex Inner Mongolia) in more than a year, and a month ago, Liaoning Province reported an H7N9 outbreak in poultry. 
• In 2018 China reported 5 human H5N6 infections - 4 of which occurred last fall - and a smattering of H5N6 outbreaks in poultry.
• In April China reported their first outbreak of HPAI H5N1 (in poultry) since the summer of 2018. 
• In February of 2018 Jiangsu China Reported the 1st Novel H7N4 Human Infection, a subtype that has also been identified in Cambodia. 
• And in the 24 months since China's H5+H7 poultry vaccination campaign, there have been 11 human H9N2 cases reported (see FluTrackers List).

 Vietnam, which has seen sporadic outbreaks of HPAI H5N6 in poultry since the virus first emerged in 2014, has reported two previous H5N6 outbreaks in 2019 (OIE report #1, OIE Report #2).

The latest, reported today by Viet Nam News.

Influenza A (H5N6) outbreak in Bà Rịa-Vũng Tàu

Update: August, 06/2019 - 16:25

BÀ RỊA-VŨNG TÀU — Two new outbreaks of the A/H5N6 avian influenza, which is transmittable to humans, has been reported in Xuyên Mộc District, the southern province of Bà Rịa-Vũng Tàu, said head of the provincial animal health agency, Nguyễn Lương Trai. 

The two outbreaks have reportedly occurred in farms of two households in Phước Thuận Commune.

After testing samples from the dead fowls, the agency found that they contained the A/H5N6 virus. Local authorities later destroyed 10,500 infected chickens.

The agency requested local authorities to spray chemicals to decontaminate farms.

The provincial agriculture sector asked the provincial People's Committee to devise plans and mobilise forces to prevent the disease, spray chemicals in high-risk areas and keep a close watch on the growth of their poultry populations.
The health sector was required to closely monitor human influenza, preventing diseases spreading to humans.

Earlier in April, a new outbreak of A/H5N6 was also reported in northern Lạng Sơn Province. — VNS

Unlike China, which has reported at least 23 human infections with H5N6, Vietnam has yet to record a human case despite a significant number of outbreaks. 

As we've discussed previously, influenza subtypes can encompass a wide array of similar - yet behaviorally different - viruses. 

Three years ago we knew of at least 34 genotypes of H5N6 (see Cell Host Microbe: Genesis, Evolution and Prevalence of HPAI H5N6 In China), but only 4 of them had been implicated in human infection.

While two years ago, in Nature Sci Rpts: H5N6 Viruses Exhibit Varying Pathogenicity & Transmissibility In Mammals, we looked at a Journal Nature (open access) report that compared three genetically similar, but behaviorally different, H5N6 viruses collected in Hubei Province, China.
 
The viruses continue to evolve, and their pathogenicity can wax and wane over time.  So while H5N6 haven't sparked human infections in Vietnam up until now, there are no guarantees going forward.