Credit UK Defra
Between 2004 and 2007 the H5N1 avian flu virus expanded its range, going from basically being a problem for a handful of Southeast Asian countries, to being a problem for much of Europe, Asia, and the Middle East. We saw huge wild bird die offs in China, Indonesia, and Eastern Europe, along with thousands of poultry infestations and culling operations.
Along the way, several hundred humans were infected as well.
In 2008, H5N1’s expansion seemed to halt, and in many places the virus actually receded, leaving behind about a dozen places around the world where the virus remained entrenched. Among them were Indonesia, Vietnam, Egypt, Cambodia, India, Pakistan, Bangladesh, and China.
Even in these countries, the number of outbreaks reported – and the number of human infections – dropped markedly, with the peak reached in 2006 (n=115) and steadily dropping since then (2013= 39 cases). The foci of infections also shifted away from Vietnam and Indonesia towards Egypt and Cambodia.
While never quite going away, it seemed as if the avian flu threat was simply fading away.
That is, until a new avian flu virus – H7N9 – appeared abruptly in China in the spring of 2013 sparking two consecutive winter epidemics, and is expected to return again this winter as well. In quick succession, several more avian flu viruses appeared – including H5N8 in Korea (now spread to Europe & Japan), H5N6 in China and Vietnam, H5N3 in China, and H10N8 in China.
Now, instead of one avian flu threat, we have anywhere from three to six to keep track of (H5N1, H7N9, H5N8, H5N6, H5N3, H10N8), and no one should be terribly surprised if several more novel reassortants emerge over the next couple of years.
Reassortant viruses emerge when two different flu viruses share a common host and swap genetic components. Most reassortant viruses are evolutionary failures, but every once in awhile a more `fit’ virus emerges.
Not only are there more `building blocks’ in play, for flu viruses to swap and play with, the poultry vaccines in use in China and elsewhere are losing their effectiveness, and that may be promoting the creation of new flu strains (see EID Journal: Subclinical HPAI In Vaccinated Poultry – China).
In recent weeks we’ve seen more bird flu stories, from more diverse locations, than we have in a number of years. While this may be a flash in the pan, for now bird flu concerns are once more on the ascendant – albeit, for now, mostly for poultry operations.
With so much going on in India, Korea, Japan, the Netherlands, Germany, the UK, and Egypt – instead of blogging separately about these news stories – I’ve put together a morning round up.
Our first stop: India, where over the past few days we’ve seen reports of massive duck die offs in Kerala, and government plans to cull 200,000 birds. While initially only identified as an HPAI H5 virus, today multiple media sources are reporting the virus is the H5N1 subtype.
Updated: November 27, 2014 15:56 IST
Kottayam: Kerala has confirmed that the outbreak of bird flu in the state is of the feared H5N1 strain, which is highly contagious and can be fatal to humans.
Government officials said that massive culling of birds is being done to prevent the spread of the disease.
The virus itself killed about 15,000 infected ducks in Kottayam and another 500 in nearby Alappuzha, the first cases of the disease in the country since February this year.
Meanwhile, in Korea, there are fresh reports the the H5N8 virus – which emerged there last January and proceeded to devastate the poultry industry - has been detected again on a poultry farm in the coastal city of Gyeongju in Gyeongsang Province.
Pyongyang, November 26 (KCNA) -- A bird flu occurred at a chicken farm in Kyongju City, North Kyongsang Province, south Korea on Nov. 24, according to KBS of south Korea.
Hundreds of chickens were culled and buried.
It was also reported that bird flu caused by migratory birds is spreading.
In Japan, another report of migratory bird feces testing positive for the H5N8 virus, this time in Tottori.
November 27, 2014
Ministry of the Environment is the 27th, highly pathogenic avian influenza virus from droppings of ducks found in Tottori (H5N8 subtype) was detected, was announced. Domestic wild birds in the highly pathogenic avian influenza has been confirmed Shimane Prefecture Yasugi, season three cases eyes continued to Chiba Prefecture Nagara.
And from Taiwan this morning, reports (h/t Ronan Kelly of FluTrackers) of both H7N9 and H7N5 in migratory bird feces samples collected this month from Tainan City, in the southwest of Taiwan. Further testing will be required to determine the pathogenicity of these subtypes.
Published date: 2014/11/27 morning 10:55:20| last modification date: 2014/11/27 10:55:20
Four wetland today in this city (103) on November 15, feces sampling inspection in routine monitoring of migratory birds on 25th H7N5 and subtype H7N9 avian influenza viruses isolated, identified highly pathogenic virus does not at present, but homologous strains is a city, pending final confirmation.
Protection of animal epidemic prevention Department said in this city, as a safeguard against four grass migratory birds carrying the virus, around the 25th started 6 games within a 3 km radius of poultry farms quarantine measures, including 1 feeding chickens, health situation is good, same day sampling inspection. Animal Health Department has stepped up poultry farms in and around the public road disinfection and epidemic prevention work, and to strengthen the poultry farm visits and monitoring of the epidemic, and take precautions against the epidemic. According to the sampling frequency of the disposal process 1 times per month on poultry farms within 3 kilometers to strengthen monitoring for 3 months after confirming that the avian influenza virus activity was not detected, you can unlock the wetlands regional monitoring measures.
Meanwhile we continue to see scattered media reports of bird flu `alarm’ in Egypt, amid numerous poultry outbreaks and three recent human infections (see Meanwhile, Back In Egypt . . . .), and Europe continues to ratchet up their biosecurity measures against any further introductions of the H5N8 virus (see Defra updated bird flu guidance).
While the public health threat fairly remains low from these viruses, the one constant with influenza viruses is their capacity for change. So we watch these outbreaks carefully, for any signs that these viruses may be evolving into a greater human health threat.