Japan is currently experiencing its worst ever highly pathogenic avian influenza (HPAI) outbreak wave.
According to the agriculture ministry, the number of confirmed outbreaks so far for the 2022-2023 season stood at 54, reported Kyodo News on January 3. In poultry, cases have occurred in 24 prefectures since the first infection was confirmed in the last week of October. Around 7.75 million birds have been culled in Japan so far as a result of the H5N1 virus serotype.
Previously, the country recorded its highest losses in 2020-21. Between November and March, there were 52 confirmed outbreaks in 18 prefectures. Around 9.9 million poultry were culled over that period.
Latest official notification to the World Organisation for Animal Health (WOAH) puts Japan’s total outbreaks in commercial birds at 48 (to December 25). Directly impacted at that time were more than 7.15 million poultry.
Involving almost 3.65 million birds, the two most recent WOAH reports cover 26 confirmed outbreaks starting in the period December 1-25. Of these, 21 were in laying flocks, each with between 28,000 and 1.4 million birds. Also affected were three premises with broiler chickens, and two with ducks. Among the latest outbreaks were the first this season in eight prefectures.
In more recent updates, Japan’s agriculture ministry has confirmed a further six outbreaks on farms linked to the H5N1 HPAI virus (as of January 5). Of these, five were in laying hens in flocks of between 10,000 and 290,000 birds, and the virus was also detected in around 400 ostriches and emus. Gunma is the latest prefecture to report its first cases this season.
In recent days, agreement has been reached for exports of poultry products to resume from two prefectures to Hong Kong and Singapore, according to the ministry. This follows agreement with the authorities of these destinations to accept the concept of regionalization for the purposes of trade. Currently included in the agreement are products from the prefectures of Hokkaido and Hyogo. Furthermore, the ministry reports, similar discussions are ongoing with other possible future destinations.
South Korea’s outbreak total reaches 59
Over the past few days, authorities in South Korea have registered with WOAH a further 52 HPAI outbreaks in commercial poultry. Affected were around 2.83 million birds in 10 provinces/city regions over the period November 3 to December 26.
Flock size impacted ranged from 124 birds up to 400,000, including seven flocks of more than 100,000 poultry. Type of bird is not specified in these reports.
Since the H5N1 HPAI virus was first detected in the country in November of 2021, South Korea has notified WOAH of 102 outbreaks involving more than 7.87 million poultry.
In the latest outbreak wave, the national authority reports the detection of an HPAI virus belonging to the clade 2.3.4.4b, comprising a genetic reassortment of Eurasian and North American origin.
Latest updates from the agriculture ministry put the number of outbreaks in South Korea since October of 2022 at 59 (as of January 3). Affected have been 23 farms with meat ducks, 20 with laying hens, 10 broiler flocks, and three with breeding poultry. Also testing positive for the virus have been one premises each with quail, native chickens, and ornamental birds.
As in Japan, the current HPAI wave in South Korea is hitting the egg sector particularly hard. In order to stabilize prices, the agriculture ministry announced a pilot scheme in December to import eggs.
With the outbreaks showing little sign of abating, the national disinfection period has been extended by the ministry for a further month. Until January 20, extra controls and disinfection are being focused on area with a high density of laying hens, especially those near rivers that attract wild birds, and flocks comprising 200,000 or more hens.
Other measures being applied are one day each week when traditional markets will be closed for thorough cleaning and disinfection. The ministry has delegated any decision to impose a ban on free-range poultry keeping to local authorities.
Asia accounts for almost two-thirds of global egg production, according to a review of the continent’s top egg companies in the latest edition of Poultry International.
Further outbreaks in Israeli poultry flocks
Over the past two weeks, Israel’s veterinary agency has registered with WOAH six more outbreaks of HPAI in commercial birds.
Affected were three flocks each of broiler chickens and meat turkeys — a total of 265,500 birds. Three of the latest outbreaks were in the Central District, and there were also the first cases in the current outbreak wave in the Southern District, and in Haifa.
Since mid-November, presence of the H5N1 virus has been confirmed in nine commercial poultry flocks in Israel. Directly impacted have been 303,500 birds, 1,350 of which died.
Taiwan registers four new HPAI outbreaks
According to the latest WOAH notification, the H5N1 HPAI virus has been detected at three more poultry farms in different counties of Taiwan.
Between late November and early December, two flocks of meat ducks and another of unspecified poultry type — a total of almost 43,000 birds — were directly impacted by this virus. They bring the outbreak total since mid-November of 2022 to four.
Also testing positive for HPAI in early December were laying hens at another farm. The presence of the H5N2 virus serotype was confirmed after more than 15,800 of the 24,425 hens at the premises died at the start of December.
This latest outbreak brings Taiwan’s total linked to the H5N2 variant since November of 2021 to 43.
Indian firm set to manufacture avian flu vaccine
In move to improve avian flu control in future, Indian animal health company Hester Biosciences is to manufacture a low-pathogenic avian influenza (LPAI) H9N2 strain inactivated vaccine for poultry.
The deal was effected by government body Agrinnovate India with the Indian Council of Agricultural Research (ICAR), reported Money Control. The firm plans to launch the vaccine at the end of this year, following successful field testing and regulatory approval.
Conferring effective immunity for chickens for around six months, the vaccine will be manufactured in India and initially sold there. Sales may be extended later to other Asian and African states through the firm’s own distribution channels.
According to the report, the H9N2 LPAI virus results in low mortality in poultry. However, it is associated with other pathogens that result in significant economic losses, such as reductions in egg production and broiler performance.
HPAI situation elsewhere in Asia
Two weeks ago, India Today reported that more than 6,000 poultry had been culled in Kerala to control the spread of HPAI. Involving mainly ducks, the cull took place in three communities in the Kottayam district of this southern state.
In Hong Kong, a wild bird found dead at a wetland park in early December tested positive for the H5N1 HPAI virus. Three weeks later, the territory’s authority declared to WOAH that the disease situation was “resolved.” No further cases were detected following increased surveillance, which had also covered two nearby poultry farms.
HPAI has been brought under control in the Magadan region of Russia’s Far Eastern federal district. According to WOAH notifications, all 72 poultry in a backyard flock died during October and November, but no cases have been detected in the area since that time.
Further cases of HPAI in wild birds have been reported to WOAH by the veterinary agency of Japan. Many more cranes have died from the disease in a “hot-spot” for the H5N1 virus in Izumi city on the southwestern island of Kyushu. New cases have also been discovered elsewhere in the country.
Furthermore, the agency has notified WOAH about the detection of a different HPAI virus in a wild bird. In October, a buzzard found dead in central Honshu tested positive for an H5 virus of a different but as yet unreported subgroup.
Following a nine-month hiatus, two wild birds have tested positive for the H5N1 serotype in Israel. Detected to two different districts, the virus involved belonged to clade 2.3.4.4b of fully Eurasian lineage.
During December, two wild birds of the duck/goose family were found dead at a lake in southwestern Kazakhstan. According to the WOAH notification, they tested positive for the H5N1 HPAI virus. These were the country’s first cases since the previous outbreak series ended in July of last year.
View our continuing coverage of the global avian influenza situation.
