As Japan confirmed the first detection of the H5N6 serotype of the highly pathogenic avian influenza (HPAI) virus in poultry for six years, further outbreaks have been confirmed in South Korea.
The presence of the virus was confirmed after a few birds died out of two related flocks of around 14,000 broiler breeders, according to the official notification to the World Organisation for Animal Health (WOAH).
Located in the Minamisatsuma city area in Kagoshima prefecture, the two flocks were epidemiologically linked. The source of the infection is unknown.
This is the country’s ninth HPAI outbreak of the season, and it occurred on the most southwestern main island of Kyushu.
Just a few days previously, the Japanese authority had registered two further HPAI outbreaks in poultry linked to the H5N1 HPAI virus.
At the end of January, some of the 24 birds in a backyard flock tested positive for the virus. Affected was a premises in Yamaguchi prefecture in western Honshu.
Soon afterwards, the infection was confirmed among more than 103,700 birds in two epidemiologically linked farms in Kagawa. This prefecture is located on Shikoku, a large island south of Honshu.
As well as the H5N6 virus recently detected, Japan has registered eight HPAI outbreaks in poultry linked to the H5N1 serotype so far this winter.
Since November, around 654,000 poultry in Japan have been impacted by disease linked to the H5N1 virus variant.
Japanese authorities have also registered with WOAH cases in wild birds that have tested positive for the H5N1, H5N5, and H5N6 serotypes.
6 more poultry outbreaks in Taiwan
In its latest notification to WOAH, Taiwanese authorities have confirmed five more outbreaks linked to the H5N1 virus.
All of these began in January, and hit farms in the county of Yunlin. Involved were two flocks each of meat ducks and native chickens, and one of meat geese.
These brought to 10 the number of outbreaks in the territory since November of last year. Directly impacted have been more than 91,000 commercial poultry.
Furthermore, Taiwan News has since reported that around 9,600 native chickens have been culled in Pingtung county. After a spike in mortality, they had tested positive for the same virus variant.
HPAI hits Cambodian village flocks again
Following a brief hiatus, the H5N1 HPAI virus has been detected again in village poultry in Cambodia.
Based on the latest reports to WOAH, birds first tested positive for the virus in the southern province of Prey Veng on January 24. By the first week of February, two further outbreaks were confirmed — firstly in the northwestern province of Siem Riep, and then in Kratie in the northeast of the country. So far, the number of backyard poultry involved has passed 3,900.
The previous outbreak series linked to the same virus variant was declared ended in January. It had involved around 3,000 poultry in six village flocks across five provinces, including Prey Veng and Siem Riep.
Outbreaks on 2 South Korean poultry farms
In December of last year, South Korea reported its first cases of HPAI linked to the H5N6 virus serotype in poultry since 2018.
Total outbreaks in this population have risen to 26 with notifications to WOAH of the most recent two outbreaks in commercial ducks. These affected premises with 10,000 birds in South Jeolla, and 29,000 in South Chungcheong. There have been previous cases in both of these provinces.
Around the same time, South Korea recorded its first HPAI outbreaks linked to the H5N1 virus of the winter season.
So far, this serotype has been detected at five farms, bringing the nation’s total HPAI outbreaks for the season so far to 31. These have directly involved more than 2.08 million commercial poultry.
Avian flu developments in poultry elsewhere in Asia
Following a five-month hiatus, the H5N1 HPAI virus has been detected again in the Sakhalin region in Russia’s Far Eastern federal district.
According to the WOAH notification, presence of the virus was confirmed after more than 107,000 birds died out of total flock of over 294,000 birds. Source of the infection is unknown.
Sakhalin is a large island in Northeast Asia.
In two towns in the south Indian state of Andhra Pradesh, HPAI has been detected after thousands of poultry died, reported India Today last week. Chicken shops within a 10pkm radius of the outbreaks were immediately closed.
Subsequently, a Times of India report confirmed the presence of the H5N1 virus serotype in the Nellore district. Rearing of chickens in the two outbreak epicenters has been banned for a period of three months, and after that, flock sizes will be limited to no more than 20 birds.
The Philippines’ animal health authority has retrospectively reported to WOAH a further seven HPAI in poultry linked to the H5N1 virus in the Central Luzon region.
Starting in the period June 11 to November 30 were six outbreaks in backyard flocks, and one on a farm. Each of the individual outbreaks involved flocks of between five and 9,000 birds.
Since the first cases in this disease wave in January of 2022, WOAH has been notified of 256 outbreaks affecting a total of almost 2.1 million poultry in the Philippines.
Further human cases in Cambodia, Laos market closed
Earlier this month, the health agency of Cambodia informed the World Health Organization (WHO) about two human infections with the avian influenza A(H5N1) virus.
Both started in January. For a three-year-old boy in the southern province of Prey Veng, symptoms started on January 1. Later in the month, presence of the virus was detected in a 69-year-old man from Siem Reap in the northwest of the country.
Earlier this month, AvianFluDiary reported a further human case related to a virus of avian origin. This involved a nine-year-old boy in the northeastern province of Kratie, who has died from the infection. Investigations revealed that a number of chickens and ducks at the family home had died, and been eaten.
The case brings Cambodia’s total cases linked to this virus family in less than 12 months to nine. This is the highest total in any country within one year in any country since 2015.
All eight of the nation’s previous cases were linked to the 2.3.2.1c clade, which is an older form that generally circulated before the current dominant one, clade 2.3.4.4b, according to the same source.
In Laos, a live bird market in the capital city Vientiane was temporarily closed earlier this month.
According to FluTrackers, this followed the detection of H5N1 and H9N2 viruses in chicken, duck, and environmental samples at the premises.
China reports Influenza virus co-infection
Also in Asia, an unusual case has been reported in China.
A 63-year-old woman from the Xuancheng region of Anhui province became unwell at the end of November, and died the following month. It emerged that she had become infected with a seasonal flu virus (H3N2) and the H10N5 variant of avian origin, according to FluTrackers citing a report in People’s Daily.
The patient was a farmer, and had underlying health conditions. A few days before the onset of symptoms, she had bought a duck from a live bird market. Remains of the meal tested positive for the H10N5 virus.
According to WHO, avian influenza A(H10) subtype viruses are known to occur worldwide in birds. In both domestic and wild species, they are classed as “low pathogenic.” They have been found rarely to infect mammals such as pigs, but until now, infections in humans have been rare.
View our continuing coverage of the global avian influenza situation.
