Registering new cases of highly pathogenic avian influenza (HPAI) in poultry over the past week have been Japan, South Korea, Vietnam, and four European countries. The infection has also returned to domestic flocks in Egypt and Iran. New research reveals that four avian flu viruses currently circulating in Europe are closely related. In China, the latest human case of the disease has been fatal.
South Korean cases being investigated
In South Korea, the agriculture ministry is investigating three suspected outbreaks of HPAI in poultry. According to Yonhap, the infection was confirmed earlier this week in a flock of ducks and quails totaling 96,000 birds at Yongin, which is near to Seoul.
Since the country’s first case in poultry linked to the H5N8 virus variant at the end of November, 18 outbreaks in poultry have been reported to the World Organisation for Animal Health (OIE). Directly impacted by these outbreaks were more than 1.8 million poultry. Since the country's first cases in North Jeolla province, the virus has been detected in one or more locations in North Gyeongsang, South Jeolla, Gyeonggi, North Chungcheong, and South Chungcheong.
Yonhap reports that 6.1 million poultry — including 4.0 million chickens and 1.2 million quail — have been culled to halt the spread of infection. In South Korea, all poultry kept within three kilometers of a confirmed outbreak must be destroyed.
HPAI detected in 12 Japanese prefectures
In the past week, an H5 avian flu virus has been detected at poultry farms in Tokushima and Miyazaki. Tests are being carried out to identify the virus involved, and its pathogenicity. In the meantime, tens of thousands of poultry will be slaughtered, reports Kyodo News. In Tokushima — the 12th prefecture to have been affected by the disease so far this winter — there are 10 farms with 175,000 poultry within 3km of the infected premises. The latest outbreak in Miyazaki brings the prefecture’s total to eight, and 34,000 poultry will be culled. So far, all the outbreaks in Japan have been in the west of the country.
Last week, Japan Times reported a 12th outbreak in Kagawa, which is the prefecture where the first of this season’s cases were found. Around 29,000 poultry at the infected farm and a related premises were going to be culled.
Avian flu returns to Egypt, Iran
Presence of an avian influenza virus has been detected for the first time this season in Egypt. Poultry at two farms in the Dakhla Oasis have been affected, reports Asharq Al-Awsat. All birds at the affected premises have been culled.
In Egypt’s Western Desert, the Oasis is around 750km from the capital, Cairo. The virus family and pathogenicity are not given in the report.
Earlier this year, OIE declared Egypt free of avian influenza for the first time in 14 years.
During the first week of December, the H5N8 HPAI virus was detected in poultry in Iran for the first time since January.
Surveillance revealed the presence of the virus, according to the official report to the OIE. Involved in the outbreaks was a flock of 600 turkeys in a village in the Tehran region in the north of the country. Around 50 of the birds died, and the rest have been destroyed. Wild bird contact is suspected as the source of infection.
Further HPAI outbreaks in Vietnam
According to the agriculture ministry, three more outbreaks of HPAI linked to the H5N6 virus variant have been confirmed in village flocks. In total, more than 10,000 birds were affected. According to the OIE report, cases occurred in Thai Binh province (Red River Delta region), Khanh Hoa (South Central Coast), and Nghe An (North Central Coast).
Latest outbreaks bring the country’s total since the end of August to seven, involving 18,000 poultry in five provinces.
HPAI “resolved” in Australia
In its latest report to the OIE, the agriculture department has declared the HPAI situation “resolved.” This declaration followed the completion of decontamination at all three premises involved in outbreaks during July and August of this year. Over that period, a total of more than 435,000 commercial laying hens were involved. They belonged to three free-range flocks near Lethbridge in the state of Victoria.
Just one week previously, the same authority declared the resolution of two series of outbreaks of low-pathogenic avian influenza (LPAI).
Europe: Significant developments in the avian flu situation
In the United Kingdom (U.K.), the H5N1 HPAI virus has been detected for the first time in poultry. Affected was a small backyard flock near Hawes in North Yorkshire, according to the agriculture department (Defra).
After an absence of more than two years, the same virus variant has been found in The Netherlands. According to the official report to the OIE, the infection was found in a commercial flock of around 27,700 poultry at Buitenpost in the northern province of Friesland. Out of the flock, 150 birds died, and the rest have been destroyed. No other poultry are present within 3km of the infected premises.
Also after a prolonged period, Italy’s health ministry has reported to the OIE that wild birds have tested positive for the H5N1 HPAI virus. Last detected in the country in 2006, this virus has been found in two wild ducks in the Veneto region. In the same region, one sick wild duck has tested positive for the H5N5 HPAI virus. This virus variant was last detected in Italy in March of 2017.
Because of developments in the HPAI situation, Northern Ireland has become the last region of the U.K. to order all poultry to be housed. Coming into effect on December 23, the regulations also require all bird owners to maintain high levels of biosecurity, according to the agriculture department (DAERA). Main aim is to prevent contact with wild species, which are most likely to transmit the infection.
This winter’s first HPAI outbreak in poultry in Scotland has occurred on the island of Sanday, reports the Scottish government. A small commercial flock in the region of Orkney tested positive for the H5N8 HPAI virus last week.
Additional outbreaks in European poultry
Over the past week, eight new HPAI outbreaks linked to the H5N8 virus has been registered with the OIE by Poland. Directly involving almost 295,000 birds, the outbreaks occurred in the provinces of Greater Poland (Wielkopolskie), Warmia-Masuria, Mazovia, and West Pomerania (Zachodnio-Pomorskie). For the last of these provinces — in the northwest of Poland — this was the first outbreak of this season. All 320 birds in the flock died.
In Germany, an HPAI virus has been detected in a turkey. The bird was located in the northwest of the country — in Cloppenburg in the state of Lower Saxony — according to the Friedrich-Loeffler Institute. Restrictions have been put in place in the area.
Six European states register more cases of HPAI in wild birds
Over the past week, H5N8 HPAI has been detected among the wild populations of France (Upper Corsica and Bouches-du-Rhône), Denmark (66 locations), Germany (Schleswig-Holstein, Hamburg, Mecklenburg-West Pomerania, and Lower Saxony), Italy (Veneto), Poland (Pomerania and West Pomerania), and the U.K. (27 locations).
Meanwhile, wild birds in Mecklenburg-West Pomerania (Germany) have tested positive for the H5N5 HPAI virus.
Current European avian flu viruses have common source
Genetic analysis has revealed that all the H5 HPAI viruses belong to the same genetic group, according to the European Reference Lab for avian influenza, IZSVe. Furthermore, they all form a cluster with those viruses isolated in Kazakhstan and Russia since July of this year. They are also closely related to the H5N8 strain from Iraq (May 2020) and Egypt (since 2017). According to this source, it this suggests that the HPAI currently circulating in Europe originated in North Africa and south-west Asia.
Within the group of H5 HPAI viruses, IZSVe has found a series of distinct gene constellations. These are thought to have arisen as the result of reassortment with LPAI viruses in wild birds. The researchers identified five separate genotypes — one each for H5N8 and H5N1, and three H5N5 subtypes. Of these, four genotypes have been detected in Europe so far this winter season.
New human case in China
Earlier this month, one confirmed human case of avian influenza A(H5N6) was confirmed in China’s Jiangsu Province. According to the Centre for Health Protection in Hong Kong, the patient was an 81-year-old woman who has died. This latest case brings the total cases linked to this virus worldwide since 2014 to 25. All have been recorded in mainland China.
View our continuing coverage of the global avian influenza situation.
