Despite ongoing sporadic highly pathogenic avian influenza (HPAI) outbreaks, Japan was able to resume poultry product exports to Singapore in early May, according to the country’s agriculture ministry.

At the time, this applied to 10 of the country’s 12 prefectures where HPAI outbreaks had been confirmed. This resumption of trade was facilitated by agreement by the two states regarding compartmentalization.

Over the past month, six further outbreaks of HPAI linked to the H5N1 virus serotype have been officially confirmed by Japanese authorities.

According to notifications to the World Organisation for Animal Health (OIE), these outbreaks started between mid-April and mid-May. Affected have been three flocks of laying hens — each with 400, 760 and 520,000 birds — and one farm with 110,000 broiler chickens. Other affected premises were a zoo and a breeding facility, both with emus and/or ostriches.

Three of these locations were in Hokkaido (the country’s most northerly large island). Others were in different prefectures in the Tohoku region in northern Honshu.

Together, these bring to 23 the number of Japan’s HPAI outbreaks linked to this virus since the November of 2021. Affected through mortality or culling to prevent further spread of the infection have been almost 1.74 million of the nation’s poultry.

In addition, there was two HPAI outbreaks linked to the H5N8 serotype in Japan at the start of the 2021-2022 winter. These involved a total of 154,000 poultry.

Poultry numbers recover in the Philippines

According to the Philippines Statistical Authority, national poultry production was 12% higher in the first quarter of 2022 than in the same period last year. Increases were registered for all poultry types except ducks.

In more good news for the sector, the animal health agency has officially declared the HPAI situation related to the H5N8 HPAI virus “closed.” This serotype was detected at one duck farm in Central Luzon during February of this year.

However, 13 further outbreaks linked to the H5N1 serotype have been reported to the OIE over the past month. Affected were six duck flocks, six of mixed species, and one of laying hens.

Of these, nine involved farms and backyard flocks on the island of Luzon. More than 14,000 poultry were impacted by these outbreaks across five provinces between early March and April 12.

Meanwhile, three of the latest outbreaks affected flocks on the island of Mindanao. Furthermore, first HPAI cases were reported in Maguindanao, which is part of the Bandsamoro Autonomous Region in Muslim Mindanao.

Since the first cases in these current outbreak waves were reported in January, OIE has been notified about 67 outbreaks in the Philippines’ poultry flocks. Affected have been around 174,700 birds.

With the continued spread and detection of HPAI, provinces and regions free of the infection so far are working to maintain their disease-free status.

So just last week, the Philippines News Agency (PNA) reported that the Davao region in southeastern Mindanao has banned the entry of all poultry from HPAI-infected areas. The ban covers all domestic birds and their products. Controls are being enforced by the establishment of new checkpoints at key border locations.

Meanwhile, in Western Visayas, authorities for Iloilo province have introduced a quarantine requirement for selected poultry from all areas with HPAI infections. This now also covers much-needed replacement pullets. Starting from the start of May, PNA reports, all poultry must be quarantined at a specified quarantine facility for 14 days prior to entry to the province. Furthermore, the source farm must have a certificate of a negative HPAI virus test within 21 days of shipping.

At the end of April, Pangasinan province (Ilocos region in northwestern Luzon) banned the entry of poultry from the Cagayan region in the northeast of the island. This followed confirmation of H5N1 HPAI as the cause of death in 200 poultry in Isabela province in the latter region. PNA reported previously that Pangasinan had halted incoming shipments of quails and ducks from two provinces in Central Luzon because of confirmed HPAI cases at four farms.

Large commercial flock hit by HPAI in Nepal

With confirmation of a new infection at the end of April, Nepal’s total outbreaks since January stands at 33. Directly impacted at infected premises have been around 272,500 poultry, including 212,700 mortalities.

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Latest premises to be hit by the H5N1 HPAI virus serotype was a commercial farm with 116,000 laying hens, according to the OIE report. Around 2,000 of the birds died at the premises, which was in the Chitwan district in Narayani province. Previous cases have been detected in this area.

Since that outbreak, another has been confirmed in the Sarlahi district in Madesh province. The Himalayan Times reports that HPAI was confirmed after 382 of the 550 ducks at the farm died over the previous 10 days. No other farms or settlements are located nearby. 

HPAI detected at Taiwan slaughterhouse

Following observation of suspicious signs, tests at a slaughterhouse in the Wanhua district of Taipei city revealed the presence of the H5N2 HPAI virus.

Affected was a group of 11 native chickens in mid-April, according to the OIE report. The carcasses were destroyed, and the factory was cleaned and disinfected. Birds were traced back to the farm of origin for further investigation.

Taiwan’s first HPAI cases in the current outbreak wave were reported by the territory’s authorities in November of 2021. Since then, 32 outbreaks have been linked to this virus serotype. Directly impacted have been around 445,000 poultry.

HPAI situation among Asian wild bird populations

Following a 12-month hiatus, the H5N8 HPAI virus was detected again in Israel’s wild bird population in mid-April. This is according to the latest notification to the OIE from the nation’s animal health agency.

Up to early May, two more birds tested positive for this variant in different regions of the country.

Meanwhile, the agency considers an earlier disease event linked to the H5N1 virus to be “closed.” More than 8,000 wild birds — mainly pelicans — died with this infection between November of last year and February.

For the first time, a wild bird has tested positive for the H5N1 virus serotype in the Khabarovsk region in Russia’s Far Eastern federal district. Affected was a single crow, according to the OIE report.

Over the past month, 130 more wild birds in Japan tested positive for the same virus variant. Latest OIE notifications mention positive cases in 125 crows, and several birds of prey. Recent cases are mainly concentrated in the prefectures of Hokkaido and Iwate. 

First human H3N8 infection reported in China

In April, the world’s first lab-confirmed infection with the avian influenza A(H3N8) was reported in China. According to the notification to the World Health Organization (WHO), the patient was a four-year-old boy from Zhumadian city in Henan province.

The boy became ill in early April, and was admitted to hospital on April 10. As the report was submitted to the WHO during the first week of May, the child's condition remained critical.

Prior to his illness, he had contact with chickens raised at his home, and had cooked and eaten chicken. None of his relatives or close contacts shows signs of infection.

On the available evidence, WHO assesses the risk at the national, regional, and international levels of disease spread as low. The agency will review this assessment, if and when further information becomes available.

Last week, Hong Kong’s Centre for Health Protection reported a new human infection of avian influenza A(H5N6) in Mainland China.

The 49-year-old man from Baise city in Guangxi province developed symptoms in mid-April after visiting a live poultry market. Following admission to hospital, he died on April 24.

Since 2014, 78 human infections linked to this virus serotype have been confirmed to the WHO by Chinese health authorities.

View our continuing coverage of the global avian influenza situation.