In Australia, established responses to the H7 highly pathogenic avian influenza (HPAI) outbreaks continues, according to the national government’s dedicated website.
It reports that eight farms have confirmed infections in the state of Victoria, two in New South Wales, and one in the Australian Capital Territory (ACT; around Canberra). All of these premises have been depopulated, and the sites are undergoing decontamination processes.
Over the past two months, three different variants of HPAI virus have been isolated in the nation’s poultry.
The first outbreak in the nation’s commercial poultry was confirmed in mid-May, according to the official report to the World Organisation for Animal Health (WOAH). It was the first detection of the H7N3 HPAI virus serotype in the state of Victoria.
Within a few days, poultry at another location in the same state tested positive for the H7N9 virus. It represented the first ever detection of this variant in an Australian poultry flock although it was similar to viruses isolated from the country’s wild birds.
Then in mid-June, a flock of free-range laying hens in New South Wales tested positive for the H7N8 serotype. This variant had not been detected in Australia before.
Since those first reports, one more farm in Victoria has been hit by the H7N3 virus, according to WOAH notifications. Presence of this variant was confirmed on June 23 in a flock of more than 42,000 free-range laying hens in Lethbridge — near to premises with previously confirmed outbreaks.
Linked to the H7N8 virus variant have been two further outbreaks at around the same time. These impacted a flock of around 87,000 free-range broiler chickens in New South Wales — in the same district of Hawkesbury as the earlier outbreak in the state. On June 24, a flock of around 170,000 laying hens tested positive for the same virus. However, this housed flock was at Belconnen in ACT — more than 200km away from the other outbreaks in this series.
Subsequently, the Australian veterinary authority has reported to WOAH a fourth outbreak in this HPAI series covering H7N8 infections in commercial poultry.
Starting on July 8, this affected a small flock in Hawkesbury, New South Wales. While it comprised just 11 birds, the agency categorized it as a commercial premises because the owner sells eggs to the public.
Meanwhile, a separate disease series has been initiated with WOAH to cover outbreaks linked to the H7N8 HPAI virus in non-commercial poultry flocks.
According to the relevant WOAH notification, the virus is genetically related to the one of this strain affecting commercial poultry, as well as to cases in Australian wild birds.
As of June 30, birds in this category have tested positive for this virus at four locations — all near to the commercial outbreaks. Three of these were in the Hawkesbury district of New South Wales, and one in Belconnen in ACT. Affected so far have been a total of 13 birds in flocks, each comprising between one and five individuals.
Recent emergence of HPAI in Australia’s pet chickens has prompted some to call for the compulsory registration of hobby birds.
Currently, this is only a requirement in the Northern Territories, according to the Australian Broadcasting Corporation. However, officials in other states say that encouraging registration would help support biosecurity education and traceability.
H5N1 returns to regions of Bhutan, Cambodia
Following a five-month hiatus, this HPAI virus serotype was detected again in the south Cambodian province of Takeo in the first week of July.
According to the notification from the national animal health authority to WOAH, affected was a flock of 1,168 birds of a village flock. More than 470 of the poultry died, and the rest have been culled and their carcasses destroyed.
Between late January and early February of this year, the same virus variant was detected in three other village flocks in Cambodia, and officially registered with WOAH.
These outbreaks were widely dispersed across the country, affecting one village in each of Prey Veng, Siem Reap, and Kratie — provinces in the south, northwest and northeast of Cambodia, respectively.
In April of 2023, the veterinary agency in the Kingdom of Bhutan declared an end to a series of H5N1 HPAI outbreaks in the southwestern district of Samtse.
However, the virus was detected again in this southern district earlier this month, according to a recent WOAH notification. This outbreak appears to be close to the border with India.
Affected was a flock of around 4,000 village birds, more than one thousand of which died. Source of the infection is unknown.
Latest on HPAI situation elsewhere in Asia
At the end of June, the H5N1 HPAI virus was detected at two poultry farms in Taiwan.
Affected were a total of more than 53,000 meat chickens at two linked premises in the same township in Yunlin county, according to the official notification to WOAH. The farms were under the same ownership, and authorities were alerted when mortality jumped suddenly as feed intake and egg production dropped. The virus was reported as belonging to clade 2.3.4.4b, and of fully Eurasian origin.
Authorities in Taiwan had recently closed an earlier HPAI disease series linked to a virus of the same origin and type. Between November of 2023 and June of this year, reports to WOAH linked it to 40 farm outbreaks involving a total of around 539,000 poultry in the territory.
In the Philippines, there appears to be an easing in the number of new HPAI outbreaks in poultry.
The disease situation is now on-going in just one province and region — Pampanga in Central Luzon. There are active outbreaks linked to the H5N1 HPAI virus at three farms in two municipalities in this area, according to the Department of Agriculture (DA) Bureau of Animal Industry (BAI).
Despite the localized nature of the ongoing outbreaks, an increase in the country’s poultry meat imports so far this year has been partly attributed to the impacts of HPAI. The disease — combined with the effects of El Nino — reduced poultry production, reported the official Philippine News Agency.
Just last week, the same source reported that the DA and BAI are warning people in the Philippines against purchasing bird flu vaccines through online platforms or other unregulated channels.
As well as being illegal, these products pose a risk to the health of both people and poultry, said a senior DA official.
To WOAH, Russia’s veterinary agency has declared the H5N1 HPAI situation “resolved” in one region of its Far Eastern federal district. The declaration followed a single outbreak at a large commercial poultry farm in the Sakhalin region, which started in early February.
Three new human influenza cases in Asia
Over the past month, the World Health Organization has been informed about three new human infections with avian influenza A virus in the Western Pacific region.
Two of these were detected in children in Takeo province in Cambodia. Early in July, a three-year-old boy was admitted to hospital, and subsequently tested positive for influenza A(H5N1). Through contact tracing, a five-year-old girl was traced. Although she had no symptoms, she also tested positive for the virus, and isolated and treated in hospital.
In mid-June, a patient in Guizhou province in China developed influenza-like symptoms. Since testing positive for influenza A(H9N2) virus, the 31-year-old woman tested positive, and has recovered.
View our continuing coverage of the global avian influenza situation in poultry, and on disease developments in the U.S..
