Australia: H5N1 Positive Bird Detections (n=102) Continue to Rise

 

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The number of confirmed H5N1 detections in wild birds in Australia has more than quintupled in a little over a week, rising from 20 on July 27th to 102 today (Aug 4th). 

Most of this increase has come from the state of South Australia, where the first mass mortality event (in birds) has been confirmed.

Two quick updates this morning from the Australian Authorities, first this from DAFF.

Attributable to Australian Chief Veterinary Officer, Dr Beth Cookson:

Testing at CSIRO’s Australian Centre for Disease Preparedness (ACDP) has confirmed further positive results in South Australia, bringing the total to 81 in South Australia. This includes detections in Limestone Coast (Southend, Robe and Baudin Rocks), Kangaroo Island (Harriet River, Seal Bay, Vivonne Bay and D’Estrees Bay), Coorong, Glenelg, Troubridge Island and The Pages Islands. It also includes 6 from Baudin Rocks, comprising 5 greater crested terns and 1 silver gull.

The Baudin Rocks detection follows an investigation into over 80 sick or dead wild birds, and is the first confirmed mass mortality event in wildlife in Australia due to H5 bird flu.

In line with overseas experience and recent events within Australia, a mass mortality event is not unexpected. It follows evidence of some local transmission between a smaller number of wild birds in South Australia.

There has also been one further positive result from Portland in Victoria at this stage, through testing at its state laboratory.

There have now been 102 confirmed or presumed positive detections of H5 bird flu in Australia, based on samples tested. With the mass mortality event at Baudin Rocks, not all sick or dead wild birds were sampled as this is not necessary to determine whether the event was due to H5 bird flu.

There remain no detections in poultry or in our agricultural production system.

The risk to human health remains low.

And from SA state authorities we get:

Current bird flu detections

South Australia’s first confirmed detection of H5 bird flu was in a wild migratory bird (southern giant petrel) on Wednesday, 24 June at Knights Beach at Port Elliot on the Fleurieu Peninsula.

Further confirmed detections include: 

• a giant petrel (8 July at Hardwicke Bay, Yorke Peninsula)
• a southern giant petrel (10 July at Emu Bay, Kangaroo Island)
• a northern giant petrel (10 July at Port Vincent, Yorke Peninsula)
• three greater crested terns (10 July at Robe, Limestone Coast; 26 July at Semaphore, metro Adelaide; and 26 July at Robe, Limestone Coast)
• seven greater crested terns (28 July at Cape Jaffa, Port MacDonnell and Southend, Limestone Coast)
• a giant petrel (30 July at Port Lincoln, Eyre Peninsula)
• a silver gull (1 August at Robe, Limestone Coast)
• 19 greater crested terns (1 August at Beachport (3), Cape Jaffa (1), Southend (1), Port MacDonnell (2), Robe (7), Limestone Coast; and Seal Bay (5), Kangaroo Island)
• two silver gulls (2 August at Robe (1) and South End (1), Limestone Coast)
• a greater crested tern (2 August at Monarto)
• a petrel (3 August, Coorong)
• one silver gull (3 August, Glenelg)
• two greater crested terns (3 August, Troubridge Island)
• one silver gull (3 August, Southend)
• one greater crested tern (3 August, Monarto)
• six greater crested terns (3 August, Pages Island)
• five greater crested terns (3 August, Baudin Rocks)
• one silver gull (3 August, Baudin Rocks).
• 23 greater crested terns (4 August, Limestone Coast, Southend (5) and Robe (7), and Kangaroo Island, Harriet River (1), Seal Bay (4), Vivonne Bay (5) and D’Estrees Bay (1)

A further 28 suspected H5 bird flu detections are undergoing further confirmatory testing at the Australian Centre for Disease Preparedness in Victoria.

Up-to-date national information is available at birdflu.gov.au.

Given the limits of surveillance and testing, the real number is likely much higher, potentially in the thousands by now.  For now, all detections have been in migratory or native seabirds, but how long that status quo can continue remains to be seen.  

Mainland China, Taiwan & Hong Kong All Reporting Summer Surge of COVID

 
Credit China CDC  (translated by google)

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While we've enjoyed a prolonged lull in COVID activity here in the United States, the same can't be said for everyone. As we noted 3 weeks ago, both Hong Kong and Taiwan were reporting a summer uptick in COVID cases. 

Reassuringly, in their latest update (July 31st), the CDC continues to report very low respiratory illness in the United States, but indicates that - unlike with Flu and RSV - COVID activity is slowly rising.

Where COVID is Increasing (CDC 7/31/26)

By contrast, this week China is reporting 20% COVID positivity (see chart at top of blog) among influenza-like illnesses seen at sentinel hospital outpatient and emergency departments, while last week Hong Kong reported:

`The latest surveillance data showed that local COVID-19 activity is currently in an active period and remains at a relatively high level.'

Today Taiwan's CDC is reporting an additional surge in serious (and even fatal) COVID-19 cases, and is urging the public to get vaccinated and take extra precautions to avoid infection. 

With the domestic COVID-19 epidemic rising and currently in its epidemic period, we urge those who have not yet been vaccinated to get vaccinated as soon as possible and to implement self-protective measures such as frequent handwashing and wearing masks.

Release Date: 2026-08-04

The Centers for Disease Control (CDC) stated today (August 4th) that the domestic COVID-19 epidemic continues to rise and is in its epidemic period. The CDC urges the public not to let their guard down and to take good self-protection measures, including frequent handwashing; wearing masks when entering and exiting medical care facilities, taking public transportation, and going to crowded indoor places; if experiencing fever or respiratory symptoms, it is recommended to stay home as much as possible and avoid unnecessary outings, remembering to wear a mask when going out; those who have not yet been vaccinated should get vaccinated as soon as possible; and those with other risk factors for severe illness should seek medical attention immediately if they experience suspected symptoms, so that doctors can diagnose and treat them early and prescribe antiviral drugs, reducing the risk of severe complications or death after infection.

According to CDC monitoring data, the domestic COVID-19 epidemic is rising. In the 30th week (July 26th - August 1st), there were 18,990 outpatient and emergency room visits for COVID-19, an increase of 74.8% compared to the previous week (July 19th - July 25th); last week (July 28th - August 3rd), there were 62 new local severe cases and 3 local deaths.

Since October 2025, there have been a total of 265 local cases of COVID-19 complicated by severe illness, of which 28 have died. The majority of severe cases are among those aged 65 and above (74.0%) and those with a history of chronic diseases (85.3%). 89.1% of these cases have not been vaccinated this season. In the past four weeks, the predominant variant strain in local cases is PQ.16.1.1.

The global positivity rate is trending upward, with the US and Europe showing a slight increase from their lows, while Southeast Asia and the Western Pacific are at a plateau. The epidemic continues to rise in China, the US, and the UK; the epidemic is declining weekly in Hong Kong, Japan, and Thailand. Recently, the predominant global variant strains are NB.1.8.1, XFG, and JN.1.

The Centers for Disease Control (CDC) points out that as of August 2, 2026, approximately 1.772 million COVID-19 vaccinations have been administered this season, with vaccination rates among those aged 65 and above at 21.12% for the first dose and 0.78% for the second dose. Taiwan has approximately 165,000 doses of COVID-19 vaccine in stock. 80,550 doses were allocated to various counties and cities for vaccination on July 30th, and an additional 45,000 doses are expected to be distributed on August 6th based on demand.

(Continue . . . )

 While all remains relatively quiet here, the CDC has produced a forecast of sorts; one which suggests that a late summer surge is possible, particularly in areas which saw lower COVID activity last winter.

National Outlook

While the past several waves have shown a trend of declining hospitalizations nationally, it remains possible that there could be a larger increase this summer. There is regional variability in both the timing and magnitude of COVID-19 activity. We developed two COVID-19 modeling scenarios for the summer to demonstrate the range of possibilities for how COVID-19 activity could unfold nationally. 

One scenario assumes that no variant with significant immune-escape properties emerges; the other is based on the possible emergence of a variant with moderate immune-escape properties that achieves predominance. The latter scenario is based on the characteristics that were observed in variants that emerged in the United States in the pastA.

While not specifically modeled in this scenario, we note that since its first detection in the U.S. in 2025, there have been detections of BA.3.2 in at least 29 U.S. states and Puerto RicoB. These modeling results show that in the absence of the emergence of a variant with moderate immune-escape properties, we do not expect an increase substantially larger than that experienced this past winter (Figure 2). If such a variant does emerge, there is substantial uncertainty (Figure 2), but modeling suggests increases would likely be within the range of what has been observed in the past 3 years (Figure 1).

Whether COVID-19 will increase significantly in the short-run here in the U.S. is unknown - but given its continued evolution and proven affinity for infecting humans -  it seems unlikely that we've seen the last of this troublesome virus. 

Australia Confirms First Mass Mortality Event (Birds) on Baudin Rocks Island

Video: @abcnewsaustralia
 

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While there was little doubt of the outcome, for the past 2 days we've been waiting for test results from an apparent mass mortality event on Baudin Rocks island, South Australia.  

Overnight South Australia has reported that HPAI H5N1 was detected in a number of sampled carcasses.

Those results were announced by Agriculture Minister Julie Collins (video link), and we have the latest update from South Australia.

Current bird flu detections

South Australia’s first confirmed detection of H5 bird flu was in a wild migratory bird (southern giant petrel) on Wednesday, 24 June at Knights Beach at Port Elliot on the Fleurieu Peninsula.

• Further confirmed detections include:a giant petrel (8 July at Hardwicke Bay, Yorke Peninsula)
• a southern giant petrel (10 July at Emu Bay, Kangaroo Island)
• a northern giant petrel (10 July at Port Vincent, Yorke Peninsula)
• three greater crested terns (10 July at Robe, Limestone Coast; 26 July at Semaphore, metro Adelaide; and 26 July at Robe, Limestone Coast)
• seven greater crested terns (28 July at Cape Jaffa, Port MacDonnell and Southend, Limestone Coast)
• a giant petrel (30 July at Port Lincoln, Eyre Peninsula)
• a silver gull (1 August at Robe, Limestone Coast)
• 19 greater crested terns (1 August at Beachport (3), Cape Jaffa (1), Southend (1), Port MacDonnell (2), Robe (7), Limestone Coast; and Seal Bay (5), Kangaroo Island)
• two silver gulls (2 August at Robe (1) and South End (1), Limestone Coast)
• a greater crested tern (2 August at Monarto)
• a petrel (3 August, Coorong)
• one silver gull (3 August, Glenelg)
• two greater crested terns (3 August, Troubridge Island)
• one silver gull (3 August, Southend)
• one greater crested tern (3 August, Monarto)
• six greater crested terns (3 August, Pages Island)
• five greater crested terns (3 August, Baudin Rocks)
• one silver gull (3 August, Baudin Rocks).

A further 49 suspected H5 bird flu detections are undergoing further confirmatory testing at the Australian Centre for Disease Preparedness in Victoria.

The current national tally sits at 78 confirmed detections, but that undoubtedly underrepresents the current situation.  There are literally thousands of citizen reports of bird deaths that have not been investigated. 

This update from https://www.agriculture.gov.au/campaigns/birdflu

Detection of H5 bird flu 

As of 3pm AEST, 3 August 2026, Australia has 78 confirmed detections of H5 bird flu in wild seabirds.

• 10 in Western Australia (WA)
• 58 in South Australia (SA) 
• 2 in New South Wales (NSW)
• 1 in Queensland (QLD)
• 7 in Victoria (VIC).

This is the serious H5 bird flu strain that has been circulating globally.

There have been no detections in poultry or the wider agriculture industry. There is no evidence of any large scale deaths. 

The Consultative Committee for Emergency Animal Disease (CCEAD) has reviewed its previous advice and endorsed a framework on national poultry biosecurity measures that will commence from 31 July. Under this framework, state and territory governments are responsible for issuing advice on biosecurity measures using a risk-based approach.

State and territory governments are responsible for surveillance and response activities on the ground. They are actively working with industry to provide guidance on implementation of enhanced biosecurity measures, as appropriate. Find out more about bird flu in your state or territory.

National coordination is being led by the Department of Agriculture, Fisheries and Forestry (DAFF).

The risk to human health remains low.

Australia is well prepared to respond quickly.

While Australian national and local governments continue to stress the lack of outbreaks in poultry or other livestock, and still maintain `There is no evidence of any large scale deaths', the recent history of H5N1 suggests those types of reassurances are likely to be short-lived. 

Australia: Updated H5N1 Detections In Wild Birds (n=62)

 

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While we are still awaiting results from the mass mortality event on Baudin rocks, CSIRO has confirmed 3 more South Australian birds positive for H5N1, and Victoria's total has jumped to 7. 

These are just confirmed cases, and likely represent just a fraction of HPAIs spread throughout the nation.  Due to the logistics of recovering bird carcasses, and limited testing capacity, the backlog of uninvestigated citizen reports on dead birds has grown well into the thousands. 

As we discussed a little over 2 weeks ago, the number of daily reports were already far outpacing their ability to investigate and test carcasses.

 Graphic generated by Gemini

 Yesterday SA Chief Veterinary Officer Skye Fruean was quoted as saying:

"At some point in time and we're not there yet, we will stop testing in areas where we know it [bird flu] is well established … because there is nothing we can do to stop the spread, we don't need to continue testing in an area that we know it is present."

Since it is a weekend, reporting is sparse. But we do have the following update from https://www.agriculture.gov.au/campaigns/birdflu.

 

Detection of H5 bird flu 

As of 5pm AEST, 2 August 2026, Australia has 62 confirmed detections of H5 bird flu in wild seabirds.

• 10 in Western Australia (WA)
• 42 in South Australia (SA) 
• 2 in New South Wales (NSW)
• 1 in Queensland (QLD)
• 7 in Victoria (VIC).

This is the serious H5 bird flu strain that has been circulating globally.

There have been no detections in poultry or the wider agriculture industry. There is no evidence of any large scale deaths. 

The Consultative Committee for Emergency Animal Disease (CCEAD) has reviewed its previous advice and endorsed a framework on national poultry biosecurity measures that will commence from 31 July. Under this framework, state and territory governments are responsible for issuing advice on biosecurity measures using a risk-based approach.

State and territory governments are responsible for surveillance and response activities on the ground. They are actively working with industry to provide guidance on implementation of enhanced biosecurity measures, as appropriate. Find out more about bird flu in your state or territory.

National coordination is being led by the Department of Agriculture, Fisheries and Forestry (DAFF).

The risk to human health remains low.

Australia is well prepared to respond quickly.

Finland Reports 1st ASF Detection - Switzerland Investigating Unidentified Bovine Disease

Note: Many countries are slow or reluctant to report outbreaks.

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Although we spend most of our time looking at zoonotic diseases in this blog, over the years we've also followed a number of emerging and reemerging agricultural diseases, including: 

African Swine Fever In China: Epizootic or An EpicZootic?

Viruses: Novel Rodent Coronavirus-like Virus Detected Among Beef Cattle with Respiratory Disease in Mexico

Viruses: Influenza D in Domestic and Wild Animals 

There are also agricultural diseases that inhabit the middle ground, in that they can infect humans - but do so only rarely or have little or no epidemic or pandemic potential - such as the NWS screwworm, Newcastle disease, and Orf Virus (to name a few).

And sometimes, as was the case of 2024's Curious Reports of Unknown Disease In Dairy Cows (Texas, Kansas & New Mexico) - which was later confirmed to be HPAI H5N1 - an outbreak in livestock can pose a risk to humans.  

But even without a zoonotic component, these diseases can pose substantial economic and public health risks, including raising food insecurity issues (see COCA Call: Diseases of Food Animals Threaten Global Food Security).

Arguably, one of the most devastating non-zoonotic diseases is African Swine Fever (ASF), which has spreading across Europe for the past 2 decades, and reached China/Asia in 2018-2019 causing the loss of tens of millions of pigs. 

This week Finland reported their first detection of ASF in wild boars near the Russian border. This from the Finnish Food Authority:

African swine fever detected in Eastern Finland

July 31/2026

Preliminary tests have confirmed African swine fever (ASF) in wild boars in Virolahti, Eastern Finland. The Finnish Food Authority will verify the result with the EU’s reference laboratory for African swine fever in Spain. Measures to limit the spreading of the disease will be taken immediately. This is the first time that the disease has been detected in Finland. This disease is not contagious to humans.

The Finnish Food Authority has established an infection zone around the area where the finding was made, and the movement of pigs in the zone is restricted. The goal is to determine the prevalence of the disease in wild boars in the area and to prevent the disease from spreading elsewhere in Finland. You can find a map of the infection zone and the content of the current restrictions on the Finnish Food Authority’s website.

The virus causing African swine fever was detected in wild piglets that were found dead. The remains of three dead piglets were found by a local who delivered them to the Finnish Food Authority. The carcasses were found close to each other in Vaalimaa, Virolahti. A preliminary ASF virus finding was made in the Finnish Food Authority’s tests on Thursday 30 July.

The press release will be expanded

For more information, contact the Finnish Food Authority:
Sirpa Kiviruusu
Head of Unit
Animal Health and Medication Unit
tel. +358 40 092 0503
sirpa.kiviruusu@ruokavirasto.fi

Yesterday Pathfinder on FluTrackers posted an AFP report on a unidentified disease being reported in Swiss dairy cows, which led me to the following statement by the Swiss FSVO (Federal Office for Food Safety and Veterinary Affairs):

(translation)

Announcement published on July 31, 2026
Diseases in dairy cows: BLV is monitoring the development

Reports of fever, diarrhea, and significant drops in milk production are increasing in dairy cows. Investigations are underway with veterinarians, industry representatives, universities, laboratories, and veterinary authorities.

The Federal Food Safety and Veterinary Office (FSVO) is aware of reports of an increase in illnesses among dairy cows. Several farmers are reporting symptoms, particularly fever and diarrhea, often accompanied by a significant drop in milk production. The cause has not yet been identified. Investigations are underway into both metabolic and potential infectious causes. These investigations are being conducted in collaboration between practicing veterinarians, Cattle Health Switzerland, veterinary universities and laboratories, and the veterinary authorities.

So far, no pathogen has been identified as the infectious cause. A direct link between the current heat wave and the reported cases of diarrhea has not yet been established. However, high temperatures pose a significant stress, especially for high-yielding dairy cows, and can make the animals more susceptible to disease.

During heat waves, the animals must therefore be consistently protected from heat stress, especially through sufficient water, shade and suitable cooling measures.

Nonspecific symptoms such as fever, diarrhea, or decreased performance can also indicate a highly contagious animal disease. Animal owners should therefore inform their veterinarian immediately so that the necessary examinations can be initiated if required.

The Federal Food Safety and Veterinary Office (FSVO) is monitoring the situation together with the relevant specialist agencies and is continuously assessing it. Should further action be required, the necessary measures will be examined.

While this may turn out to be a heat-induced illness, or something common like Bovine Viral Diarrhea Virus (BVDV), the fact that no cause has been immediately determined makes this worth watching. 

Six weeks ago, in FAO calls for stronger prevention and global action as transboundary animal diseases spread across regions, we looked at the growing risks from the spread of agricultural diseases. 

Our health, and in many ways our fate, is inexorably intertwined with the global biosphere - making what happens in a Fruit bat in Bangladesh, a Shrew in China - or a cattle herd in Europe - something that that has the potential to change our world overnight. 

Australia: SA Confirms 19 More Birds with H5N1 - Mass Mortality Event On Offshore Islet - Victoria Update

 

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While Australia's first detection of H5N1 was in in Western Australia, and at least 5 states have now reported infected birds, South Australia has quickly become the epicenter of bird flu activity.  

Overnight another 19 suspected cases (mostly crested terns) were confirmed by the National lab (CSIRO), and we are now hearing about a mass mortality event on a small island (Baudin Rocks) just off the coast.

Details are provided on the Government of South Australia website:

H5 bird flu testing update

The Australian Centre for Disease Preparedness (ACDP) has confirmed positive test results for H5 bird flu in a silver gull at Robe and 19 greater crested terns on the Limestone Coast and Kangaroo Island.

There have now been 39 confirmed positive H5 bird flu cases in South Australia.

The 19 confirmed cases in greater crested terns were announced last night by the Australian Chief Veterinary Officer.

These greater crested terns were found in Beachport (3), Cape Jaffa (1), Southend (1), Port MacDonnell (2), Robe (7), and Seal Bay (5). One greater crested tern that returned a suspected positive result has returned a negative result in confirmatory testing by the ACDP.

A further six suspected H5 bird flu cases have been detected, all in wild seabirds, following testing of samples in Adelaide:

• 2 greater crested terns from Troubridge Island (off the east coast of the Yorke Peninsula)
• 1 greater crested tern from Monarto (Murray Bridge Council)
• 1 silver gull from Glenelg (Holdfast Bay Council)
• 1 silver gull from Robe (District Council of Robe)
• 1 silver gull from Southend (Wattle Range District Council).

The samples have been sent to the CSIRO’s Australian Centre for Disease Preparedness (ACDP) in Geelong, Victoria, for confirmatory testing with results expected to be known in the coming days.

There remains no H5 bird flu detections in poultry or other livestock. The risk to human health of H5 bird flu remains low.

PIRSA is also investigating a report involving 49 dead and 35 sick greater crested terns found by aerial surveillance teams yesterday at an offshore location south of Cape Jaffa. Samples were collected and are now undergoing testing in Adelaide, with results to be known in coming days.

Engagement with primary industries, the wildlife sector, and the broader South Australian community continues as part of the South Australian Government’s commitment to deliver the most comprehensive and effective wildlife and industry surveillance, reporting and preparedness efforts possible.

Baudin rocks, which local media has identified as the location of the mass mortality event, is a labeled a protected area under the Fauna Conservation Act of  1964 and is home to numerous species of birds. 

While H5N1 has not been confirmed, given the multitude of positive detections in the immediate area, HPAI is highly likely. 

Mass mortality events are common with HPAI, in birds and marine mammals, making this a concerning report (see Preprint: Mass mortality of southern elephant seals during multi-species outbreak of HPAI H5N1 on sub-Antarctic Heard Island).

While SA is currently the focus of our attention, neighboring state Victoria is now reporting at least 6 new presumed positive seabird detections. 

Further suspect H5 bird flu detections in south west

1 August 2026

Further suspect cases of H5 bird flu have been detected in crested terns in Victoria's south west.

There is now one existing positive case and six suspect cases in Victoria.

Preliminary testing has identified five crested terns, three from Portland and two from Nelson Bay, suspected to have H5 bird flu after returning a positive result at Victoria’s state lab, AgriBio. Samples are undergoing confirmatory testing at CSIRO's Australian Centre for Disease Preparedness along with the single suspect case from Portland announced yesterday.

Victoria's Chief Veterinary Officer Dr Graeme Cooke said the additional suspect cases showed how important community observations are in helping detect and monitor disease in wild birds.

        (Continue . . . ) 

There are literally thousands of citizen reports of dead or dying birds across Australia since H5N1's arrival in June; with South Australia reporting > 3,100 and Western Australia > 2,300. 

But due to logistics, and limited resources, only a fraction can been prioritized for investigation, and fewer still can be tested.  

What is becoming increasingly clear is that HPAI is encountering few barriers as it spreads through Australia's seabird population, and that marine mammals and poultry are at increasing risk as well.

WHO WPRO Reporting 4 More H9N2 Cases on Chinese Mainland

 

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Three days ago we looked at an HK report on 3 recent human infections with avian H9N2 on the Chinese Mainland (Guangxi Province, Jiangsu Province, Guangdong Province), all reported in late June.

Today, the WHO's WPRO (Western Pacific Regional Office) reports 4 more human infections, all occurring in the first half of July, making 7 H9N2 cases reported by China over a period of roughly 3 weeks. 

We've often discussed the difficulty in detecting cases, since most H9N2 infections are mild or moderate, and clinically indistinguishable from seasonal flu, meaning we've no idea how many cases we may be missing. 

As the following chart illustrates, case counts have been rising steadily in recent years, although it isn't known whether this trend is due to increased spillover of H9N2 to humans, or better surveillance. 

EFSA/ECDC Chart - Current To June 4th, 2026

With the addition of at least 9 additional cases to this chart, 2026 (n=22) appears on track to meet or exceed last year's record of 38 cases.  

The 7 cases from the last 2 reports are spread across 6 provinces, and most are said to have either direct or potentially indirect exposure to poultry. Of these seven cases, three adult patients reportedly had (unspecified) comorbidities and were hospitalized, while the four pediatric cases had mild illness. 

First the WHO WPRO update, after which I'll have a bit more on H9N2. 

Human infection with avian influenza A(H9N2) virus

From 24 to 30 July 2026, four new cases of human infection with avian influenza A(H9N2) virus were reported to WHO in the Western Pacific Region. All four cases were from China. The cases included;

• a 72-year-old female from Jiangxi Province with symptom onset on 5 July 2026;

• a 12-year-old male from Jiangsu Province with symptom onset on 6 July 2026;

• a 3-year-old female from Gansu Province with symptomonset on 11 July 2026;

• and a 58-year-old female from Yunnan Province with symptom onset on 13 July 2026. 

The four cases reported were geographically distinct from each other. One case reported direct exposure to live-poultry, while three had potential exposure related to live-poultry stalls or wet market visits. Two cases with underlying chronic respiratory disease conditions were hospitalized and subsequently discharged. The remaining two cases experienced mild illness, were not hospitalized and had recovered at the time of reporting.

Since 2015, a total of 177 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 174 were reported from China, two were from Cambodia, and one was from Viet Nam.

Most human infections with avian influenza A(H9N2) have been associated with exposure to infected poultry or contaminated poultry environments, and the majority of cases have been mild. Sporadic human infections continue to be expected in areas where H9N2 viruses circulate in poultry populations. Current evidence indicates that H9N2 viruses have not acquired the ability for sustained human-to-human transmission, and the risk of further community-level spread remains low. 

Despite being clearly zoonotic - LPAI H9N2 is considered a `non-reportable' disease in poultry or wild birds by WOAH (see Terrestrial Animal Code). As a result, there are huge gaps in surveillance and reporting around the world. 

At the same time we've seen a growing number of studies - mostly out of Asia - warning of its growing adaptation to mammalian hosts (see EM&I: Enhanced Replication of a Contemporary Avian Influenza A H9N2 Virus in Human Respiratory Organoids).

Last October the Chinese CDC Weekly published a detailed report (see Epidemiological and Genetic Characterization of Three H9N2 Viruses Causing Human Infections — Changsha City, Hunan Province, China, April 2025) which found:

Three children infected with H9N2 AIV were identified in Changsha in April 2025, and no epidemiological links were found between these mild and sporadic cases. Genetic analysis showed that the H9N2 viruses had enhanced binding ability to upper respiratory tract receptors, particularly the α2,6-sialic acid receptors.

The report goes on describe some of the notable HA mutations suggesting enhanced mammalian adaptation:

Analysis of receptor-binding sites showed that the HA proteins had mutations at amino acid positions H191N, A198V, Q226L, and Q234L, which potentially enhanced the binding ability of the virus to the receptor (5-6).

While there is still no evidence of sustained or efficient human-to-human transmission of H9N2, the virus remains poorly controlled in poultry, and  appears on a path towards greater mammalian adaptation. 

Our own CDC lists two lineages (A(H9N2) G1 and A(H9N2) Y280) as having at least some pandemic potential, and several candidate vaccines have been developed.

In terms of risk of emergence, the H9N2

Y280 lineage is ranked higher than H5N1

Whether H9N2 has true pandemic potential is unknown, but between acquiring new mammalian adaptations, and the ease with which it appears to be spilling over into humans, this is definitely a virus worth keeping our eye on. 

Australia: CSIRO Reports 4 H5 Positive Crested Tern Samples from Kangaroo Island

 
Credit Wikipedia

#19,270

No sooner has I posted my last blog when the following statement was posted on the Australian government website:

30 July 2026

Attributable to Australian Chief Veterinary Officer, Dr Beth Cookson:

Testing at CSIRO’s Australian Centre for Disease Preparedness (ACDP) has returned four positive results in crested terns, from Kangaroo Island, South Australia.

There have now been 33 confirmed or presumed positive detections of H5 bird flu in Australia.

All of these have been wild seabirds found in coastal locations.

There remains no evidence of any mass mortality events and there are no detections in poultry or in our agricultural production system.

The risk to human health remains low.

While not particularly surprising given its proximity to the other SA confirmed seabirds, this is a concern because Kangaroo Island is home to a number of marine mammals which are known to be susceptible to avian flu, including:

• Australian sea lion.

• Australian fur seal.

• New Zealand fur seal.

• Bottlenose dolphin and common dolphin. 

Last October H5N1 was detected on Australia's Heard Island - which we recently revisited in Preprint: Mass mortality of southern elephant seals during multi-species outbreak of HPAI H5N1 on sub-Antarctic Heard Island - which reported:

Drone surveys revealed mass mortality in southern elephant seals, with 8,573 pups (62%) recorded dead across Heard Island by the final surveys. Mortality increased at an average rate of 5.6% per day in a subset of harems, and the highest observed mortality in a harem was 97%. Based on the average (76%) mortality in the final surveys, total estimated pup mortality at Heard Island was 13,359 (from a total population of 17,364 pups), though this may be an underestimate as mortality was ongoing at this time. 

HPAI was detected in six of nine species tested and, we suspect, led to elevated mortality in king and gentoo penguins.

While there is currently no evidence of spillover into Kangaroo Island's marine or terrestrial mammalian population, this is another worrisome milestone for HPAI as it spreads across Oceania. 

Australia: H5N1 Reaches Victoria - SA `Suspect' Count Rises (n=24)

 


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A few hours ago Victoria announced their first H5N1 detection, once again in a greater crested tern, this time found in Portland. We've two announcements, first from Agriculture Victoria, and second by Australian Chief Veterinary Officer, Dr Beth Cookson announcing the confirmation from CSIRO. 

H5N1 avian influenza strain detected in Victoria

30 July 2026

The high pathogenicity avian influenza H5N1 strain (H5 bird flu) has been detected in Victoria.

Victoria’s Chief Veterinary Officer Dr Graeme Cooke said this detection is a result of Australia’s response to H5 bird flu, with the Victorian Government undertaking surveillance for the disease and working closely with the Commonwealth, interstate jurisdictions and industry partners.

‘Preliminary testing has indicated H5 bird flu in a single greater crested tern found in Portland. Further genetic testing is underway at CSIRO’s Australian Centre for Disease Preparedness at Geelong to formally confirm this result.’ Dr Cooke said.

‘This follows confirmation of the disease in seabirds in Western Australia, South Australia, New South Wales and Queensland, and the national decision that H5 bird flu is no longer technically feasible to eradicate in wildlife.’

‘Following weeks of enhanced readiness, we have now enacted Victoria’s State Emergency Animal Disease Response Plan. Based on international experience, this H5 variant differs from previous strains and has been known to cause large numbers of deaths in wild birds and some mammals.’

‘Our plans aim to limit impacts where possible particularly on our most threatened species, while also supporting our farmers and reducing risk to domestic and commercial poultry.

‘We need Victorians to avoid contact with sick or dead wildlife, record what they see and report it. Early reporting gives us the best chance to reduce the impacts of the disease,’ Dr Cooke said.

        (Continue . . . )

 

30 July 2026

Attributable to Australian Chief Veterinary Officer, Dr Beth Cookson:

Testing at CSIRO’s Australian Centre for Disease Preparedness (ACDP) has confirmed H5 bird flu in a greater crested tern, found in Portland in Victoria.

This is the first case in the state of Victoria.

There have now been 29 confirmed or presumed positive detections of H5 bird flu in Australia.

All of these have been wild seabirds found in coastal locations.

There remains no evidence of any mass mortality events and there are no detections in poultry or in our agricultural production system.

The risk to human health remains low

Meanwhile, South Australia has confirmed a 15th case (a Giant Petrel), and reports an additional 24 suspect cases are pending confirmation by CSIRO.

Current situation


South Australia’s first confirmed detection of H5 bird flu was in a wild migratory bird (southern giant petrel) on Wednesday, 24 June at Knights Beach at Port Elliot on the Fleurieu Peninsula.

Further confirmed detections include a giant petrel (8 July at Hardwicke Bay, Yorke Peninsula); a southern giant petrel (10 July at Emu Bay, Kangaroo Island); a northern giant petrel (10 July at Port Vincent, Yorke Peninsula); three greater crested terns (10 July at Robe, Limestone Coast; 26 July at Semaphore, metro Adelaide; and 26 July at Robe, Limestone Coast); seven greater crested terns (28 July at Cape Jaffa, Port MacDonnell and Southend, Lower South East); and a giant petrel (30 July at Port Lincoln, Eyre Peninsula).

A further 24 suspected H5 bird flu detections are undergoing further confirmatory testing at the Australian Centre for Disease Preparedness in Victoria.

The strain of virus is consistent with the strain detected in the Southern Indian Ocean Sub-Antarctic Territories, including Heard Island.

This strain has not been detected in poultry and has not become established in any part of Australia.

Up-to-date national information is available at birdflu.gov.au.

Although the official numbers remain reassuring low (n=29), they undoubtedly represent only a small fraction of actual H5 burden on wildlife in Australia.  Two weeks ago, we looked at the growing gap between reported events, prioritized and investigated cases, and lab testing in Western Australia. 

 Graphic generated by Gemini

I've not seen an update from WA since July 17th  - where total reports then exceeded 1,800 - and sadly, other states have not provided this sort of granular detail. 

But it is a fairly safe assumption that similar backlogs exist around the nation. 

Obviously, no surveillance and testing program can hope to capture more than a small fraction of the HPAI activity in birds or animals in the wild.  At best, it can give us some idea as to the spread, intensity, and host range of HPAI H5 across the continent. 

And right now, based on available data, H5N1 appears to be making significant inroads down under.  

EID Journal Dispatch: Seroprevalence of Influenza A(H5N1) Virus in Domestic Cats at Epicenter of Dairy Cattle Outbreaks, California, USA, 2024–2026

 

Seropositive cats around HPAI Infected Dairy Farm

#19,268

We've known for more than 2 decades that cats - both large and small - are susceptible to HPAI H5 infection (see 2004 CIDRAP Report) and have seen scattered reports over the years (see 2015's HPAI H5: Catch As Cats Can).

Until relatively recently, those reports were fairly rare, and mainly came from zoo animals fed on a diet of raw chicken. But since the emergence of a new, more transmissible clade 2.3.4.4b H5N1 virus in 2021, the number of companion animals (and other mammals) reported to be infected has risen sharply.

While undoubtedly underreported, more than 20% of all of the mammalian wildlife detections reported in the United States  (180 of 813 USDA reports) over the past 4 years have been among felines. 

Many have been reported in and around dairy and poultry farms (see EID Journal: HPAI A(H5N1) Clade 2.3.4.4b Virus Infection in Domestic Dairy Cattle and Cats, United States, 2024).

While many cats infected with HPAI sicken and die, others - based on seroprevalence studies (see Eurosurveillance: (HPAI) H5 virus Exposure in Domestic & Rural Stray Cats, the Netherlands, October 2020 to June 2023) - are likely only mildly affected and survive.

Previously, we've seen evidence of cattle-to-bird-to-cat transmission of avian flu, large outbreaks in animal shelters suggesting cat-to-cat transmission (H7N2), and limited evidence of cat-to-human transmission (see here and here). 

All of which brings us to a new dispatch, published yesterday in the EID Journal, which reports a 25% seropositivity rate among (n=12) cats sampled within 2 km of infected dairy farms, while no cats were seropositive further away (n=61).

While this is just one small, geographically limited, study the authors state: "Proximity to dairy farms in counties experiencing outbreaks may be a risk factor for H5N1 spillover to indoor and outdoor domestic cats."

I've only posted the highlights, follow the link to read the report in its entirety.

Volume 32, Number 9—September 2026
Dispatch
Seroprevalence of Influenza A(H5N1) Virus in Domestic Cats at Epicenter of Dairy Cattle Outbreaks, California, USA, 2024–2026
 
Ian G. Bemis, Ismaila Shittu, Jacob F. Gomez, Esther A. Fadaka, Sofia Perez, Gregory C. Gray, and Kristen K. Coleman 

Abstract

We conducted a serologic study of domestic cats near the epicenter of the dairy cattle outbreaks of influenza A(H5N1) in California, USA. Three of the 12 cats sampled within 2 km of farms had neutralizing antibodies against H5N1 virus. Proximity to dairy farms was a statistically significant risk factor for seropositivity.

(SNIP)

 Although several US dairy industry–related outbreaks of H5N1 among cats have been reported, the resulting seroprevalence of H5N1 virus among domestic cats near affected dairy farms is unknown. Therefore, we performed a serosurvey of domestic cats at the epicenter of the 2024–2025 dairy cattle outbreaks in California’s Central Valley.

(SNIP)

During December 2024–March 2026, we collected 73 serum samples from indoor and outdoor cats (Figure 1) within 9.7 km (6 miles) of >1 dairy farms (mean 4.7 km [2.9 miles]). Among the 73 cats, 3 tested positive for both influenza A virus nucleoprotein antibodies and neutralizing antibodies against H5 clade 2.3.4.4b. One indoor-only and 1 outdoor feral cat had neutralizing antibody titers of 1:160, and 1 indoor-only cat had a titer of 1:640, indicating strong positivity and 100% agreement between the ELISA and microneutralization assay. All negative samples had titers of <1:20.
 
Three (25%) of the 12 cats sampled within 2 km (1.24 miles) of dairy farms were seropositive for H5N1 virus (Figure 2), yielding an overall seropositivity rate of 4.1% for all surveyed cats. Seropositive cats had a mean distance to the nearest dairy farm of 1.34 km (0.8 miles), compared with 4.83 km (3 miles) for seronegative cats (p = 0.014) (Figure 3). Average age of surveyed cats was ≈1.6 years (range ≈3 months–4.9 years); 60% were female and 40% male. Age and sex were not significantly different for seropositive and seronegative cats. Of the 73 cats surveyed, 68 (93%) were in rural areas and 5 (7%) in urban areas. All seropositive cats were in rural areas. No indoor cats were fed raw meat or dairy.

       (SNIP)

Conclusions

Avian influenza A(H5N1) clade 2.3.4.4b is an emerging threat to domestic cats and public health. We report a 25% seropositivity rate for the virus among domestic cats within 2 km (1.2 miles) of dairy farms in the epicenter of the H5N1 cattle outbreaks in California during 2024–2026. Proximity to dairy farms in counties experiencing outbreaks may be a risk factor for H5N1 spillover to indoor and outdoor domestic cats. Our research provides insight into potential H5N1 virus sources and transmission routes among domestic cats in the United States, for which data are scarce. Our results may help refine public health guidance on the prevention of avian influenza in cats and set the stage for future studies.

Although only 3 seropositive cats were identified in our study, their closer proximity to dairy farms compared with seronegative cats is an important epidemiologic finding. 

        (SNIP) 

Our study highlights a critical gap in companion animal surveillance and might be helpful to health agencies as they seek approaches to mitigating this emerging infectious disease threat. Proximity to dairy farms was a risk factor for H5N1 spillover to cats in our study. However, cattle-to-cat transmission of H5N1 virus is a relatively new phenomenon, and most cat infections reported in the literature over the past 20 years have been from bird-to-cat transmission (1). To assess the in situ risk for human-adapted reassortant influenza viruses emerging in cats, future work is needed to characterize the seroprevalence of human influenza viruses in cats and avian influenza viruses in cats near outbreaks in poultry and wild birds. Cat surveillance studies also could provide insight into nearby H5N1 outbreaks that have yet to be discovered, fully investigated, or contained.

        (Continue. . . )
 

Australia Confirms `Some Local Spread' of H5N1 - CSIRO Testing An Additional 11 Samples From SA

 

" I can advise that today the consultative committee on animal diseases, emergency animal diseases met and has agreed based on testing and sequencing by the CSRO lab that some local transmission has occurred between a number of greater crested terns that are resident in South Australia.

While there remains no evidence of any mass mortalities at this point in time, we do expect with this local transmission that there will be further detections in Australian wildlife." -  From Transcript of remarks by Agriculture Minister Julie Collins

#19,267

Overnight South Australia updated their avian flu web portal, announcing that another 11 presumed positive samples have been sent to CSIRO for confirmation and genetic testing.  

Current situation

South Australia’s first confirmed detection of H5 bird flu was in a wild migratory bird (southern giant petrel) on Wednesday, 24 June at Knights Beach at Port Elliot on the Fleurieu Peninsula.

Further confirmed detections include a giant petrel (8 July at Hardwicke Bay, Yorke Peninsula); a southern giant petrel (10 July at Emu Bay, Kangaroo Island); a northern giant petrel (10 July at Port Vincent, Yorke Peninsula); three greater crested terns (10 July at Robe, Limestone Coast; 26 July at Semaphore, metro Adelaide; and 26 July at Robe, Limestone Coast); and seven greater crested terns (28 July at Cape Jaffa, Port MacDonnell and Southend, Lower South East).

A further 11 suspected H5 bird flu detections are undergoing further confirmatory testing at the Australian Centre for Disease Preparedness in Victoria.

The strain of virus is consistent with the strain detected in the Southern Indian Ocean Sub-Antarctic Territories, including Heard Island.

This strain has not been detected in poultry and has not become established in any part of Australia.

Up-to-date national information is available at birdflu.gov.au .

This comes just 1 day after CSIRO confirmed 7 new cases in local seabirds from the state's southeast Limestone Coast.  The results of those tests also strongly suggest local transmission of the virus has occurred among native birds. 

Although disappointing, none of this is particularly surprising. 

The history with HPAI H5 - particularly since the emergence and subsequent evolution of the 2.3.4.4x clade - has been that it travels well in migratory birds, and that when it reaches new territories, it often finds suitable native hosts.

While the situation in Australia continues to evolve, so far there are no reports of spillovers into poultry. 

On Monday I shared an X/Twitter post by Professor Raina Macintyre showing the recent H5N1 detections overlaid on a map of Australia's poultry production regions.

Yesterday, the above mentioned data was published in a preprint on bioRxiv.

HPAI H5N1 risk in Australia: a model for the prediction of poultry outbreaks
Pan Zhang, Samsung Lim, Ashley Quigley, C Raina MacIntyre
doi: https://doi.org/10.64898/2026.07.27.740638
This article is a preprint and has not been certified by peer review  

Preview PDF

Abstract

The panzootic highly pathogenic avian influenza (HPAI) H5N1 virus has now been detected on the Australian mainland, with incursions from the sub-Antarctic region posing an increasing threat to domestic wildlife and poultry populations. Our study aimed to predict the risk of HPAI H5N1 poultry outbreaks across Australia at the local government area (LGA) level using a range of influential risk factors.

We first used a Maximum Entropy (MaxEnt) model to estimate the environmental suitability for HPAI H5N1 occurrence across Australia. The resulting suitability layer was then integrated with five additional predictor layers, including abundance data for two Southern Ocean wild birds, one of which has introduced HPAI H5N1 into Australia; abundance data for 28 native Australian wild birds; native bird flyways across Australia; Australian chicken density; and poultry farm density. The six layers were aggregated and averaged to generate an HPAI H5N1 risk map for poultry outbreaks across Australian LGAs.

Although most incursions have occurred in Western Australia (WA) and South Australia (SA), we identified New South Wales (NSW) and Victoria (VIC) as having the highest predicted risk of HPAI H5N1 poultry outbreaks. Additional high-risk areas were identified in WA, SA, and Tasmania (TAS).

In contrast, the Northern Territory (NT) and large parts of Queensland (QLD), WA, and SA were predicted to be at low risk. These findings provide a spatially explicit framework to support targeted surveillance, preparedness, and biosecurity measures aimed at mitigating the impact of future HPAI H5N1 outbreaks in Australian poultry.

The Australian government has provided a number of resources for both commercial and backyard poultry producers to help improve their biosecurity: 

Biosecurity manuals

• National Farm Biosecurity Manual - Poultry Production
• National Water Biosecurity Manual - Poultry Production
• Chickens – Farm Biosecurity

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• Learn how to protect your backyard poultry and pet birds