Cambodia - H5N1 cases 8,9,10,11, 12 (5 cases) - June 24 thru July 3, 2025

[Michael Coston]

Cambodia Reports 2 More Human H5N1 Cases for 2025



#18,774

According to my count, the latest update from the ECDC, and FluTracker's list, Cambodia has reported (prior to today) 7 human H5N1 cases, and 5 deaths in 2025.

Today they report 2 more cases from the same village as last week's case, which they describe as cases #9 & #10. Whether this is a misprint, or there is another case as yet unannounced, remains to be seen.

In any event, these two new cases were neighbors of last week's case, and are both reportedly in stable condition. Both families reportedly had contact with sick or dying chickens.

Unlike the milder 2.3.4.4b clade seen in the United States, Europe, and much of the rest of the world, recent cases from Cambodia and Vietnam have
stemmed from a resurgent older, and more virulent, clade (formerly clade 2.3.2.1c but recently redubbed as 2.3.2.1e).

The announcement (see screen shot below) was made overnight on the Cambodian MOH Facebook page. I've provided a translation (emphasis mine).

(Translation)

Kingdom of Cambodia

Ministry of Health

Press Release

2 more cases of bird flu

The Ministry of Health of the Kingdom of Cambodia would like to inform the public that, following an active investigation to find suspected cases and contacts in Lek village, Daun Keo commune, Puok district, Siem Reap province, the village where the 41-year-old woman tested positive for bird flu, which was reported on June 23, 2025, two more cases of bird flu were found, in a 46-year-old woman and a 16-year-old boy, who were mother and child and were confirmed to be positive for the H5N1 bird flu virus by the National Institute of Public Health. These are the 9th and 10th cases for 2025.

The two cases live approximately 20 meters away from the 41-year-old patient’s home. Currently, the health status of both patients is stable and they are being treated with Tamiflu with continued close monitoring. Investigations revealed that there were sick and dead chickens in the patient’s home, the neighbor’s home, and in the village. The patient had handled and touched sick and dead chickens and cooked them.

The emergency response teams of the national and sub-national ministries of health have been collaborating with the provincial agriculture departments and local authorities at all levels to actively investigate the outbreak of bird flu and respond according to technical methods and protocols, find sources of transmission in both animals and humans, and search for suspected cases and contacts to prevent further transmission in the community. They have also distributed Tamiflu to close contacts and conducted health education campaigns among residents in the affected villages.

The Ministry of Health would like to remind all citizens to always pay attention to and be vigilant about bird flu because H5N1 bird flu continues to threaten the health of our citizens. We would also like to inform you that if you have a fever, cough, sputum discharge, or difficulty breathing and have a history of contact with sick or dead chickens or ducks within 14 days before the start of the symptoms, do not go to gatherings or crowded places and seek consultation and treatment at the nearest health center or hospital immediately. Avoid delaying this, which puts you at high risk of eventual death.

(Continue . . . )


Although Cambodia continues to do an admirable job of reporting hospitalized cases, it is entirely possible that some milder infections are going unreported. Severe or critical cases are far more likely to be hospitalized, tested, and confirmed as H5N1 positive.

While we are understandably focused on H5N1 clade 2.3.4.4b - clade 2.3.2.1e in Cambodia, the recently imported (ex India) clade 2.3.2.1a case in Australia, and > 90 H5N6 cases in China - remind us that HPAI H5 continues to evolve along multiple concurrent pathways.

https://afludiary.blogspot.com/2025/06/cambodia-reports-2-more-human-h5n1.html

[sharon sanders]

Please see:

H5N1 Avian Flu: FluTrackers 2016 - Current Global Case List

Cambodia records 7th human case of H5N1 bird flu in 2025 - June 24, 2025

Cambodia - High pathogenicity avian influenza viruses (poultry) (Inf. with) - 2025 (WOAH reports)

[Pathfinder]

Puok District


/https://en.wikipedia.org/wiki/Puok_District
-------------------------------------------------------
Translation Google

Nearly 6 months into 2025, 10 cases of H5N1 bird flu have been detected

National news
Published:
30 June 2025 | 09:02

Reporter:
Park Siangli

Phnom Penh Post - Ten cases of H5N1 bird flu have been detected in nearly 6 months of 2025, of which the last two cases were a mother and child in Siem Reap Province.

The Ministry of Health said on Sunday, June 29, that two more cases of bird flu have been detected in the same area as a 41-year-old woman who the National Institute of Public Health confirmed tested positive for the H5N1 bird flu virus last Monday.

Active investigation to find suspected cases and contacts in Lwek village, Daun Kaeo commune, Puok district, Siem Reap province, the village where the 41-year-old woman tested positive for bird flu, has found two more cases of bird flu. The two cases are a 46-year-old woman and a 16-year-old boy, who are a mother and child.

The National Institute of Public Health has confirmed these two cases of H5N1 bird flu. These are the 9th and 10th cases for 2025.

The ministry stated: "The two cases resided approximately 20 meters from the home of the 41-year-old patient. The current health condition of the two patients is stable and they are being treated with the drug Tamiflu with continued careful monitoring."

The investigation revealed that there were sick and dead chickens in the patient's home, neighbors' homes, and in the village, and the patient had handled and touched the sick and dead chickens and then used them to cook and eat.

The emergency response team of the national and sub-national Ministry of Health has been collaborating with the provincial agriculture department and local authorities at all levels to actively investigate the outbreak of bird flu. In addition, they are responding according to technical methods and protocols, searching for sources of transmission in both animals and humans, and searching for suspected cases and contacts to prevent further transmission in the community, as well as distributing Tamiflu to close contacts and conducting health education campaigns among residents in the village.

The 41-year-old woman, the first H5N1 bird flu patient in the village, had handled and handled sick and dead chickens at her home and at a neighbor's house, and had cooked them for five days before she became ill.

The Ministry of Health has once again reminded all citizens to always pay attention to and be vigilant about bird flu, because H5N1 bird flu continues to threaten the health of Cambodian citizens. In case of fever, cough, sputum discharge, or difficulty breathing, and a history of contact with sick or dead chickens in the 14 days before the onset of symptoms, do not go to gatherings or crowded places and seek consultation and treatment at the nearest health center or hospital immediately, avoiding delay, which puts you at high risk of eventual death.

On June 27, officials from the Provincial Production and Veterinary Office of the Siem Reap Province Department of Agriculture collaborated with a team from the National Institute of Animal Health and Production Research (NAHPRI) to implement veterinary measures at a place where there were sick chickens in Chambok Hare village, Puok commune, Puok district.

Officials also destroyed 45 eggs and 16 chickens and sprayed the cages and the chicken coop area with disinfectant. In addition, two additional whole chickens were also sampled.

https://www.postkhmer.com/national/2025-6-30-931-262488

[Michael Coston]

Tuesday, July 01, 2025

Cambodia Reports 4th H5N1 Infection In Siem Reap Province In Last 7 Days






#18,777

A week ago, we learned of a 41 year-old woman in critical condition with H5N1 from a small village in Siem Reap Province in Northern Cambodia. There were reportedly sick and dying chickens in her village.

Two days ago, Cambodia Reported 2 More Human H5N1 Cases; both next door neighbors of the index case.

This morning the Cambodian MOH is reporting a 4th case - also in Siem Reap Province - but this time about 3 km distant from the previous 3 cases. Once again, this patient reportedly had contact with sick or dead chickens.

Since the MOH lists this as the 11th case of 2025, there appears to be at least one case we are missing. Earlier this month details on a case from last May were belatedly released, and so it is possible that information on this case is still in the pipeline.

I've posted the screenshot from the Cambodia MOH Facebook page, followed by a translation. I'll have more after the break.

Kingdom of Cambodia

Nation Religion King

Ministry of Health

Press Release

Bird flu case in 36-year-old woman

The Ministry of Health of the Kingdom of Cambodia would like to inform the public: There is another case of bird flu in a 36-year-old woman who was confirmed positive for the H5N1 avian influenza virus by the Pasteur Institute of Cambodia on June 30, 2025. The patient lives in Daun Keo village, Daun Keo commune, Puok district, Siem Reap province and has symptoms of fever, cough, shortness of breath and difficulty breathing.

This is the 11th case for 2025 in the Kingdom of Cambodia and the 4th case in Siem Reap province (living in a different village, approximately three kilometers away from the previous 3 cases of bird flu). The patient is currently under intensive medical care. Investigations revealed that the patient had a sick and dead chicken at home, which the patient had handled and touched directly, and then buried it.

The emergency response teams of the national and sub-national ministries of health have been collaborating with the provincial agriculture departments and local authorities at all levels to actively investigate the outbreak of bird flu and respond according to technical methods and protocols, find sources of transmission in both animals and humans, and search for suspected cases and contacts to prevent further transmission in the community. They have also distributed Tamiflu to close contacts and conducted health education campaigns among residents in the affected villages.

The Ministry of Health would like to remind all citizens to always pay attention to and be vigilant about bird flu because H5N1 bird flu continues to threaten the health of our citizens. We would also like to inform you that if you have a fever, cough, sputum discharge, or difficulty breathing and have a history of contact with sick or dead chickens or ducks within 14 days before the start of the symptoms, do not go to gatherings or crowded places and seek consultation and treatment at the nearest health center or hospital immediately. Avoid delaying this, which puts you at high risk of eventual death.

How it is transmitted: H5N1 bird flu is a type of flu that is usually spread from sick birds to other birds, but it can sometimes be spread from birds to humans through close contact with sick or dead birds. Bird flu in humans is a serious illness that requires prompt hospital treatment. Although it is not easily transmitted from person to person, if it mutates, it can be contagious, just like seasonal flu.

How to prevent:

• Do not touch or eat sick or dead chickens and ducks. Wear gloves and a mask or cover your nose with a scarf before handling chickens for food. Then blanch them in boiling water before plucking their feathers.
• Adhere to hygiene practices, wash hands frequently before handling food, especially after touching animals, cleaning poultry feathers, or other objects that may be sources of contamination.
• Cook food thoroughly before eating, especially meat, poultry, and eggs. Do not eat raw or undercooked eggs, and keep raw and cooked foods separate. Clean cooking utensils properly.
• If there are many sick or dead chickens at home or in the village and they have symptoms of fever, cough, sputum discharge, or difficulty breathing, please urgently seek consultation and treatment at the nearest health center or hospital to avoid delay, which puts you at high risk of eventual death.

Therefore, the public is requested to be aware and take care of their health in the above preventive measures. The Ministry of Health will continue to provide information regarding public health issues on the Ministry of Health's official social media channels, as well as the official Facebook page of the Department of Communicable Disease Control and the website www.cdcmoh.gov.kh.

For more information, please contact the Ministry of Health's emergency hotline number 115 toll-free.

Tuesday, 6th day of the Asah month, year of the Monkey, B.E. 2569, Phnom Penh, July 1, 2025

This cluster - the first extended one we've seen in quite some time - is reminiscent of the type of bird flu activity we commonly saw between 2004-2016, particularly in places like Indonesia, Egypt, and Cambodia; large die offs of poultry, followed by community clusters of illness.

Which may be due - at least, in part - to the fact that these recent Cambodian cases appear to be due to a new reassortment of an older clade of the H5N1 virus (2.3.2.1c), recently renamed 2.3.2.1e.

While summertime outbreaks of avian flu are a bit unusual, the closer one gets to the equator, the more likely influenza is to circulate year-round. Siem Reap Province is only about 13 degrees N. Latitude.

Given the frequent contacts reported with sick or dead poultry, there is no evidence to suggest human-to-human transmission of the virus.

Nevertheless, every human infection is another opportunity for the virus to better adapt to human physiology. So we watch these cases - and clusters - with considerable interest.

Stay tuned.

https://afludiary.blogspot.com/2025/07/cambodia-reports-4th-h5n1-infection-in.html

[Pathfinder]

National July 1, 2025

Cambodia announces the discovery of another case of bird flu in a 36-year-old woman

Khmer Times

The Ministry of Health on July 1, 2025, issued a press release announcing the discovery of another case of bird flu in a 36-year-old woman in Siem Reap Province.

The Ministry states that there is another case of bird flu in a 36-year-old woman who was confirmed positive for the H5N1 avian influenza virus by the Pasteur Institute of Cambodia on June 30, 2025.

The patient lives in Daun Keo Village, Daun Keo Commune, Puok District, Siem Reap Province and has symptoms of fever, cough, shortness of breath and difficulty breathing.

This is the 11th case for 2025 in the Kingdom of Cambodia and the 4th case in Siem Reap Province (approximately three kilometers away from the previous case of bird flu).

The patient is currently undergoing intensive medical care.

Investigations revealed that the patient had a sick and dead chicken at home, which the patient had handled and touched directly, and then buried.
...

https://www.khmertimeskh.com/501710022/cambodia-announces-the-discovery-of-another-case-of-bird-flu-in-a-36-year-old-woman/

[Lance]

https://www.cidrap.umn.edu/all-news

New Mexico, Texas confirm more measles cases


News brief

Today at 4:00 p.m.
Lisa Schnirring
Topics

Measles

The New Mexico Department of Health (NMDH) today reported eight more measles cases, all from Luna County, where officials last week announced an outbreak at a detection facility in Deming. The new cases push the state’s total, some of which are linked to the large West Texas outbreak, to 94 cases.

Last week, health officials announced that five detainees at the facility had tested positive for measles. The facility houses 400 inmates and employs 100 staff. Luna County is in the southwestern corner of the state, and a week before the jail-linked illnesses were reported, the NMDH announced a positive finding in wastewater from the Deming area, hinting that there was at least one undiagnosed case.

Meanwhile, the Texas Department of State Health Services today announced three more cases since its last update on June 24, raising the total in the West Texas outbreak to 753 since January. Illnesses have been trending downward since mid-March. Outbreak-linked cases were reported from 36 counties, but now only 2—Gaines and Lamar—have ongoing transmission.

Kentucky outbreak spreads to second county


In other developments, the Kentucky Cabinet for Health and Family Services said yesterday that an outbreak reported recently in Woodford County has now spread to neighboring Fayette County. Both are located in the central part of the state. Of five cases currently reported from Kentucky, four are linked to the outbreak.


H5N1 sickens another in Cambodia


News brief

Today at 3:56 p.m.
Lisa Schnirring
Topics

Avian Influenza (Bird Flu)
Cambodia’s health ministry today reported a seventh human H5N1 avian flu case for the month of June, a 36-year-old woman from the same province as the last three cases, part of an ongoing rise in illnesses with several linked to a new reassortant.

The new confirmation lifts the country’s total to 11 cases so far this year, of which 7 were reported in June. Like the most recently reported cases, the woman is from Siem Reap province in the central part of the country, according to a health ministry Facebook announcement translated and posted by Avian Flu Diary, an infectious disease news blog.

Officials, however, said she lives in a different village than the most recent three cases, a woman and her teenaged son and their neighbor, a 41-year-old woman. The woman’s village is nearly two miles from the village where the other patients live.

The latest patient is currently receiving treatment in an intensive care unit. An investigation found that she had sick and dead chickens at her home and had touched and buried them. Similar poultry contact has been noted for most Cambodian patients, among whom the infections are often severe or fatal.

More details on yet-announced earlier case


Cambodia said 11 cases have been reported this year, but only 10 have apparently been publicly announced. A few more details surfaced today about the unannounced case, which appears to be a 19-month-old boy from Takeo province who died from his infection, according to a line list in a weekly avian flu update from Hong Kong’s Centre for Health Protection (CHP). The group said the case was reported on June 30.

Also, a weekly avian flu update from the World Health Organization (WHO) Western Pacific region office said the boy’s infection was one of two from Takeo province for the week ending June 26 and that his illness onset date was June 7.


Quick takes: Mosquito-borne illness in Europe; USDA begins reopening of southern-border livestock imports


News brief

Today at 3:52 p.m.
Lisa Schnirring
Topics

Dengue

Chikungunya

Climate Change

• The European Centre for Disease Prevention and Control (ECDC) today announced that it has launched a new series of weekly updates on mosquito-borne illnesses and has published guidance on locally acquired Aedes-borne diseases in Europe. The number of locally acquired dengue infections has been increasing over the past few years, with West Nile virus infections reported from 19 countries, which the ECDC said reflects the growing geographic spread and public health impact of the diseases. Aedes albopictus is established in 369 regions of Europe, up from 114 regions a decade ago. So far this year, France has reported six outbreaks of locally acquired chikungunya on the mainland with illness onsets in May and June, which the ECDC said is an unusually early start to the season, an example of how changing environmental conditions are leading to longer and more favorable transmission periods.
• After suspending livestock imports at the southern border in May as part of the response to the rapid northward spread of New World screwworm (NWS), the US Department of Agriculture (USDA) yesterday announced a phased reopening, following extensive collaboration between the USDA Animal and Plant Health Inspection Service (APHIS) and its counterparts in Mexico on surveillance, detection, and eradication. NWS can lead to cattle loss and sporadic infections in people. The phased reopening applies to cattle, bison, and equines and will begin in southern ports starting in Douglas, Arizona.

ALL BRIEFS

[Pathfinder]

Cambodia reports three new bird flu cases as human H5N1 infections spike

A 36-year-old woman, admitted to intensive care, is the latest in a string of new infections in the last 10 days

Sarah Newey
Global Health Security Correspondent, in Bangkok
02 July 2025 2:51pm BST
...
“Up until now, we do not have signs of human-to-human transmission,” Dr Ly Sovann, the Ministry of Health’s director of communicable disease control, told the Telegraph. “All of the cases are linked with contact with sick or dead poultry, in backyard poultry or in the community.”

He added that the close proximity of the four most recent cases instead suggests “the virus has spread into the poultry in these villages”.
...
After an eight year lull, bird flu cases jumped in people in 2023 and 2024. So far this year there have been 11 infections and six deaths – including seven cases detected in June alone.

“As for why we’re seeing this uptick now – the honest answer is: we don’t fully know yet,” said Dr Erik Karlsson, head of the virology unit and director of the World Health Organization’s H5 Reference Laboratory at Institut Pasteur du Cambodge.

“It could be due to increased virus circulation in birds, but it could also reflect deeper socio-economic pressures, climate factors affecting bird movement or immunity, improved surveillance and diagnostics, or some complex combination of all of the above.

“Possibly even [there’s] a butterfly effect – a series of small shifts aligning to create a larger impact. We’re investigating a range of possible drivers across the animal, human, and environmental interface,” he told the Telegraph.

Like Dr Sovann, he stressed that although every case is a concern, there are currently no signs that the H5N1 virus circulating in the country’s birds has evolved to spread between people.

“Our genetic sequencing shows consistency with poultry-derived viruses, with no markers suggesting adaptation for onward human spread,” he said.
...

https://www.telegraph.co.uk/global-health/science-and-disease/cambodia-new-bird-flu-cases-human-h5n1-infections/

[Michael Coston]

Cambodia MOH Reports 12th H5N1 Case of 2025






#18,781

A few minutes ago the Cambodian MOH announced their 12th case of H5N1 - and the 9th case in just over a month - this time involving a 5-year-old boy from Kampot Province who had contact with sick chickens.

I've posted the screenshot, followed by a translation.

(translation)

Kingdom of Cambodia



Nation Religion King

Ministry of Health

A case of bird flu in a 5-year-old child

The Ministry of Health of the Kingdom of Cambodia would like to inform the public: There is another case of bird flu in a 5-year-old boy who was confirmed positive for the H5N1 avian influenza virus by the National Institute of Public Health on July 3, 2025. The patient lives in Kamakor Village, Sam Lahn Commune, Angkor Chey District, Kampot Province, and has symptoms of fever, cough, shortness of breath, and difficulty breathing.

This is the 12th case for 2025 in the Kingdom of Cambodia. The patient is currently under intensive care by medical staff. According to inquiries, the patient's family has about 40 chickens, as well as 2 sick and dead chickens. The boy likes to play with the chickens every day.

The emergency response teams of the national and sub-national ministries of health have been collaborating with the provincial agriculture departments and local authorities at all levels to actively investigate the outbreak of bird flu and respond according to technical methods and protocols, find sources of transmission in both animals and humans, and search for suspected cases and contacts to prevent further transmission in the community. They have also distributed Tamiflu to close contacts and conducted health education campaigns among residents in the affected villages.

The Ministry of Health would like to remind all citizens to always pay attention to and be vigilant about bird flu because H5N1 bird flu continues to threaten the health of our citizens. We would also like to inform you that if you have a fever, cough, sputum discharge, or difficulty breathing and have a history of contact with sick or dead chickens or ducks within 14 days before the start of the symptoms, do not go to gatherings or crowded places and seek consultation and treatment at the nearest health center or hospital immediately. Avoid delaying this, which puts you at high risk of eventual death.

The elusive 11th case - which has yet to be publicly announced by the MOH - was identified two days ago thanks to the expert sleuthing of Lisa Schnirring at CIDRAP, whose article H5N1 sickens another in Cambodia reported:

. . . a 19-month-old boy from Takeo province who died from his infection, according to a line list in a weekly avian flu update from Hong Kong’s Centre for Health Protection (CHP). The group said the case was reported on June 30.

Also, a weekly avian flu update from the World Health Organization (WHO) Western Pacific region office said the boy’s infection was one of two from Takeo province for the week ending June 26 and that his illness onset date was June 7.

Reports of multiple human infections across several provinces of Cambodia all within a matter of a few weeks suggests the virus - which is reportedly a new reassortment of an older clade of the H5N1 virus recently renamed 2.3.2.1e) - is spreading rapidly through local poultry.




So far most cases report close contact with sick or dead poultry, and there is no evidence to suggest human-to-human transmission of the virus.


But every spillover into humans is another opportunity for the virus to mutate and adapt to a human host, so we'll be watching this outbreak carefully.

https://afludiary.blogspot.com/2025/07/cambodia-moh-reports-12th-h5n1-case-of.html

[sharon sanders]

Case list updated. link

2025 known cases:



Cambodia - Male, 5, in ICU, sick chicken contact, Kamakor Village, Kampot province,

Cambodia - Female, 36, in ICU, sick chicken contact, Daun Keo village Siem Reap province

Cambodia - Male, 19 months, onset June 7, died, Takeo province Death

Cambodia - Male, 16, stable, sick chicken contact, son of case below, Lek village, Siem Reap province

Cambodia - Female, 46, stable, sick chicken contact, mother of case above, Lek village, Siem Reap province

Cambodia - Female, 41, critical condition, Lek village, Siem Reap province

Cambodia - Male, 52, died, dead chicken contact, Svay Rieng province Death

Cambodia - Female, 65, tested positive on May 12, under medical care, Takeo province

Cambodia - Male, 11, died, Kampong Speu province Death

Cambodia - Male, 3 years & 8 months, confirmed on March 22,Prek Ta Am village, Bos Leav commune, Chit Borei district, Kratie province, died Death

Cambodia - Male, 2 years & 7 months, died - announced February 25 Death

Cambodia - Male, 27, poultry contact, died on January 10, Kampong Cham Province Death

[Pathfinder]

• Opinion

When Hunger Overrides H5N1 Warnings: Why Cambodia’s Poor Still Eat Sick Chickens

By: Sonny Inbaraj Krishnan
June 28, 2025, 1:50 PM
...
Despite the clear and present danger, a significant disconnect persists between public health warnings and community practices, particularly in rural areas. The Cambodian Ministry of Health (MoH) issues guidelines emphasizing caution and prevention, including advice against touching or eating sick or dead chickens. However, a substantial proportion of the rural population continues to engage in high-risk behaviors, such as handling and consuming poultry that are sick or have died from illness. Case investigations by MoH’s Rapid Response Teams indicate almost all of the victims either handled sick poultry or cooked them before they became ill.

Public health messages in Cambodia are disseminated through various channels. The MoH leverages its official social media platforms, including Facebook, and its website to reach the public. Additionally, proactive efforts involve the distribution of printed campaign posters, leaflets, and stickers to key community hubs such as pagodas, schools, and individual households in high-risk provinces.

Despite extensive communication efforts, major gaps persist in how rural Cambodians understand and respond to avian influenza. A 2023 study found “very lax attitudes regarding avian flu among the rural population.” Even with general awareness of the risks, unsafe poultry-handling practices remain widespread.

Only 50 percent of participants in the study had heard advice against touching or eating sick or dying birds, and just 36.9 percent said they would follow it. Risky behaviors are common: 23 percent reported cooking sick or dead poultry for their families; another study found 53 percent did so. Many also reported touching sick birds with bare hands (75 percent) and using poultry feces as manure (77 percent). A common and dangerous misconception is that freezing sick poultry kills the virus.
...

https://www.cambodianess.com/article/when-hunger-overrides-h5n1-warnings-why-cambodias-poor-still-eat-sick-chickens

[Commonground]

[bolding is mine]
5 July 2025

Between 1 January and 1 July 2025, the World Health Organization (WHO) was notified by Cambodia’s International Health Regulations (IHR) National Focal Point (NFP) of 11 laboratory-confirmed cases of human infection with avian influenza A(H5N1) virus. Seven of the 11 cases were reported in June, an unusual monthly increase. Avian influenza A(H5N1) was first detected in Cambodia, in December 2003, initially affecting wild birds. Since then, 83 cases of human infection with influenza A(H5N1), including 49 deaths (case fatality ratio [CFR] of 59%), have been reported in the country. While the virus continued to circulate in avian species, no human cases were reported between 2014 and 2022, after which, the virus re-emerged in humans in February 2023. Since the re-emergence of human A(H5N1) infections in Cambodia in 2023, a total of 27 cases have been reported (six in 2023, 10 in 2024, and 11 to date in 2025), of which 12 were fatal (CFR 44%). Seventeen of the cases occurred in children under 18 years old. Avian influenza A(H5N1) is circulating in wild birds, poultry and some mammals around the world, and occasional human infections following exposure to infected animals or contaminated environments are expected to occur. In cases detected in Cambodia, exposure to sick poultry, often poultry kept in backyards, has been reported. According to the IHR, a human infection caused by a novel influenza A virus subtype is an event that has the potential for high public health impact and must be notified to the WHO. Based on currently available information, WHO assesses the current risk to the general population posed by this virus as low. For those occupationally exposed to the virus, such as farm workers, the risk is low to moderate, depending on the measures in place. WHO routinely reassesses this risk to factor in new information.

Description of the situation
Between 1 January and 1 July 2025, the National IHR Focal Point (NFP) of the Kingdom of Cambodia notified WHO of 11 laboratory-confirmed case of human infection with avian influenza A(H5N1) virus (clade 2.3.2.1e- formerly classified as 2.3.2.1c; from cases where virus sequences are available to date) including six deaths [CFR: 54%]. These cases are reported from the provinces of Siem Reap (4), Takeo (2), Kampong Cham (1), Kampong Speu (1), Kratie (1), Prey Veng (1), Svay Rieng (1). Of the total cases reported in 2025, seven cases were reported in June 2025.


Males account for 63% of the cases. Of the 11 cases, three cases were reported in less than five-year-olds, two cases were between the age of 5 and 18 years and six cases were reported in the age group 18-65 years. All cases had exposure – handling or culling - of sick poultry, often kept in backyards.


Avian influenza A(H5N1) was detected for the first time in Cambodia in December 2003, initially affecting wild birds. Between 2014 and 2022, there were no reports of human infection with A(H5N1) viruses. However, the re-emergence of human infections with A(H5N1) viruses in Cambodia was reported in February 2023. Since this re-emergence, Cambodia has reported 27 cases of laboratory confirmed human infection with avian influenza A(H5N1) including 12 fatalities (CFR 44%). The cases have been reported from eight provinces: Kampong Cham (1), Kampong Speu (1), Kampot (3), Kratie (3), Prey Veng (6), Svay Rieng (4), Siem Reap (5), Takeo (4).

Figure 1: Epicurve of Avian Influenza A (H5N1) cases reported in Cambodia by year from 2003- 1 July 2025



Figure 2: Geographic distribution of Avian Influenza A (H5N1) cases reported in Cambodia from 1 January – 1 July 2025.





Table 1: Details of Avian Influenza A (H5N1) cases reported in Cambodia between 1 January- 1 July 2025

Epidemiology
Animal influenza viruses typically circulate within animal populations, but some have the potential to infect humans. Human infections are predominantly acquired through direct contact with infected animals or exposure to contaminated environments. Based on the original host species, influenza A viruses can be categorized such as avian influenza, swine influenza, and other animal-origin influenza subtypes.

Human infection with avian influenza viruses may result in a spectrum of illness, ranging from mild upper respiratory tract symptoms to severe, life-threatening conditions. Clinical manifestations include conjunctivitis, respiratory, gastrointestinal symptoms, encephalitis (brain swelling), and encephalopathy (brain damage). In some cases, asymptomatic infections with the A(H5N1) virus have been reported in individuals with known exposure to infected animals and environments.

A definitive diagnosis of human avian influenza infection requires laboratory confirmation. WHO regularly updates its technical guidance on the detection of zoonotic influenza, utilizing molecular diagnostic methods such as RT-PCR. Clinical evidence indicates that certain antiviral agents, particularly neuraminidase inhibitors (e.g., oseltamivir, zanamivir), have been shown to shorten the duration of viral replication and improve patient outcomes in some cases. This antiviral agent should be administered within 48 hours of symptom onset.

From 2003 to 1 July 2025, 986 cases of human infections with avian influenza A(H5N1), including 473 deaths (CFR 48%), have been reported to WHO from 25 countries. Almost all of these cases have been linked to close contact with infected live or dead birds, or contaminated environments. From 2003 to the present, 83 cases of human infection with influenza A(H5N1), including 49 deaths (case fatality ratio [CFR] of 59%), have been reported in Cambodia.

Public health response
The Ministry of Health's national and sub-national rapid response teams have deployed to conduct further investigations and respond to the outbreak. This is being implemented in coordination with the local authorities, the Ministry of Environment and the Ministry of Agriculture, Forestry, and Fisheries.

• Investigations have focussed on identifying the source of transmission in both humans and animals, conducting enhanced surveillance, detecting suspected cases, and preventing community transmission;
• Close contacts were monitored for their health status;
• Health education campaigns were conducted for affected villages.

Animal Health:
The investigation and response team from the General Directorate of Animal Health and Production (GDAHP) and the sub-national animal health team conducted outbreak investigation and response to poultry outbreaks, in coordination with Ministry of Health, provincial health departments and local authorities.

• Investigation on and response to the poultry outbreaks, with the response interventions focusing on disinfection and limiting animal movement across villages;
• Community awareness and health education to affected communities;
• Surveillance and monitoring on poultry diseases in affected villages.

WHO risk assessment
From 2003 to 1 July 2025, a total of 986 human cases of infection of influenza A(H5N1) have been reported globally to WHO from 25 countries, including this case. Almost all of these have been linked to close contact with A(H5N1) infected live or dead birds or mammals, or contaminated environments. Human infection can cause severe disease with a high mortality rate: of the 986 infections reported globally, there have been 473 deaths (CFR 48%).

In this event, cases have been reported from seven provinces in 2025. All cases have reported direct exposure to sick/dead poultry. While human-to-human transmission cannot be ruled out, the more likely source of exposure of these cases is infected poultry of contaminated environment.

Based on information available at this time, the overall public health risk from currently known influenza viruses circulating at the human-animal interface has not changed and remains low. For those occupationally exposed to the virus, such as farm workers, the risk is low to moderate, depending on the measures in place. Additional cases in persons with exposure to sick/dead poultry is to be expected. The occurrence of sustained human-to-human transmission in this event based on currently available information is currently considered unlikely. This can, however, change and the risk assessment will be reviewed as needed if additional information becomes available.

Close analysis of the epidemiological situation, further characterization of the most recent influenza A(H5N1) viruses in both human and animal populations, and serological investigations are critical to update associated risk assessments for public health and promptly adjust risk management measures.

Current seasonal influenza vaccines are unlikely to protect humans against infections with influenza A(H5N1) viruses. Vaccines against influenza A(H5) infection in humans have been developed and licensed in some countries. WHO continues to update the list of zoonotic influenza candidate vaccine viruses (CVVs), which are selected twice a year at the WHO consultation on influenza virus vaccine composition, and on an ad hoc basis as needed. The list of such CVVs is available on the WHO website, see reference below. In addition, the genetic and antigenic characterization of contemporary animal and zoonotic influenza viruses are published here.

This risk assessment will be reviewed as needed if additional information becomes available.

WHO advice
Based on available information, this event does not change WHO recommendations on public health measures and influenza surveillance.

Given the observed extent and frequency of avian influenza in poultry, wild birds and some wild and domestic mammals, the public should avoid contact with any sick or dead animals. The public should avoid contact with high-risk environments, such as live animal markets/farms and live poultry or surfaces that might be contaminated by poultry droppings. Individuals should report deceased birds and mammals or request their removal by contacting local wildlife or veterinary authorities. Eggs, poultry meat and other poultry products should be properly cooked and handled during food preparation. Handling sick or dead poultry including slaughtering, butchering, and preparing poultry for consumption, should be avoided. Additionally, maintaining good hand hygiene through frequent hand washing with soap or using alcohol-based hand sanitizer is recommended.

Any person exposed to potentially infected animal or contaminated environments and feels unwell should seek health care promptly and inform their healthcare provider of their possible exposure.

WHO does not recommend special traveler screening at points of entry or other restrictions due to the current situation of influenza viruses at the human-animal interface.

In the case of a confirmed or suspected human infection caused by a novel influenza A virus with pandemic potential, including avian influenza viruses, a thorough epidemiologic investigation of the history of animal exposure, travel, and contact tracing should be conducted even while awaiting the confirmatory laboratory results. The epidemiologic investigation should also include early identification of unusual events that could signal person-to-person transmission of the novel virus. Clinical samples collected from confirmed or suspected cases should be tested and sent to a WHO collaborating centre (WHOCC) for further characterization. Additional samples should be collected from animals, the environment or any foods suspected to be sources of infection. 

State Parties to the International Health Regulations (2005) are required to immediately notify WHO of any laboratory-confirmed case of a recent human infection caused by a new subtype of influenza virus. Evidence of illness is not required for this notification. WHO has updated the influenza A(H5) confirmed case definition on the WHO website.

Further information

• Ministry of Health Cambodia press release. 1 Julyne 2025: https://moh.gov.kh/kh/notice/detail/183
• World Health Organization Global influenza programme, human-animal interface:  https://www.who.int/teams/global-inf...vian-influenza
• World Health Organization Monthly Risk Assessment Summary:  Influenza at the human-animal interface:  https://www.who.int/teams/global-inf...ssment-summary    
• World Health Organization Avian Influenza Weekly Update: https://www.who.int/westernpacific/e...vian-influenza
• Protocol to investigate non-seasonal influenza and other emerging acute respiratory diseases: https://www.who.int/publications-det...IHM-GIP-2018.2
• Surveillance for human infections with avian influenza A(H5) viruses: objectives, case definitions, testing and reporting: https://www.who.int/publications/i/item/B09337
• Public health resource pack for countries experiencing outbreaks of influenza in animals: revised guidance: https://www.who.int/publications/i/item/9789240076884
• Implementing the integrated sentinel surveillance of influenza and other respiratory viruses of epidemic and pandemic potential by the Global Influenza Surveillance and Response System:

• https://www.who.int/publications/i/item/9789240101432
• Case definitions for the four diseases requiring notification in all circumstances under the International Health Regulations (2005):  https://www.who.int/publications/m/i...the-ihr-(2005)
• Evidence-based risk management along the livestock production and market chain: Cambodia: https://www.fao.org/publications/card/en/c/CA7319EN/
• Disease Outbreak News. 2 September 2024:  https://www.who.int/emergencies/dise...em/2024-DON533
• Food and Agriculture Organization of the United Nations (FAO). Animal Production and Health Division (NSAH): https://www.fao.org/agriculture/anim...-and-health/en
• World Animal Health Organisation (WOAH). World Animal Health Information System (WAHIS). https://wahis.woah.org/#/in-review/5...-dashboard-url

Citable reference: World Health Organization (5 July 2025). Disease Outbreak News; Avian Influenza A (H5N1) in Cambodia Available at: https://www.who.int/emergencies/dise...em/2024-DON575

https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON575

[Pathfinder]

UN GENEVA PRESS BRIEFING

8 July 2025
...
Update on Avian Influenza in Cambodia

Shagun Khare for the World Health Organization (WHO) said that this year, Cambodia had reported 12 human cases of avian influenza - or bird flu - H5N1 infection to WHO. There was one new case reported yesterday. Eight of these cases had been reported since June. While this was a marked increase, based on available information, all these cases involved exposure to sick poultry or contaminated environments. WHO continued to assess the risk to the general public to be low, and low to moderate for people like farm workers, who were exposed to the virus through their work.

WHO was supporting Cambodia in responding to this outbreak. In addition, it routinely monitored the risk these viruses posed and published a monthly assessment of zoonotic influenza viruses, and also conducted in-depth assessments of the pandemic risk of these viruses. WHO was working with the Food and Agriculture Organization (FAO) and the World Organisation for Animal Health (WOAH) to conduct a joint risk assessment.
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https://www.unognewsroom.org/story/en/2713/un-geneva-press-briefing-08-july-2025