The bird flu emergency is officially over, according to the U.S. Centers for Disease Control and Prevention (CDC). The agency’s emergency response to H5N1 bird flu, which was activated on April 4, 2024 —as "deactivated" on July 2, the agency told Reuters, due to declining animal infections and an absence of human cases since February.
As of July 7, the CDC will combine its bird flu updates with its routine influenza updates, according to a news release on its website. Data on the number of people who are monitored and tested for bird flu will now be reported on a monthly basis.
The CDC will also stop reporting on highly pathogenic avian influenza (HPAI) in animals, such as cows. That information will now be posted to the U.S. Department of Agriculture (USDA) website. "There is no known person-to-person spread at this time," the CDC website states. "The current public health risk is low." There have been a total of 70 human cases of bird flu and one death nationally.
"I am still concerned about H5N1 spread within poultry and on into other species," Dr. Marc Siegel, Fox News senior medical analyst, told Fox News Digital. "The dip this time of year has to do with the patten of migratory birds, where they aren't traveling, but I expect the numbers to surge back up in the fall."
Cambodia has reported three new bird flu cases in as many days, amid a spike in infections among humans in June. On Tuesday, the Ministry of Health said a 36-year-old woman in Siem Reap province – a region in the country’s northeast, which is home to the Unesco World Heritage site Angkor Wat – is in intensive care after contracting H5N1.
The case is the latest in a string of new infections in the last 10 days. On Saturday, the government said that a woman and her 16-year-old son were being treated with the antiviral tamiflu after testing positive for H5N1 in a contact tracing exercise. A week prior, their 41-year-old neighbour was in a critical condition after contracting the disease.
The latest case, the 36-year-old, lived in a village less than two miles away from this cluster of three patients. But all four had clear links to sick or dead birds, according to those investigating the incidents. A fifth case, a 52-year-old man, was announced dead at the start of last week in Svay Rieng province – a region some 250 miles away, close to Vietnam.
“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”.
In Cambodia, it is common for households to keep small flocks of chickens and ducks which roam around their homes, and live bird markets are still an important cornerstone of the food system. While culturally and economically critical, this means people live and work in the vicinity of poultry – creating a constant spillover risk. But although bird flu is now considered entrenched in poultry in the southeast Asian country, virologists and epidemiologists are racing to understand why there has been a recent spike in spillovers to humans.
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. He added that while four of the cases in June were found in Siem Reap, the other three were dotted across the small nation, which is home to roughly 17 million people.
“[This] again points toward multiple, independent spillover events rather than any linked chain of transmission.”
Dr Sovann said the Ministry of Health is concerned and will remain vigilant, because the “positive rate is high in the wild birds”, and that they’re spreading the virus to backyard poultry. But he added that the country has boosted its surveillance system, procured extra lab supplies and bird flu medicines, and strengthened capacity in private and public hospitals.
“We also encourage clinicians to send more samples, and we work together with our local researchers and hospitals to ensure we can collect all the information,” Dr Sovann said. He also noted that there is significant “cross border” trade of poultry with neighbouring countries. While the virus has been detected in birds across southeast Asia, only Cambodia and Vietnam have recently reported cases in people. “I will say that we have a good surveillance system,” said Dr Sovann. “That’s why we can detect more and more cases.”
A Washington state resident has become the first person in the world to die from a strain of a virus that has never been seen before in humans. The patient, an older adult with underlying conditions, was hospitalized with bird flu earlier this month after suffering from a high fever, confusion and severe breathing difficulties, officials said.
Lab tests confirmed the patient was infected with H5N5, a strain of bird flu previously detected in animals but never before recorded in people.
The person who died from the virus had a backyard flock of mixed domestic birds. They were first treated by doctors in Grays Harbor County, about 100 miles west of Seattle, before being transferred to an unnamed hospital in King County in the Seattle area, for specialist care. Before dying they were described as being 'severely ill'.
'The risk to the public remains low. No other people involved have tested positive for avian influenza,' the Washington State Department of Health said in a statement. Public health officials will continue to monitor anyone who was in close contact with the patient for symptoms to ensure that human-to-human spread has not occurred. There is no evidence of transmission of this virus between people.'
Further details about the patient, including their name, gender, age, and treatment, were not revealed. It was not clear how the individual was infected, but officials said it was likely linked to exposure to wild or domestic birds. Avian influenza was detected in the patient's backyard poultry flock, making it the likely cause of the infection. Two of the birds in their flock died from an unidentified illness a few weeks ago, although the rest of the birds currently remain healthy.
Officials have followed up with individuals who had contact with the patient and tested those who had symptoms. There were no further cases of bird flu detected as of Friday, officials said. It is possible to become infected with the virus after being exposed to saliva or droppings from infected birds or handling the body of a bird that died from the virus. Where the strain could be determined, all previous human cases have been infected with the H5N1 strain.
Experts said the appearance of this strain in humans showed the virus's 'unpredictable' evolution. There is currently no evidence, however, that this strain is more infectious or severe in humans than other strains of the virus.
Researchers at Cornell University have found that live H5N1 avian flu virus can remain infectious in some raw milk cheeses for as long as 120 days, roughly four months. The work took place in New York and included both lab-made cheeses and cheeses from a dairy herd that included infected cows. Lead scientist Diego G. Diel of Cornell University College of Veterinary Medicine tracked the virus through production and aging of cheese.
The team tested the virus in both controlled lab experiments and in cheddar cheese made by a company using intentionally contaminated milk. Survival of the viral particles depended on acidity and timing. The virus endured when milk was less acidic at the start of cheesemaking.
The milk’s pH set the tone for what happened next. At pH 6.6 and 5.8, the virus stayed alive during processing and through the cheese aging time (up to 120 days). However, an increase in acidity to pH 5.0, just before processing commenced, rendered the virus unable to survive. That pattern fits what is known about the avian flu virus’s outer proteins – they lose function after strong acid exposure. Independent research showed that standard heat steps in milk production removed infectivity quickly at higher temperatures than routine aging ever reaches. But when raw (unheated) milk is used, the avian flu virus is able to survive.
Cheese blocks that were made before the outbreak was discovered were already positive for live virus when they arrived at the lab. The pH of those blocks stayed near 5.3 during early aging and moisture available to microbes declined slowly without eliminating infectivity. The lab mini-cheese model and the farm products lined up on that point, which strengthens confidence in the basic finding. Measurements of live avian flu virus in the farm cheeses were confirmed by two different assays that detect viral growth.
Ferrets that drank spiked raw milk became ill, with fever and viral shedding that matched what veterinarians expect in this animal model. By contrast, ferrets that ate contaminated cheese did not become infected. This result suggests that an infectious dose is harder to reach in solids. The difference may reflect how liquids spread in the mouth and throat compared with small, swallowed pieces of food. It also highlights that matrix and behavior matter for risk, even when the same microbe is involved.
Since 2022, the highly pathogenic H5N1 virus has spread beyond birds to mammals in over 20 countries. In 2024, U.S. dairy herds joined that list, revealing new ways the virus can circulate through agricultural systems. Milk from infected cows carries high viral loads. Furthermore, contamination risks can extend across milking, transport, and storage chains before milk ever becomes cheese.
This crossover raises new biosecurity challenges for farms and regulators. The virus’s ability to persist in cold, protein-rich environments complicates standard cleaning and testing routines. Understanding how temperature, acidity, and handling shape viral survival helps public health agencies develop stronger food safety strategies for both local and international markets.
Federal regulation permits raw milk cheeses if they are cured for at least 60 days at 35 degrees Fahrenheit (1.7 degrees Centigrade), or warmer. In this work, live H5N1 virus persisted past that point, so time alone did not provide a safety margin. “The current regulation requiring 60-day aging of raw-milk cheese before marketing proves insufficient to achieve HPAI H5N1 virus inactivation and guarantee cheese safety,” stated Diel. “Therefore, implementing additional mitigation steps, such as testing of raw-milk bulk tanks or using milk pasteurization, thermization or acidification before cheese making, becomes crucial to ensure food safety,” he added.
California issued a raw milk recall after virus detection, a notice that urged people not to drink the affected lot. A federal analysis estimated that 4.4 percent of U.S. adults reported drinking raw milk at least once in the previous year, with 1.6 percent doing so frequently. Public health guidance says the risk to the general public remains low, but that assumes people avoid exposures that are easy to control.
For consumers, pasteurized milk and cheeses are the safer choice. Pasteurization involves heat treatment that kills microbes, thus protecting against many unrelated pathogens. For artisans who work with raw milk by choice or law, thermization is a practical option. This uses a gentler heat step that takes milk to just below pasteurization temperatures. Testing bulk tanks can flag problems before production starts, and suppliers can hold suspect lots until results are back.
Early milk acidification – the quick pH drop before curd sets – is another practical addition. Those steps fit into existing workflows without changing styles, and often keep products on shelves for longer. The minimum infectious dose for people in dairy matrices is still unknown, and dose response likely depends on product texture and how it is eaten.
Future studies will need to map the points where acidity, salt, moisture, and time intersect to shut down the avian flu virus more reliably. Producers and regulators can set practical targets for pre-curd acidification, salt, and hold times, then validate them with challenge studies in real facilities. That work will help align craft traditions with food safety goals.
