Virus World

The USDA tested 30 samples from states with herds infected by H5N1. Tests of ground beef purchased at retail stores have been negative for bird flu so far, the U.S. Department of Agriculture announced Wednesday, after studying meat samples collected from states with herds infected by this year's unprecedented outbreak of the virus in cattle. The results "reaffirm that the meat supply is safe," the department said in a statement published late Wednesday after the testing was completed. Health authorities have cited the "rigorous meat inspection process" overseen by the department's Food Safety Inspection Service, or FSIS, when questioned about whether this year's outbreak in dairy cattle might also threaten meat eaters.    "FSIS inspects each animal before slaughter, and all cattle carcasses must pass inspection after slaughter and be determined to be fit to enter the human food supply," the department said. The National Veterinary Services Laboratories tested 30 samples of ground beef in total, which were purchased at retail outlets in states with dairy cattle herds that had tested positive.

To date, dairy cattle in at least nine states — Colorado, Idaho, Kansas, Michigan, New Mexico, North Carolina, Ohio, South Dakota and Texas — have tested positive for H5N1, which is often lethal to poultry and other animals, like cats, but has largely spared cattle aside from sometimes disrupting their production of milk for a few weeks.  A USDA spokesperson said the ground beef they tested came from stores in only eight of those states. Colorado was only confirmed to have H5N1 in a dairy cow after USDA had collected the samples. The spokesperson did not comment on whether beef from stores in additional states would be sampled. More results from the department related to bird flu in beef are expected soon. Samples collected from the beef muscle of dairy cows condemned by inspectors at slaughter facilities are still being tested for the virus. The department is also testing how cooking beef patties to different temperatures will kill off the virus. "I want to emphasize, we are pretty sure that the meat supply is safe. We're doing this just to enhance our scientific knowledge, to make sure that we have additional data points to make that statement," Dr. Jose Emilio Esteban, USDA under secretary for food safety, told reporters Wednesday.

The studies come after the USDA ramped up testing requirements on dairy cattle moving across state lines last month in response to the outbreak.  Officials said that was in part because it had detected a mutated version of H5N1 in the lung tissue of an asymptomatic cow that had been sent to slaughter. While the cow was blocked from entering the food supply by FSIS, officials suggested the "isolated" incident raised questions about how the virus was spreading. Signs of bird flu have also made its way into the retail dairy supply, with as many as one in five samples of milk coming back positive in a nationwide Food and Drug Administration survey.  The FDA has chalked those up to harmless fragments of the virus left over after pasteurization, pointing to experiments showing that there was no live infectious virus in the samples of products like milk and sour cream that had initially tested positive. But the discovery has worried health authorities and experts that cows could be flying under the radar without symptoms, given farms are supposed to be throwing away milk from sick cows. One herd that tested positive in North Carolina remains asymptomatic and is still actively producing milk, a spokesperson for the state's Department of Agriculture and Consumer Services told CBS News.  It remains unclear how H5N1 has ended up in the milk supply. Don Prater, the FDA's top food safety official, said Wednesday that milk processors "can receive milk from hundreds of different farms, which may cross state lines," complicating efforts to trace back the virus. "This would take extensive testing to trace it that far," Bailee Woolstenhulme, a spokesperson for the Utah Department of Agriculture and Food, told CBS News.  Woolstenhulme said health authorities are only able to easily trace back milk to so-called "bulk tanks" that bottlers get. "These bulk tanks include milk from multiple dairies, so we would have to test cows from all of the dairies whose milk was in the bulk tank," Woolstenhulme said.

Testing conducted by the FDA on pasteurized commercially purchased milk has found genetic evidence of the H5N1 bird flu virus, the agency confirmed Tuesday. But the testing, done by polymerase chain reaction, or PCR, cannot distinguish between live virus or fragments of viruses that could have been killed by the pasteurization process. The agency said it has been trying to see if it could grow virus from milk found to contain evidence of H5N1, which is the gold standard test to see if there is viable virus in a product. The lengthy statement the agency released does not explicitly say FDA laboratories were unable to find live virus in the milk samples, but it does state that its belief that commercial, pasteurized milk is safe to consume has not been altered by these findings. “To date, we have seen nothing that would change our assessment that the commercial milk supply is safe,” the statement said.

The document was long on assurances but short on details of what has been undertaken or found. It does not specify how many commercial samples were taken or in how many markets, nor does it indicate what percentage of the samples were PCR-positive for H5N1. The statement did not indicate if the testing suggested the amounts of viral genetic material in the milk were low or high. Furthermore, the statement did not reveal if the milk products were purchased in parts of the country where outbreaks have occurred, or in areas where cows haven’t been seen to have been infected. The FDA did say it is testing milk from infected animals, in the processing system, and from store shelves with the goal of producing a “large representative national sample” of the milk supply. Beyond assessing the safety of the supply, such a sample could enable the agency to construct a more robust picture of H5N1’s spread among dairy cows nationally. The agency emphasized that testing of commercially available milk is ongoing, and this includes efforts to discern any potential differences between different dairy products, such as cream and whole milk....

A man in the Mekong Delta's Tien Giang Province has become the first person in Vietnam to be infected with avian flu A/H9. The 37-year-old man, who lives in Chau Thanh District, had a fever and purchased medicine to treat himself on March 10. As his conditions got serious, he was taken to the HCMC Hospital for Tropical Diseases on March 16, where doctors diagnosed him with severe viral pneumonia.A man in the Mekong Delta's Tien Giang Province tested positive with avian flu A/H9, becoming the first recorded case in Vietnam with the disease. Test results revealed that he had influenze A, and there were genetic segments similar to the A/H9 influenze strain. The Pasteur Institute of HCMC also confirmed the result.

The man is under intensive care. The man lives near a wet market that sells poultry, and there is no sick or dead animal in the areas around the patient's family. Those who have had close contact with the patient have been listed and being monitored, and they have shown no signs of respiratory infection. No outbreaks have been recorded near the patient's neighborhood. The A/H9 influenza is an avian flu infectious to people. There have been no evidence to prove that the virus can be transmitted between humans. The Ministry of Health said the man from Tien Giang is the first recorded case of A/H9 in Vietnam. From 2015 to 2023, 98 such cases have been recorded within the West Pacific region, with two deaths. There is currently no cure or vaccine for avian flu. Death rates for avian flu may reach 50%, while the rates for normal flu is at 1-4%.

This is a technical summary of an analysis of the genomic sequences of viruses associated with an outbreak of highly pathogenic avian influenza (HPAI) A(H5N1) viruses in Texas. This analysis supports the conclusion that the overall risk to the general public associated with the ongoing HPAI A(H5N1) outbreak has not changed and remains low at this time. The genome of the virus identified from the patient in Texas is publicly posted in GISAID and has been submitted to GenBank.

April 2, 2024 – CDC has sequenced the influenza virus genome identified in a specimen collected from the patient in Texas who was confirmed to be infected with highly pathogenic avian influenza A(H5N1) [“HPAI A(H5N1)”] virus and compared these with HPAI A(H5N1) sequences from cattle, wild birds and poultry. The virus sequences are HA clade 2.3.4.4b HPAI A(H5N1) with each individual gene segment closely related to viruses detected in dairy cattle available from USDA testing in Texas. While minor changes were identified in the virus sequence from the patient specimen compared to the viral sequences from cattle, both cattle and human sequences maintain primarily avian genetic characteristics and for the most part lack changes that would make them better adapted to infect mammals.

The genome for the human isolate had one change (PB2 E627K) that is known to be associated with viral adaptation to mammalian hosts, and which has been detected before in people and other mammals infected with HPAI A(H5N1) virus and other avian influenza subtypes (e.g., H7N9), but with no evidence of onward spread among people. Viruses can undergo changes in a host as they replicate after infection. Further, there are no markers known to be associated with influenza antiviral resistance found in the virus sequences from the patient’s specimen and the virus is very closely related to two existing HPAI A(H5N1) candidate vaccine viruses that are already available to manufacturers, and which could be used to make vaccine if needed. Overall, the genetic analysis of HPAI A(H5N1) viruses in Texas supports CDC’s conclusion that the human health risk currently remains low. More details are available in this technical summary below...

U.S. regulators confirmed that sick cattle in Texas, Kansas and possibly in New Mexico contracted avian influenza. They stressed that the nation’s milk supply is safe. A highly fatal form of avian influenza, or bird flu, has been confirmed in U.S. cattle in Texas and Kansas, the Department of Agriculture announced on Monday. It is the first time that cows infected with the virus have been identified. The cows appear to have been infected by wild birds, and dead birds were reported on some farms, the agency said. The results were announced after multiple federal and state agencies began investigating reports of sick cows in Texas, Kansas and New Mexico. In several cases, the virus was detected in unpasteurized samples of milk collected from sick cows. Pasteurization should inactivate the flu virus, experts said, and officials stressed that the milk supply was safe.

“At this stage, there is no concern about the safety of the commercial milk supply or that this circumstance poses a risk to consumer health,” the agency said in a statement. Outside experts agreed. “It has only been found in milk that is grossly abnormal,” said Dr. Jim Lowe, a veterinarian and influenza researcher at the College of Veterinary Medicine at the University of Illinois at Urbana-Champaign. In those cases, the milk was described as thick and syrupy, he said, and was discarded. The agency said that dairies are required to divert or destroy milk from sick animals....

USDA report (March 25, 2024):

https://www.aphis.usda.gov/aphis/newsroom/news/sa_by_date/sa-2024/hpai-cattle 

Experts fear rapid spread of disease after sampling confirms presence of H5N1 among continent’s birds. Bird flu has been detected in Antarctica for the first time, raising fears of a mass wipe-out of the continent’s avian populations. The highly-pathogenic H5N1 strain has already killed millions of birds across the globe over the past year, and has now hit one of the most important breeding grounds on the planet. Following reports of the unexplained deaths of skuas – a scavenging bird – on Bird Island in South Georgia, the British Antarctic Survey (BAS) sent samples for testing. On Monday 23 October, the results came back as positive for H5N1. “Mortality is growing,” said Dr Norman Ratcliffe, a seabird ecologist with the British Antarctic Survey, in an interview with the Telegraph. “It’s really worrying. Bird Island is one of the most exceptional habitats – the variety and density of birds is astonishing – so it’s very concerning that it has arrived in such an important location.”

‘When it takes hold it can spread quickly’

South Georgia is home to several species of albatrosses, macaroni and gentoo penguins, and northern and southern giant petrels. Experts now fear these birds could also be hit by the disease, which is transmitted mostly through faeces or direct contact. “Some of these colonies are very dense, and when it takes hold it can spread quickly,” said Dr Ratcliffe. “You can’t really limit the movements of wild birds.” Researchers had been nervously waiting for H5N1 to be detected in Antarctica following a global surge in the disease since last autumn. 

A new study highlights both the promise and the limitations of gene editing, as a highly lethal form of avian influenza continues to spread around the world.

Highlights

Black irises have been spotted in gannets that test positive for bird flu antibodies, suggesting they are an indicator that the seabirds have survived an infection with the virus. The blue eyes of some seabirds appear to turn black after they have had a bird flu infection. The colour change, seen in northern gannets (Morus bassanus), may give scientists a new way to track the impact of the virus outbreak. Bird flu has circulated seasonally among wild and farmed birds for decades, but, since October 2021, a highly pathogenic strain of the virus has swept through wild and farmed bird populations with unusual virulence. Seabirds in Europe and the UK have been particularly hard hit, with thousands killed in the past year by the H5N1 virus, including threatened gannets, puffins and great skuas. The adult survival rate for the 150,000-strong gannet population on Bass Rock, an island off the east coast of Scotland, for example, was 42 per cent below average between 2021 and 2022. Without performing invasive tests, scientists have struggled to tell whether seabirds have suffered infections and survived or so far escaped contact with the virus. Gathering this information is crucial for better understanding how the virus is affecting wild bird populations, including assessing the survival rate and whether these birds are developing any immunity to the disease. Gannets with black or mottled black irises, rather than the standard pale blue colour, have been spotted for the first time in several colonies known to have been affected by bird flu, including in the UK, France, Germany and Canada.

Jude Lane from the RSPB, a UK conservation charity, and her colleagues took samples from 18 apparently healthy gannets with normal and black irises living on Bass Rock. Eight of the birds tested positive for bird flu antibodies and, of those, seven had black irises. The incidence of this trait could be a useful non-invasive diagnostic tool for conservationists tracking the impact of bird flu, says Lane. “To be able to look at how many birds are dying, but also how many birds are surviving, will allow us to add these details into population models to predict what populations of seabirds might look like in the future,” she says. It is unclear why the irises turn black, but Lane and her colleagues are looking into this. She also plans to study whether the change is permanent, how long the virus antibodies persist in gannets and whether the birds suffer any adverse long-term effects from infection, such as fertility or vision problems. It will also be crucial to understand whether the same changes to eye colour occur in other bird species, she adds, although the feature may be harder to spot in those with naturally darker eyes.

Research study cited available in bioRxiv (May 1, 2023):

https://doi.org/10.1101/2023.05.01.538918 

These changes were unlikely to be enough to allow the virus to spread easily among humans, and the health risk to the public remains low, experts said. A sample of avian influenza isolated from a Chilean man who fell ill last month contains two genetic mutations that are signs of adaptation to mammals, officials from the Centers for Disease Control and Prevention said on Friday. In experimental animal studies, the mutations, both of which are in what is known as the PB2 gene, have previously been shown to help the virus replicate better in mammalian cells. The risk to the public remains low, health officials said, and no additional human cases have been linked to the Chilean man, who remains hospitalized. Moreover, the sample was missing other critical genetic changes that scientists believe would be necessary for the virus, known as H5N1, to spread efficiently among humans, including mutations that would stabilize the virus and help it bind more tightly to human cells. “There are three major categories of changes we think H5 has to undergo to switch from being a bird virus to being a human virus,” said Richard J. Webby, a bird flu expert at St. Jude Children’s Research Hospital. “The sequences from the person in Chile have one of those classes of changes. But we also know that of those three sets of changes, this is the easiest one for the virus to make.” PB2 mutations have been found in other mammals infected with this version of the virus, as well as in some people infected with other versions of H5N1. The mutations most likely emerged in the Chilean patient over the course of his infection, experts said.

A dog in the Canadian province of Ontario has died of H5N1 bird flu after contact with wild birds, health officials say. It’s believed to be the first time that a dog has tested positive for the new strain of the virus. A statement from the Canadian Public Health Agency said a domestic dog in Oshawa, a city in Ontario, tested positive for avian influenza after chewing on a dead goose. The dog developed clinical signs of bird flu and died a few days later. “Both the dog and goose were tested for H5N1 highly pathogenic avian influenza (HPAI) virus, and both were positive,” said Dr. Scott Weese, the Director of the Centre for Public Health and Zoonoses at the University of Guelph. “Sequencing of the virus at the National Centre for Foreign Animal Diseases was performed and the virus from both the dog and goose were the same, and were consistent with the H5N1 strain that’s circulating in wild birds and domestic poultry,” he said. It’s believed to be the first time that a dog has been infected with the new strain of H5N1, which emerged in late 2021. In 2004, a dog in Thailand died of a previous strain of H5N1 after eating a duck which was infected with the virus. In December, a cat at a poultry farm in southern France also tested positive for the new strain of H5N1. The cat became sick and was euthanized on December 23. “Based on the current evidence in Canada, the risk to the general public remains low and current scientific evidence suggests that the risk of a human contracting avian influenza from a domestic pet is minor,” the government said in a statement. Nonetheless, pet owners have been advised to not give any raw meat from game birds or poultry to pets – such as dogs and cats – and to not let them eat or play with wild birds.

Dr. Weese called the case “concerning but not surprising” and “not a doomsday scenario.” “It’s concerning because any spillover into mammals raises concerns about continued adaptation of this virus to spread outside birds,” he said. “It’s not surprising because when you have millions of infected birds internationally, it’s inevitable that domestic and wild mammals will be exposed.” A wide range of animals in Canada have tested positive for bird flu during the past year, including foxes, seals, dolphins, black bears, wild mink, porpoises and skunks, according to the National Centre for Foreign Animal Diseases. The global spread of H5N1 clade 2.3.4.4b – and the recent spread to a growing number of mammals – has raised concern about the possibility of a future variant which could lead to human-to-human transmission. So far, only a few human cases have been found after contact with infected birds. “The global H5N1 situation is worrying given the wide spread of the virus in birds around the world and the increasing reports of cases in mammals, including in humans,” Dr. Sylvie Briand, a WHO official, said on February 24. “WHO takes the risk from this virus seriously and urges heightened vigilance from all countries.” Last week, Chile reported that more than 1,500 sea lions are believed to have died of H5N1 bird flu, which followed the deaths of at least 3,500 sea lions in neighboring Peru. Chile also reported its first human case of bird flu on March 29.

A woman in southern China has tested positive for H3N8 bird flu, local officials say, making it only the third time that the virus has been found in humans, although a previous strain may have caused the 1889 pandemic. The Guangdong Provincial Center for Disease Control and Prevention, in a brief statement released on Monday, said a 56-year-old woman from Zhongshan City had been infected with H3N8. The woman, who has multiple myeloma and other underlying health conditions, had exposure to live poultry before falling ill, the statement said. Wild birds are also frequently found near her home. Details about her condition have not been released. “No abnormalities have been found in close contacts so far,” the Guangdong CDC said. “Experts believe that this is a sporadic case and the risk of virus transmission is low at this stage.”

The news comes nearly a year after the H3N8 virus was confirmed in humans for the first time, when a 4-year-old boy in central China became seriously ill. The family’s pets – a dog and a cat – were also infected. A second person, a 5-year-old boy from Hunan province, was infected about a month later, in May 2022. He recovered quickly after only mild symptoms, according to the Chinese government. H3N8 is found in birds but also in horses and is one of the two viruses which cause dog flu. The new case in China is only the third confirmed case in humans, and the first in an adult. But while it was never found in humans until 2022, researchers have long believed that a previous strain of the virus may have caused the 1889 pandemic, which was known as “Asiatic flu” or “Russian flu.” More recent research suggests a strain of coronavirus may have caused the pandemic.

The Centers for Disease Control and Prevention and National Center for Immunization and Respiratory Diseases have provided updated results of a preliminary assessment of the H5N1 viruses identified in two human infections detected in Cambodia in 2023 based on their genetic sequences and gives an update on the epidemiological investigation. On February 26, 2023, the Institut Pasteur du Cambodge, in collaboration with the Cambodian Ministry of Health, shared the full genetic sequence of the H5N1 virus recovered from the patient who died in that country on February 22, 2023 The genetic sequence of the second case was later also shared by the Institut Pasteur du Cambodge. CDC has conducted a preliminary analysis of the genetic sequences of these H5N1 bird flu viruses. They are H5N1 viruses from clade 2.3.2.1c, which are different from the H5N1 viruses now spreading in U.S. wild birds and poultry, which are from clade 2.3.4.4b. These viruses are similar to past 2.3.2.1c viruses detected in that geographic area over recent years. The genetic sequences suggest that an existing clade 2.3.2.1c candidate vaccine virus (CVV), called NIBRG-301 (A/duck/Vietnam/NCVD-1584/2012-like) would offer protection against the viruses identified in Cambodia.

Additionally, there were no genetic changes identified that are known to be associated with increased ability to spread to people or reduce susceptibility to influenza antiviral drugs. CDC had requested virus samples from both cases in Cambodia in order to conduct additional laboratory testing/analysis to confirm these and other characteristics of the viruses and to provide a more detailed risk assessment. CDC continues to support the Ministry of Health, Ministry of Agriculture, Animal, Forestry and Fisheries, and Ministry of Environment, in its ongoing One Health investigation. Evidence to date continues to support the conclusion that these two human infections are the result of two instances of bird-to-human spread. There is still no indication of person-to-person spread associated with these two cases. The investigation has revealed that both patients became sick at about the same time and were likely exposed to sick or dead poultry prior to becoming ill, including being near sick/dead poultry kept in a coop under the house or through butchering, cleaning, and cooking chicken that died. Investigation and containment efforts continue, including monitoring and/or testing of contacts of the two cases for 10 days after their last exposure, along with active surveillance for influenza-like-illness in the village. CDC will provide additional updates as needed.

Bird flu isn’t just lurking inside cows, new research shows. Florida scientists have reported the first known case of highly pathogenic H5N1 avian influenza in a common bottlenose dolphin (Tursiops truncatus). Though the case dates back to 2022, it’s the latest indication that these flu strains can potentially infect a wide variety of mammals. The report was published Friday in the Nature journal Communications Biology. According to the paper, the flu-infected dolphin was first identified on March 29, 2022. Researchers with the University of Florida’s Marine Animal Rescue Program were notified of a dolphin that appeared to be in clear distress around the waters of Horseshoe Beach in North Florida. By the time they arrived, however, the dolphin had already died. It was subsequently packed in ice and taken to the university for an autopsy the following day. The post-mortem examination found signs of poor health and inflammation in the dolphin’s brain and meninges (the membrane layers that protect the brain and spinal cord). The dolphin tested negative for other common infectious causes of brain inflammation, which prompted the researchers to expand their search. They knew that wild birds can develop neuroinflammation from highly pathogenic strains of avian influenza, that several bird die-offs tied to the flu had occurred in the area recently, and that recent outbreaks had occurred among other populations of marine mammals elsewhere, so they decided to screen for it. Testing then revealed the presence of H5N1 within the dolphin’s lungs and brain.

There have been sightings of highly pathogenic avian influenza (HPAI) in other marine mammals lately, such as harbor seals and other species of dolphins. But this is the first reported case documented in a common bottlenose dolphin and the first report in any cetacean (dolphins and whales) within the waters of North America. Strains of bird flu are classified as highly pathogenic when they cause severe illness and deaths in wild birds, so it’s not necessarily a given that they will be as dangerous to other animals they infect. The current outbreaks of H5N1 bird flu in cows, for instance, have caused generally mild illness to date. But strains belonging to this particular lineage of H5N1 (2.3.4.4b) have been deadly to marine mammals. The strain in this case did not appear to develop known genetic changes that would make it easier to infect and transmit between mammals, the authors found. But flu viruses mutate very quickly, leaving open the possibility that some strains will adapt and pick up the right changes that can make them a much bigger threat to mammals both on land and in the sea. “Human health risk aside, the consequences of A(H5N1) viruses adapting for enhanced replication in and transmission between dolphins and other cetacea could be catastrophic for these populations,” the authors wrote. The researchers are continuing to investigate the case, hoping to pinpoint the origins of the dolphin’s infection and to better understand the potential for bird flu strains to successfully jump the species barrier to these marine mammals.

Studiy cited published in Communications Biology (April 18, 2024):

https://doi.org/10.1038/s42003-024-06173-x

We reviewed information about mammals naturally infected by highly pathogenic avian influenza A virus subtype H5N1 during 2 periods: the current panzootic (2020–2023) and previous waves of infection (2003–2019). In the current panzootic, 26 countries have reported >48 mammal species infected by H5N1 virus; in some cases, the virus has affected thousands of individual animals. The geographic area and the number of species affected by the current event are considerably larger than in previous waves of infection. The most plausible source of mammal infection in both periods appears to be close contact with infected birds, including their ingestion. Some studies, especially in the current panzootic, suggest that mammal-to-mammal transmission might be responsible for some infections; some mutations found could help this avian pathogen replicate in mammals. H5N1 virus may be changing and adapting to infect mammals. Continuous surveillance is essential to mitigate the risk for a global pandemic.

Since last century, highly pathogenic avian influenza (HPAI) viruses have caused diverse waves of infection. However, the ongoing panzootic event (2020–2023) caused by HPAI A(H5N1) virus could become one of the most important in terms of economic losses, geographic areas affected, and numbers of species and individual animals infected. This pathogen appears to be emerging in several regions of the world (e.g., South America); it has caused death in domestic and wild birds but also in mammals. This trend is of great concern because it may indicate a change in the dynamics of this pathogen (i.e., an increase in their range of hosts and the severity of the disease). H5N1 has affected several mammal species since 2003, thus raising concern because H5N1 mammalian adaptation could represent a risk not only for diverse wild mammals but also for human health.

Unfortunately, information about this topic, especially related to the current panzootic (2020–2023), is disperse and available often only in gray literature (e.g., databases and official government websites). This fact complicates access and evaluation for many stakeholders working on the front lines (e.g., wildlife managers, conservationists, and public health authorities at regional and local levels). For this article, we compiled and analyzed information from scientific literature about mammal species, including humans, naturally affected by the current panzootic event and compared those findings with the outcomes of previous waves of H5N1 infection. We focus particularly on the species infected, their habitat, phylogeny, and trophic level, and the sources of infection, virus mutations, clinical signs, and necropsy findings associated with this virus. We also address potential risks for biodiversity and human health.

Published in  Emerging Infectious Diseases (March 2024):

https://doi.org/10.3201/eid3003.231098 

The bird flu virus spreading through dairy cattle in the United States may be expanding its reach via milking equipment, the people doing the milking, or both, U.S. Department of Agriculture (USDA) representatives reported today at an international, virtual meeting held to update the situation. The avian virus may not be spreading directly from cows breathing on cows, as some researchers have speculated, according to USDA scientists who took part in the meeting, organized jointly by the World Organisation for Animal Health and the United Nations’s Food and Agricultural Organization. “We haven’t seen any true indication that the cows are actively shedding virus and exposing it directly to other animals,” said USDA’s Mark Lyons, who directs ruminant health for the agency and presented some of its data. The finding might also point to ways to protect humans. So far one worker at a dairy farm with infected cattle was found to have the virus, but no other human cases have been confirmed.

USDA researchers tested milk, nasal swabs, and blood from cows at affected dairies and only found clear signals of the virus in the milk. “Right now, we don’t have evidence that the virus is actively replicating within the body of the cow other than the udder,” Suelee Robbe Austerman of USDA’s National Veterinary Services Laboratory told the gathering. The virus might be transmitted from cow to cow in milk droplets on dairy workers’ clothing or gloves, or in the suction cups attached to the udders for milking, Lyons said. (In a 30 March interview with Sciencenone, Thijs Kuiken, a leading avian influenza researcher at Erasmus Medical Center, had suggested the milking machines might be responsible because the components may not always be disinfected between cows.)

The influenza virus causing the outbreak, an H5N1 subtype that is known as clade 2.3.4.4b, has devastated wild birds and poultry around the world for more than 2 years, and researchers at first thought migratory birds were responsible for spreading it to all of the affected dairy farms. But USDA scientists now think the movement of cattle, which are frequently transported from the southern parts of the country to the Midwest and north in the spring, may also have played an important role. And they floated the possibility, without naming specific herds or locations, that all affected cows may trace back to a single farm. Since first revealing the infection of dairy cows with this bird flu virus on 25 March, USDA has confirmed it has spread to cattle in six states. And the agency has used the virus’ genetics to track its movements. The virus found on U.S. farms has a specific genetic signature, which led USDA to name it 3.13. “It’s not a common [strain], but it’s very much a descendant of the viruses that have been dominating the flyways in the Pacific and the central flyways in the United States,” Robbe Austerman said.

The USDA scientists reported that the agency’s analysis of the different viruses from the cows indicates they likely came from one source. Cows from infected farms in Texas appear to have moved the virus to farms in Idaho, Michigan, and Ohio. “The cow viruses so far have all been similar enough that it would be consistent with a single spillover event or a couple of very closely related spillover events,” Robbe Austerman said. “So far we don’t have any evidence that this is being introduced multiple times into the cows.” The virus in cows could spread to poultry, which has that industry on edge. USDA tightly regulates avian influenza virus strains that are deadly to poultry, requiring culling of entire flocks if one bird tests positive for this H5N1 or one of its relatives; to date, commercial and backyard poultry farms have had to cull 85 million birds because of this virus. But USDA is not calling for any such drastic measures with cow herds. In response to questions from Sciencenone, Ashley Peterson, who handles regulatory affairs for the National Chicken Council, said “out of an abundance of caution, we believe it is prudent to restrict the movement of cows from positive herds.” Although some researchers agree USDA should stop the transport of dairy cows, the agency has so far declined to take that disruptive action. “We heavily rely on the producers who have been isolating the animals within the dairy herds,” Lyons said. USDA also says it has no evidence of beef cattle becoming infected. USDA and the Food and Drug Administration have stressed that pasteurization kills viruses, so there is “no concern” about the safety of commercial milk. They do recommend people not consume raw milk or products made from it.

Sources tell Science none some dairy farms that were later shown to be infected first noticed dead cats as early as mid-February. The animals, which often drink spilled milk on farms, “were the canary in the mine,” one said. The cows’ milk was also unusually thick. Those signs, coupled with the discovery of dead birds on the farms, led to the testing of cow milk for the bird flu virus and the 25 March USDA announcement. Oddly, the dead birds on infected farms were not waterfowl, the migratory birds that typically spread the avian flu viruses to poultry, but “peridomestic” species such as grackles, blackbirds, and pigeons. One farm had the virus detected in poultry before it was found in its cows, and although Robbe Austerman said she hesitated to call it the “ancestral strain,” she noted that “all of the detection so far in cattle are clustered around that.” Further studies should clarify how the virus wound up in cows, which sometimes become infected with flu viruses but have never before been shown to have one that causes high mortality in birds. One possibility is that birds infected cows by shedding their droppings in the cows’ feed or water. But bird flu viruses in the past have also spread for many kilometers in the wind, moving from one poultry farm to another. So the current H5N1 strain could have moved from waterfowl to poultry to cattle—or directly from poultry to cattle and then even to the peridomestic birds. “This could be a multifactorial presentation that we’re seeing,” Lyons said. “Lots of questions still to be answered.”

Health Alert: First Case of Novel Influenza A (H5N1) in Texas, March 2024 Health Alert April 1, 2024 Summary The Texas Department of State Health Services (DSHS) is reporting the first human case of novel avian influenza A(H5N1) in Texas. The patient became ill following contact with dairy cows presumed to be infected with avian influenza. The patient’s primary symptom was conjunctivitis. This is the second case of avian influenza A(H5N1) identified in a person in the United States and is believed to be associated with the recent detections of avian influenza A(H5N1) in dairy cows announced by the Texas Animal Health Commission. DSHS along with local, regional, state, and federal partners, is investigating this ongoing situation. Avian influenza A(H5N1) viruses have only rarely been transmitted from person to person. As such, the risk to the general public is believed to be low; however, people with close contact with affected animals suspected of having avian influenza A(H5N1) have a higher risk of infection.

DSHS is issuing this health alert to provide awareness to healthcare providers and ask them to be vigilant for people with signs and symptoms of avian influenza A(H5N1). Suspicion for avian influenza A(H5N1) should be heightened for people who have had contact with animals suspected of having avian influenza A(H5N1)...

The Minnesota Board of Animal Health (MBAH) today announced that highly pathogenic avian influenza (HPAI) has been detected in a baby goat that lived on a farm where an outbreak had recently been detected in poultry. Today’s announcement marks the first US detection in livestock. Health officials, including the US Department of Agriculture (USDA), are investigating the transmission of the virus on the farm, which is located in Stevens County in west-central Minnesota. All species on the farm have been placed under quarantine. Poultry had already been quarantined following the February outbreak. "This finding is significant because, while the spring migration is definitely a higher risk transmission period for poultry, it highlights the possibility of the virus infecting other animals on farms with multiple species, " said Minnesota state veterinarian Brian Hoefs, DVM. " Thankfully, research to-date has shown mammals appear to be dead-end hosts, which means they’re unlikely to spread HPAI further...."

Genetic changes to avian influenza viruses have led to spread among many wild species, creating an uncontrollable global outbreak. Researchers studying the evolution of the bird flu virus over the past 18 years have shown how the strain currently circulating worldwide, an extremely deadly form of the H5N1 subtype, has become increasingly infectious to wild birds. The strain emerged in Europe in 2020, and has spread to an unprecedented number of countries. The study, published in Nature on 18 October, looked at changes to the virus’s genome over time and used data on reported outbreaks to track how it spread. In 2020, the rate of spread among wild birds was three times faster than that in farmed poultry, because of mutations that allowed the virus to adapt to diverse species. “What was once very clearly a poultry pathogen has now become an animal-health issue much more broadly,” says Andy Ramey, a wildlife geneticist at the US Geological Survey Alaska Science Center in Anchorage. “That has implications for wildlife and domestic poultry as well as us humans that rely upon these resources.”

Persistent outbreaks

H5N1, classified as a highly pathogenic avian influenza (HPAI) virus because of its high death toll in poultry, was first detected in birds in China in 1996. Outbreaks are usually seasonal, synchronizing with bird migration in Northern Hemisphere autumn. But since November 2021, they have become persistent. In 2022, the virus killed millions of birds across five continents and seeded outbreaks among farmed mink and various marine mammals. To study changes in the virus’s behaviour, the authors examined data reported to the Food and Agricultural Organization of the United Nations and the World Organisation for Animal Health between 2005 and 2022, and analysed more than 10,000 viral genomes. Their work reveals that in mid-2020, a new H5N1 strain evolved from an earlier variety, called H5N8, which first emerged in poultry in Egypt between 2016 and 2017 and caused global flare-ups throughout 2020 and 2021 (see ‘Bird flu outbreaks’). The new H5N1 virus mutated through interactions with non-deadly varieties of bird flu, called low-pathogenic avian influenza (LPAI) viruses, that had been circulating among wild birds in Europe since 2019. It developed two subtypes in 2021 and 2022. One spread across the northern coastal regions of central Europe and was eventually carried to North America by birds migrating across the Atlantic Ocean. The other was carried around the Mediterranean Sea and into Africa. Many bird flu outbreaks begin in poultry, but spillover into wild birds has spread the disease into larger areas, creating a global challenge that is difficult to manage, the study found. “Once it’s adapted to wild birds, we have no mechanism to control the virus. And I think that’s the biggest impact that has changed now,” says co-author Vijaykrishna Dhanasekaran, an evolutionary biologist and virologist at the University of Hong Kong. Louise Moncla, an evolutionary virologist at the University of Pennsylvania in Philadelphia, agrees. “Regardless of how much outbreak response you do in poultry, if it’s coming in from wild birds repeatedly, this is going to be really hard to manage.” “This is really something that most of the world at this point has skin in the game,” adds Ramey.

Mixing viruses

LPAI viruses often circulate freely in poultry and wild birds. Previous infection with these non-deadly strains is thought to encourage population immunity in wild birds. “You can think of it as an imperfect vaccine, that doesn’t stop infection, but it helps mitigate the effects of disease,” says Ramey. But “there’s probably two sides of the coin here”, he adds. HPAI viruses can mutate through interactions with LPAI ones. In both, the genome is split into eight segments that can be mixed and matched. “When two viruses co-infect the same cell, they could swap their genes when the virus is getting packaged,” says Dhanasekaran. Because of this, LPAI viruses — especially a strain called H9N2 — play a major part in the evolution of H5N1, he adds. But they are not well monitored. “Eradication or elimination strategies that target these low pathogenic viruses would be a huge step forward in terms of controlling avian influenza itself,” says Dhanasekaran.

Research Cited published in Nature (Oct. 18, 2023):

 https://doi.org/10.1038/s41586-023-06631-2 

Authorities have confirmed the death  of 38 cats died in South Korea due to avian influenza. It is the first time in South Korea that cats have died from avian influenza, and it is the second time in the world. 40 cats were being protected at a private cat shelter in Seoul,. On the 24th of last month, the cats started dying due to high fever and loss of appetite. 38 cats died in one month. A research team led by Professor Song Dae-seop of the Department of Veterinary Medicine at Seoul National University investigated and confirmed that it was H5N1 avian influenza.

Of the 38 dead, 35 were incinerated and 3 were frozen. The World Health Organization warned of the dangers of avian influenza by announcing the first case of avian influenza in which 29 cats died in Poland on the 17th. The quarantine authorities said they are conducting an epidemiological investigation and are preparing quarantine measures with domestic and foreign experts.

Warning issued by European Food Safety Authority after 24 cats test positive for virus in Poland. Cats should be kept indoors to avoid catching bird flu, European health officials have told pet-owners as the continent battles its worst-ever outbreak of the virus. The warning has been issued by the European Food Safety Authority (EFSA) after 24 cats tested positive for the virus in Poland, sparking fear that avian influenza could be evolving to spread among certain mammals. Since late 2021, bird flu has killed millions of birds across Europe and beyond. Last year, 67 countries in five continents reported highly pathogenic H5N1 outbreaks, with more than 131 million domestic poultry lost due to death or culling in affected areas. But the rising number of infections in mammals – outbreaks have been reported in 26 species, including farmed mink in Spain – has generated particular concern. Calling for increased surveillance of bird flu in wild and domesticated mammals, the EFSA said on Thursday that “it is recommended to avoid exposure of domestic cats and dogs, and in general carnivore pets, to dead or diseased animals”. It added: “Possible measures are keeping dogs on a leash, and confining cats indoors in areas where extensive circulation of HPAI [highly pathogenic avian influenza] viruses in wild birds has been confirmed.”

In Poland, the deaths of around 70 domestic cats since June 23 are being investigated, according to local media reports.  At least 24 tested positive for H5N1, with the source of the infections yet to be determined. Reports have linked the outbreak to raw poultry meat contaminated with the virus. Elsewhere, five dogs and a cat have been infected with bird flu in Italy. The EFSA has also called for research to investigate the role that farmed and domesticated mammals could be playing in harbouring the bird flu virus and potentially driving its ability to spread beyond avian species. “Prompt generation and timely sharing of sequence data is highly recommended to promptly identify the emergence of variants with a possible increased ... potential” to jump into humans, the agency said. Earlier this week, the World Health Organisation (WHO) said that “some mammals may act as mixing vessels for influenza viruses, leading to the emergence of new viruses that could be more harmful to animals and humans.” In a statement released on Wednesday, it said that the recent surge in bird flu outbreaks among mammals could help the virus spread in humans. “Avian influenza viruses normally spread among birds, but the increasing number of H5N1 avian influenza detections among mammals – which are biologically closer to humans than birds are – raises concern that the virus might adapt to infect humans more easily.” In April, the virus was also found to “efficiently” spread between ferrets in a laboratory, the first study confirming that the virus can spread from mammal to mammal.

A summary of the case and the genomic analysis of the virus from the first human case of H5N1 reported in Chile. The overall risk to human health associated with the ongoing A(H5N1) outbreaks in wild birds and poultry has not changed and remain.

PARIS, April 6 (Reuters) - France has launched a tender for 80 million doses of bird flu vaccines in order to be ready to start its vaccination programme in the autumn, it said on Thursday, the first member of the European Union to start such a scheme. The announcement came after French health and safety agency ANSES earlier on Thursday endorsed the government's plan to vaccinate millions of poultry birds against bird flu, setting out three scenarios for the campaign. Avian influenza, commonly called bird flu, has killed hundreds millions of birds around the world but governments have been reluctant to roll out vaccination programmes mainly because of the trade curbs these would entail. France - the worst affected European Union country last year, when it culled more than 20 million birds - said in December it aimed to start vaccinations this autumn. The pre-order, to be confirmed if final test results are positive, is to vaccinate ducks only, a spokesperson at the French agriculture ministry said. Ducks are very receptive to the virus and remain asymptomatic for many days, increasing the risk of transmission.

France has mandated two companies, France's Ceva Animal Health and Germany's Boehringher Ingelheim to develop bird flu vaccines for ducks. Ceva said initial results were "very promising", notably by sharply reducing the excretion of the virus by infected birds. ANSES, which the ministry had tasked with presenting a range of vaccination strategies, reported back with three scenarios on Thursday. The most limited plan would involve vaccinating all breeding poultry birds, which would entail millions of doses. A second option to be applied simultaneously or at a later stage, adds foie gras ducks, free-range turkeys and ducks and future free-range layer pullets; and a third all layer hens and web-footed poultry not already covered elsewhere. None of the scenarios involves vaccinating broilers which account for the majority of France's poultry, considered at relatively low risk of catching the virus. The government tends to at least partly follow ANSES recommendations. "In view of the particularly worrying epidemiological context... the agency stresses the importance of implementing the broadest possible vaccination strategy, provided the means are available," the agency advised. ANSES also stressed the capacity for the virus to jump across species barriers, posing a potential risk to human health. Bird flu is transmitted by infected faeces from migrating wild birds or direct contact with contaminated feed, clothing and equipment, or through the air.

Reporting by Sybille de La Hamaide; editing by John Stonestreet and Susan Fenton

The government is investigating the source of contagion as well as others who were in contact with the patient. Chile has reported cases of the H5N1 bird flu since late last year. Chile detected the first case of bird flu in a human, the country’s health ministry reported on Wednesday. The case was detected in a 53-year-old man who presented severe influenza symptoms, according to a statement issued by the ministry, but they noted the patient was in stable condition. The government is also investigating the source of contagion as well as others who were in contact with the patient. Chile has reported cases of the H5N1 bird flu since late last year in wild animals. Recent cases in industrial farms caused the government to halt poultry exports. Industrial cases have also been detected in Argentina, but Brazil, the world’s largest exporter of poultry, remains free of the contagion. Chilean health authorities noted the virus can be transmitted from birds or marine mammals to humans, but there is no known human-to-human transmission. Earlier this year, Ecuador confirmed its first case of human transmission of bird flu in a nine-year-old girl. Global health officials have said risk of transmission between humans is low, but vaccine makers have been preparing bird flu shots for humans “just in case.”

Bird flu is infecting the brains of wild mammals such as foxes and raccoons and may be making them behave in unusual ways, according to a study in the US. Out of 57 live mammals found to be infected, 53 had neurological symptoms, such as seizures, problems with balance, tremors and a lack of fear of people. The risk to people appears to be low. “There isn’t yet any evidence that red foxes or other wild mammals …