Concerns swirl across the country as highly pathogenic avian influenza (HPAI) A(H5N1) viruscommonly known as avian influenza or H5 bird fluonce again takes flight. This avian influenza strain has killed millions of wild birds and caused sporadic outbreaks among poultry. Now there is a multistate outbreak among dairy cows in the U.S.
While bird flu is rare in humans, three cases have been reported in the U.S. April marked the first report of a cow-to-human case of HPAI A(H5N1) virus infection in a dairy worker in Texas. The Centers for Disease Control and Prevention (CDC) confirmed a second human case of bird flu in late May in a dairy worker in Michigan, where the virus has also been identified in dairy cows. Both patients only reported eye symptoms associated with conjunctivitis.
In a third case, another dairy worker in Michigan had eye symptoms as well as respiratory symptomscongestion, sore throat, cough, fatigue, and runny and burning eyesthataremore typical of human influenza infections.
Previously, the A(H5N1) virus was confirmed in a person in Colorado in 2022 from exposure to poultry . The patient reported fatigue as their only symptom and fully recovered.
Meanwhile, the U.S. Department of Agriculture has reported that dairy cattle herds in nine states have confirmed cases of A(H5N1) virus infections. While A(H5N1) virus causes less severe illness in cattle than in poultry, the disease remains a concern for all livestock and also for humans who come into contact with infected animals.
Here are some questions patients might have about A(H5N1) virus, along with the answers that physicians should be ready to share. Visit the AMA bird flu (H5N1) resource center to learn more.
What is the A(H5N1) virus or H5 bird flu?
HPAI A(H5N1) virus is a type of influenza virus that causes highly infectious and severe respiratory disease in birds. That is why it is called avian influenza or bird flu. It is causing outbreaks in poultry and dairy cows in the U.S. And while the current public health risk for the general public is low, the CDC is carefully watching the situation and working with states to monitor people with animal exposures.
What are the symptoms of A(H5N1) virus infection?
They range from no symptoms to mild, flu-like illness to severe illness that requires hospitalization. For example, the dairy workers infected in the U.S. reported mild illness, with the main symptoms being conjunctivitis or eye infection.
Some other common symptoms are consistent with the flu, according to the CDC, and include cough, sore throat, eye redness or discharge, fever or feeling feverish, runny nose, fatigue, muscle or joint pain and headache. For moderate to severe illness, symptoms can include shortness of breath, difficulty breathing and altered mental state or seizures.
How long after exposure do symptoms appear?
People who are exposed should monitor themselves daily for signs and symptoms of new illness for up to 10 days after the last known exposure.The incubation period depends on the strain of the virus, the dose, the route of exposure and the species. Available data suggests that the estimated incubation period for human infection with A(H5N1) virus is generally three to five days, but has been reported to be as long as seven to 10 days.
How is A(H5N1) bird flu diagnosed?
The A(H5N1) virus infection in people cannot be diagnosed by clinical signs and symptoms alone. Laboratory testing is needed to confirm A(H5N1) virus infection in humans.
Physicians and other health professionals should notify their state and local health departments to arrange testing for influenza A(H5N1) virus. They should also collect respiratory specimens from the patient to test for influenza A(H5N1) virus at the health department. If the exposed person has conjunctivitis, with or without respiratory symptoms, both a conjunctival swab and a nasopharyngeal swab should be collected for testing.
Who is at risk of contracting A(H5N1) virus?
The risk of A(H5N1) virus infection is low for the general public in the U.S. But people who work with birds, poultry or cows, or have recreational exposure to them, are at higher risk.
How is A(H5N1) virus transmitted to humans?
People rarely get A(H5N1) virus infections, but when they do, it is most often acquired through close, prolonged and unprotected contactno gloves, protective wear, face masks, respirators or eye protectionwith infected birds or other animals.
Human infections with avian influenza A viruses can happen when enough virus gets into a persons eyes, nose or mouth, or is inhaled. This can happen when the virus is in the air in droplets or dust and a person breathes it in or when a person touches something that has the virus on it and then touches their mouth, eyes or nose, according to the CDC.
What are infection prevention and control recommendations for A(H5N1)?
Standard, contact and airborne precautions are recommended for patients presenting for medical care or evaluation who have illness consistent with influenza and recent exposure to birds or other animals potentially infected with HPAI A(H5N1) virus.
If signs and symptoms compatible with avian flu are present, physicians should isolate the patient and follow infection-control recommendations, including the use of personal protective equipment.
Get trusted insight from physicians on hot topics in todays health care headlinesdelivered to your inbox.
What treatments are available for A(H5N1) virus infections?
There is Food and Drug Administration-approved antiviral treatment for seasonal flu that can be used for A(H5N1) virus infection. Antiviral treatment is recommended with oseltamivir as soon as possible for outpatients and hospitalized patients who are suspected, probable or confirmed cases of human infection with A(H5N1).
Starting empiric antiviral treatment with oral or enterically administered oseltamivirtwice daily for five daysis recommended regardless of time since onset of symptoms. Antiviral treatment should not be delayed while waiting for laboratory test results. And while there is currently no indication of the disease spreading further among humans, these patients should isolate to reduce risk of infecting others.
How effective are antiviral medications against A(H5N1) virus?
Antiviral treatment works best when started early after symptoms begin. Antivirals can also be given soon after unprotected exposuresuch as not using respiratory and eye protectionto prevent infection and illness. When influenza viruses evolve, it can make treatment less effective. The CDC regularly tests bird flu viruses for antiviral resistance.
Is there a vaccine for the A(H5N1) virus?
There are H5 candidate vaccine viruses that could be used to produce a vaccine. According to the
U.S. Department of Health and Human Services assistant secretary for preparedness and response, officials are moving ahead with a plan to produce 4.8 million doses of H5N1 avian flu vaccine for pandemic preparedness. Active discussions are underway across federal agencies about what the key triggers would be for deploying H5N1 vaccine doses.
What measures are being taken to control the spread of A(H5N1) virus?
Testing for the flu typically declines over the summer, but the CDC is working on a plan for enhanced nationwide monitoring to ensure that even rare cases of A(H5N1) virus in the community are detected. This includes increasing the number of influenza virus specimens that are tested and then subtyped in public health laboratories that can detect A(H5N1) virus.
Additionally, the federal government is offering financial incentives to dairy-farm owners to encourage broader testing of cattle and expand biosecurity measures to control the growing outbreak. It is only available to farms with infected herds. Testing of cattle and farm workers is important to controlling this outbreak.
What can I do to protect myself and my family from the A(H5N1) virus?
Since the A(H5N1) virus is not spreading among humans, most people dont need to worry about precautions. But the best prevention is to avoid sources of exposure. That means avoiding direct contact with wild birds and other animals infected with, or suspected to be infected with, bird flu viruses. Notably, wild birds can be infected with avian influenza even if they dont look sick.
It is also important to avoid being near dead animals or surfaces contaminated with an animals feces or litter, raw milk, saliva, mucous or other byproducts when not wearing respiratory or eye protection. And, as always, people should not eat uncooked or undercooked food. They should avoid uncooked food products such as unpasteurized raw milk or cheeses from animals who have a suspected or confirmed infection, the CDC says.
Is it OK to drink milk?
The FDA has been sampling retail milk and other dairy products. To date, they have not found live, infectious virus in the products.
The CDC issued a Health Alert Network Health Advisory with recommendations that support consumption of only pasteurized milk and dairy products made from pasteurized milk. Most of the nutritional benefits of drinking milk are available from pasteurized milk. It is important not to consume unpasteurized raw milk or products made from unpasteurized milk because it can contain bacteria or viruses, such as A(H5N1) virus, that can cause serious illness, hospitalization or death. The CDC has developed advice for health care professionals on raw milk (PDF).
Can I get A(H5N1) virus from eating poultry or eggs?
There is no evidence that the virus can be transmitted to humans through properly prepared food. Cooking poultry, eggs and other animal products to the proper temperature and preventing cross contamination between raw and cooked food are key to preventing any food safety hazard, including infection from the A(H5N1) virus, according to the FDA .
What should I do if I find a dead bird?
It is important to avoid contact with wild or domestic birds that appear ill or have died. If you do encounter a sick or dead bird, call to report it because wildlife agencies regularly investigate reports of sick or dead animals. This type of reporting can help with early detection of illnesses such as the bird flu or West Nile virus, according to the CDC.
Is it safe to travel to areas where cases of A(H5N1) virus have been reported?
The CDC does not have any travel restrictions related to the bird flu to states or countries affected by avian influenza in wild birds, poultry, other animals or people. But travelers to countries or states with bird-flu outbreaks in poultry or people should not visit poultry farms, bird markets or other places where live poultry are raised, kept or sold.
When travelingjust as at homedo not eat raw or undercooked poultry products and wash your hands after touching uncooked poultry. Beyond that, practice good hygiene and visit a doctor if you become sick during or after travel.
CAMBRIDGE - Moderna announced Monday that its combination COVID and flu vaccine showed positive results in a late-stage trial.
The Cambridge, Massachusetts-based biotech company said the mRNA-1083 vaccine produced a higher immune response in older adults than the separate shots that were co-administered in the study.
"Combination vaccines have the potential to reduce the burden of respiratory viruses on health systems and pharmacies, as well as offer people more convenient vaccination options that could improve compliance and provide stronger protection from seasonal illnesses," Moderna CEO Stephane Bancel said in a statement Monday. "Moderna is the only company with a positive Phase 3 flu and COVID combination vaccine.
The Phase 3 trial involved two groups of about 4,000 adults each. One group consisted of adults between the 50 and 64 years old and the other was just for those above 65. In the older group, the combination vaccine was compared to a higher dose flu shot.
"In both age cohorts, mRNA-1083 also elicited statistically significantly higher immune responses against three influenza virus strains (H1N1, H3N2, and B/Victoria) and against SARS-CoV-2," Moderna reported.
The company said the trial showed the new combination vaccine has "an acceptable tolerability and safety profile." The most commonly reported side effects were injection site pain, fatigue, muscle pain and headaches.
Back in early 2022, Moderna said it was planning to have a combination COVID and flu vaccine ready by the fall of 2023. Many months later, it's still not clear when the public will have access to the shot.
Moderna said it "will engage with regulators on next steps" for its combination vaccine. In aletter to shareholders at the start of the year, Bancel said the intention is to have the combination vaccine ready as early as 2025.
Speaking to CBS News last fall as Moderna prepared to begin the late-stage trial, Montclair State University public health professor Dr. Stephanie Navarro Silvera said a combination vaccine would be more appealing for people who don't like getting multiple shots.
"Let's face it, nobody wants to get a shot more than once," she said. "So if we can combine two vaccines into one ... that's going to be a win in terms of public health."
Moderna's competitors are also working on a combination shot. Pfizer and BioNTech said last October that it was preparing a Phase 3 trial after getting "positive topline results" in earlier studies. And Novavax's website says a COVID and seasonal influenza vaccine is in the Phase 2 trial stage.
Neal J. Riley is a digital producer for CBS Boston. He has been with WBZ-TV since 2014. His work has appeared in The Boston Globe and The San Francisco Chronicle. Neal is a graduate of Boston University.
Read More
Bird flu
Scientists are on alert for signs the virus is adapting to spread more easily among humans, after the WHO announced the death from April
Guardian staff and agencies
The World Health Organization (WHO) has said a mans death in Mexico was caused by a strain of bird flu called H5N2 that has never before been found in a human.
The WHO said Wednesday it wasnt clear how the person became infected. Although the source of exposure to the virus in this case is currently unknown, A(H5N2) viruses have been reported in poultry in Mexico, it said in a statement.
Scientists are on alert for changes in the virus that could signal that bird flu is adapting to spread more easily among humans.
But the UN agency said Wednesday said the current risk of the bird flu virus to the general population in Mexico is low.
The 59-year-old man, who had been hospitalised in Mexico City, died on 24 April after developing a fever, shortness of breath, diarrhoea, nausea and general discomfort, the WHO said.
Mexicos health ministry added in a statement on Wednesday that there had so far been no evidence of person-to-person transmission of bird flu in the case of the man who died, and that he had several prior health conditions. All people who had contact with him have tested negative, it said.
In March, Mexicos government reported an outbreak of A(H5N2) in an isolated family unit in the countrys western Michoacan state, but said at the time it did not represent a risk to distant commercial farms, nor to human health.
After the April death, Mexican authorities confirmed the presence of the virus and reported the case to the WHO, the agency said.
There had been three poultry outbreaks of H5N2 in nearby parts of Mexico in March, but authorities havent been able to find a connection.
Scientists said the case in Mexico is unrelated to the outbreak of a different strain of bird flu H5N1 in the United States that has so far infected three dairy farm workers.
Other bird flu varieties have killed people across the world in previous years, including 18 people in China during an outbreak of H5N6 in 2021, according to a timeline of bird flu outbreaks from the US Centers for Disease Control and Prevention.
Andrew Pekosz, an influenza expert at Johns Hopkins University said that since 1997, H5 viruses have continuously shown a propensity to infect mammals more than any other avian influenza virus.
So it continues to ring that warning bell that we should be very vigilant about monitoring for these infections, because every spillover is an opportunity for that virus to try to accumulate those mutations that make it better infect humans, he said.
Cases of bird flu have now been identified in mammals such as seals, raccoons, bears and cattle, primarily due to contact with infected birds.
Australia reported its first human case of A(H5N1) infection in May, noting there were no signs of transmission. It has however found more poultry cases of H7 bird flu on farms in the state of Victoria.
With Reuters and Associated Press
{{topLeft}}
{{bottomLeft}}
{{topRight}}
{{bottomRight}}
{{.}}
One-timeMonthlyAnnual
Other
The World Health Organization (WHO) has confirmed that a four-year-old child in West Bengal, India, has been infected with the H9N2 bird flu virus.
The child was admitted to a local hospital's pediatric intensive care unit in February, suffering from severe respiratory issues, high fever, and abdominal cramps. After receiving the diagnosis and treatment, the child was discharged three months later.
The WHO reported that the child had been exposed to poultry at home and in the surrounding area. No other family members or contacts have reported respiratory symptoms. Details on the child's vaccination status and antiviral treatment were not available at the time of reporting.
Read More
This case marks the second instance of human infection with the H9N2 strain of bird flu in India, following the first reported case in 2019. While H9N2 typically causes mild illness, the WHO warned that sporadic human cases may continue to occur, given the virus's prevalence in poultry across various regions.
ALL ABOUT THE H9N2 BIRD FLU STRAIN
The H9N2 strain is a subtype of the avian influenza virus, commonly found in birds. This is the second case of H9N2 in India.
"While it primarily infects birds, it can occasionally infect humans, including children," said Dr Saibal Chakravorty, Senior Consultant, Internal Medicine, Metro Hospital, Noida.
Direct contact with infectious animals or indirect interaction with contaminated environments are the two ways that the virus spreads.
Common symptoms of H9N2 are familiar to other viral infections. Individuals may experience fever, cough, sore throat, runny or stuffy nose, and headache. Other symptoms could include muscle aches, fatigue, and conjunctivitis.
In some cases, severe symptoms like difficulty breathing and pneumonia can occur.
It can occasionally lead to more severe illness, especially in individuals with weakened immune systems or underlying health conditions.
"In comparison to other strains of avian influenza, such H5N1 and H7N9, H9N2 is typically less infectious and results in a milder illness in humans. It is well established that H5N1 and H7N9 can cause serious respiratory illnesses and increase an infected person's mortality rate," said Dr Chakravorty.
H9N2 is less hazardous to public health due to its comparatively lower pathogenicity, but regular observation is still necessary because of its global distribution and human infection potential.
TREATMENT FOR H9N2 BIRD FLU
Multiple techniques are used to manage and treat H9N2 avian influenza.
Antiviral medications like zanamivir (Relenza) and oseltamivir (Tamiflu) can be helpful, especially if used early in the course of the illness.
It's also critical to provide supportive care, which includes relaxation, adequate hydration, and treatment of fever and respiratory problems.
In severe circumstances, the patient may need to be admitted to the hospital for intensive care and respiratory support in order to obtain the essential medical attention to adequately manage the infection.
"Generally, H9N2 is less dangerous than other more virulent strains of avian influenza; but, because of its ability to disseminate and infect people, especially those who have close contact with birds, continuous surveillance and preventive measures are necessary," underscored Dr Chakravorty.
Published By:
Daphne Clarance
Published On:
Jun 12, 2024
The strain of H5N1 bird flu isolated from a dairy worker in Texas was 100 percent fatal in ferrets used to model influenza illnesses in humans. However, the virus appeared inefficient at spreading via respiratory droplets, according to newly released study results from the Centers for Disease Control and Prevention.
"This suggests that A/Texas/37/2024-like viruses would need to undergo changes to spread efficiently by droplets through the air, such as from coughs and sneezes," the CDC said in its data summary. The agency went on to note that "efficient respiratory droplet spread, like what is seen with seasonal influenza viruses, is needed for sustained person-to-person spread to happen."
In the CDC's study, researchers infected six ferrets with A/Texas/37/2024. The CDC's data summary did not specify how the ferrets were infected in this study, but in other recent ferret H5N1 studies, the animals were infected by putting the virus in their noses. Ars has reached out to the agency for clarity on the inoculation route in the latest study and will update the story with any additional information provided.
All six of the infected ferrets developed severe disease and died. To test how well the virus could spread among the ferrets, the CDC scientists set up experiments to test transmission through direct contact and respiratory droplets. For the direct transmission test, three healthy ferrets were placed in the same enclosures with three experimentally infected ferrets. All three healthy ferrets became infected.
For the respiratory transmission test, three healthy ferrets were placed in enclosures next to enclosures containing the experimentally infected animals. The infected and uninfected ferrets shared air, but did not have direct contact with each other. Of the three healthy ferrets, only one contracted the H5N1 virus (33 percent). Additionally, that one respiratory transmission event seemed to have a one- to two-day delay compared with what's seen in the same test with seasonal influenza viruses. This suggests further that the virus is inefficient at respiratory transmission.
The CDC called the overall results "not surprising." Previous ferret experiments with H5N1 isolatescollected prior to the current bird flu outbreak among US dairy cowshave also found that H5N1 is often lethal to ferrets. Likewise, H5N1 isolates collected from Spain and Chile during the current global outbreak also found that the virus was inefficient at spreading via respiratory droplets among ferretswith rates ranging from 0 percent to 37.5 percent.
For now, the findings don't affect the CDC's overall risk assessment for the general public, which is low. However, it does reinforce the risk to those who have contact with infected animals, particularly dairy and poultry farm workers.
To date, there have been four human cases of H5N1 in the US since the current global bird flu outbreak began in 2022one in a poultry farm worker in 2022 and three in dairy farm workers, all reported between the beginning of April and the end of May this year. So far, the cases have been mild, the CDC noted, but given the results in ferrets, "it is possible that there will be serious illnesses among people," the agency concluded.
As of June 9, the US Department of Agriculture has confirmed H5N1 in 85 dairy herds and one alpaca farm across 10 states.
REUTERS The ongoing U.S. outbreak of avian flu in dairy cattle reached Minnesota last week as the state announced its first infected herd.
Glacier FarmMedia ROTTERDAM Many major crop-producing regions, Canada among them, now have a pathway to market gene-edited crops
More than 80 dairy herds have been infected with the virus across 11 states since late March, and three dairy workers have tested positive for the virus.
The Minnesota Board of Animal Health said the farmer of the affected herd reported more than 40 cows with signs of fever. The animals were tested and the U.S. Department of Agricultures National Veterinary Services Laboratories confirmed the positive test.
We knew it was only a matter of time before this detection would reach our doorstep, said Brian Hoefs, the state veterinarian, in a statement. Its important for dairy farmers to follow the example of this herd and test sick cows.
The other states with infected herds include Idaho, Colorado, South Dakota, Kansas, New Mexico, Texas, Michigan, Ohio, Iowa and North Carolina.
Dairy cows with avian flu have died or been slaughtered by farmers after not recovering, Reuters reported. The U.S. Department of Agriculture said most cows recover.
A 59-year-old man with underlying health conditions died in a Mexico City hospital on April 24 from complications due to contracting A[H5N2] strain of bird flu, according to the World Health Organization. The man reportedly had not been exposed to poultry or other animals.
The bird flu virus strain that infected a Texas dairy farm worker in March was lethal to ferrets in experiments designed to mimic the disease in humans, the U.S. Centers for Disease Control and Prevention reported. Seasonal flu, by contrast, makes ferrets sick but does not kill them, the CDC said.
Ferrets are considered the best small mammal for studying influenza virus infection and transmission and are commonly used as a tool to inform public health risk assessments of emerging influenza viruses, according to the CDC.
The strain of avian influenza virus found in Texas spread easily among healthy ferrets when they were placed in direct contact with infected ferrets, the researchers found.
The virus was less efficient than other influenza strains at spread by respiratory droplets, however.
This suggests viruses like this one would need to undergo changes to spread efficiently by droplets through the air, such as from coughs and sneezes, the CDC said.
Bird flu has been found in seals in the United Kingdom, Denmark and Germany.
The EU recently signed a contract to secure more than 40 million doses of a preventive avian flu vaccine for 15 countries. The first shipments will go to Finland.
The deal secures up to 665,000 doses from vaccine manufacturer CSL Seqirus and includes an option for a further 40 million vaccines for a maximum of four years.
There were no active cases in humans or in cattle in the EU as of early June, according to the European Centre for Disease Prevention and Control.
Transmission to humans remains a rare event and no sustained transmission between humans has been observed so far, it said in a weekly report for June 1-7.
The risk of zoonotic influenza transmission to the general public in EU/EEA countries is considered to be low.
The World Health Organization recently said the child with H5N1 bird flu reported by Australia last month had traveled to Kolkata, India, and the family said they did not have any known exposure to infected people or animals while there.
The World Health Organisation has confirmed a case of human infection with the H9N2 bird flu virus in a four-year-old child from West Bengal, India. The child, who was hospitalised with severe respiratory issues, high fever, and abdominal cramps, has now been discharged after receiving treatment.
The WHO stated that the patient had been in contact with poultry at home and in the vicinity, with no reports of respiratory illness symptoms among family members or other contacts. Details regarding vaccination status and antiviral treatment were not disclosed at the time of the report.
This marks the second recorded case of H9N2 bird flu infection in humans in India. The first one was recorded in 2019. While the virus typically leads to mild illness, the WHO cautioned that sporadic human cases could still arise, as H9N2 is among the most prevalent avian influenza viruses found in poultry across various regions.
As of the latest update, there has been no immediate response from the Indian health ministry regarding this incident.
About H9N2 virus
- H9N2 is a subtype of the avian influenza virus, commonly found in birds, and it is the second case of H9N2 in India. - The virus spreads through direct contact with infectious animals or indirect interaction with contaminated environments. - Common symptoms of H9N2 include:
- Severe symptoms like difficulty breathing and pneumonia can also occur. - It can lead to more severe illness, especially in individuals with weakened immune systems or underlying health conditions. - H9N2 is less infectious and results in a milder illness than other avian influenza strains such as H5N1 and H7N9.
Treatment
- Treatment for H9N2 bird flu includes anti-viral medications like zanamivir (Relenza) and oseltamivir (Tamiflu) if used early in the illness, as well as supportive care like relaxation, hydration, and treatment of fever and respiratory problems. - In severe cases, hospitalisation for intensive care and respiratory support may be required to manage the infection effectively. - Due to H9N2's global distribution and potential for human infection, continuous surveillance and preventive measures are necessary.
This article is republished from The Conversation under a Creative Commons license.
Recent outbreaks of bird fluin US dairy herds, poultry farms in Australia, and elsewhere, and isolated cases in humanshave raised the issue of food safety.
So can the virus transfer from infected farm animals to contaminate milk, meat, or eggs? How likely is this? And what do we need to think about to minimize our risk when shopping for or preparing food?
Bird flu (or avian influenza) is a bird disease caused by specific types of influenza virus. But the virus can also infect cows. In the US, to date, more than 80 dairy herds in at least nine states have been infected with the H5N1 version of the virus.
Investigations are under way to confirm how this happened. But we do know that infected birds can shed the virus in their saliva, nasal secretions, and feces. So bird flu can potentially contaminate animal-derived food products during processing and manufacturing.
Indeed, fragments of bird flu genetic material (RNA) were found in cows milk from the dairy herds associated with infected US farmers.
However, the spread of bird flu among cattle, and possibly to humans, is likely to have been caused through contact with contaminated milking equipment, not the milk itself.
The test used to detect the virus in milkwhich uses PCR technology similar to lab-based Covid testsis also highly sensitive. This means it can detect very low levels of the bird flu RNA. But the test does not distinguish between live or inactivated virus, just that the RNA is present. So from this test alone, we cannot tell if the virus found in milk is infectious (and capable of infecting humans).
Does that mean milk is safe to drink and wont transmit bird flu? Yes and no.
In Australia, where bird flu has not been reported in dairy cattle, the answer is yes. It is safe to drink milk and milk products made from Australian milk. In the US, the answer depends on whether the milk is pasteurized. We know pasteurization is a common and reliable method of destroying concerning microbes, including influenza virus. Like most viruses, influenza virus (including bird flu virus) is inactivated by heat.
Although there is little direct research on whether pasteurization inactivates H5N1 in milk, we can extrapolate from what we know about heat inactivation of H5N1 in chicken and eggs. So we can be confident there is no risk of bird flu transmission via pasteurized milk or milk products.
However, its another matter for unpasteurized or raw US milk or milk products. A recent study showed that mice fed raw milk contaminated with bird flu developed signs of illness. So to be on the safe side, it would be advisable to avoid raw milk products.
Bird flu has caused sporadic outbreaks in wild birds and domestic poultry worldwide, including in Australia. In recent weeks, there have been three reported outbreaks in Victorian poultry farms (two with H7N3 bird flu, one with H7N9). There has been one reported outbreak in Western Australia (H9N2).
The strains of bird flu identified in the Victorian and Western Australia outbreaks can cause human infection, although these are rare and typically result from close contact with infected live birds or contaminated environments. Therefore, the chance of bird flu transmission in chicken meat is remote.
The World Health Organisation (WHO) said a case of human infection with bird flu caused by the H9N2 virus was detected in a four-year-old child in West Bengal.
The patient was admitted to the pediatric intensive care unit (ICU) of a local hospital due to persistent severe respiratory issues, high fever and abdominal cramps in February, and was discharged three months later after diagnosis and treatment.
The patient had exposure to poultry at home and in his surroundings, and there were no known persons reporting symptoms of respiratory illness among his family and other contacts.
This is the second human infection of H9N2 bird flu from India, with the first in 2019.
While the H9N2 virus typically tends to cause mild illness, the WHO said that further sporadic human cases could occur as this virus is one of the most prevalent avian influenza viruses circulating in poultry in different regions.
Bird flu (Avian Influenza)
Bird flu (Avian Influenza) is a contagious viral disease affecting several species of food producing birds (chickens, turkeys, quails, guinea fowl, etc), as well as pet birds and wild birds.
Occasionally mammals, including humans, may contract Avian Influenza, says World Organisation For Animal Health (OIE).
Avian Influenza has captured the attention of the international community over the years, with outbreaks in poultry having serious consequences on both livelihoods and international trade in many countries.
India notified the first outbreak of Avian Influenza in 2006. Since then, outbreaks have been reported in many states. The disease spreads mainly by migratory birds coming into India during winter months, SeptemberOctober to FebruaryMarch.
Human infection with Avian Influenza
Although most Avian Influenza viruses do not infect humans, some, such as Avian Influenza H5N1, H7N9 and H9N2, are well known to the public because of their implication in serious and sometimes fatal infections in people.
H5N1, for example, a highly pathogenic AI virus, was initially diagnosed in humans in Hong Kong in 1997. The virus then re-emerged in 2003 and 2004, and spread from Asia to Europe and Africa causing several hundred human cases and deaths, as well as destruction of hundreds of millions of poultry.
This Asiatic form of H5N1 triggered concern from scientists and authorities and remains under close surveillance due to its feared pandemic potential if a mutation allows it to be transmitted from human to human.
Nowadays, due to ongoing circulation of various strains (H5N1, H5N2, H5N8, H7N8, etc), outbreaks of Avian Influenza continue to be a global public health concern.
From January 1, 2003 to December 21, 2023, a total of 248 cases of human infection with Avian Influenza A(H5N1) virus were reported from four countries within the Western Pacific Region. Of these cases, 139 were fatal.
As of January 31, 2024, a total of 90 laboratory-confirmed cases of human infection with influenza A(H5N6) virus including 35 deaths were reported to WHO in the Western Pacific Region since 2014. The last case was reported from China on November 25, 2023.
As of January 31, 2024, a total of three laboratory-confirmed cases of human infection with influenza A(H3N8) virus with one death were reported to WHO in the Western Pacific Region.
Highly Pathogenic Avian Influenza
During 2020, Highly Pathogenic Avian Influenza (HPAI) A(H5N1) clade 2.3.4.4b viruses arose from previously circulating influenza A(H5Nx) viruses and spread predominantly via migratory birds to many parts of Africa, Asia and Europe.
The epizootic (a disease event in an animal population akin to an epidemic in humans) has led to unprecedented numbers of deaths in wild birds and caused outbreaks in domestic poultry.
In late 2021, these viruses crossed to North America and subsequently South America in October 2022.
Globally, there have been increased detections of A(H5N1) viruses in non-avian species including wild and domestic (including companion and farmed) terrestrial and marine mammals and, more recently in goats and dairy cattle in the US.
Avian Influenza A(H5N1) viruses, especially those of clade 2.3.4.4b, continue to diversify genetically and spread geographically.
Since 2022, a broader range of wild bird species has been infected globally which has had deleterious ecological consequences and caused mass die-offs in some species. The situation with wild mammals is also worrying, with some species suffering significant mortality events.
HPAI is an extremely contagious, multi-organ systemic disease of poultry leading to high mortality, and caused by some H5 and H7 subtypes of type A influenza virus.
HPAI viruses pose a threat to wild birds and poultry globally. HPAI H5N1 viruses are of even greater concern because of their frequent spillover into mammals.
Since the beginning of 2021, as many as 28 detections of A(H5N1) in humans have been reported to WHO, including a case who had exposure to dairy cattle presumed to be infected with A(H5N1) virus.
Although human infections with HPAI A(H5N1) virus are rare, having unprotected exposure to any infected animal or to an environment in which infected birds or other animals are or have been present can pose a risk of infection.
Therefore, people with work or recreational exposures to A(H5N1) virus-infected animals may be at increased risk of infection and should follow recommended precautions.
WASHINGTON (AP) A mans death in Mexico was caused by a strain of bird flu called H5N2 that has never before been found in a human, the World Health Organization said Wednesday.
The WHO said it wasnt clear how the man became infected, although H5N2 has been reported in poultry in Mexico.
There are numerous types of bird flu. H5N2 is not the same strain that has infected multiple dairy cow herds in the U.S. That strain is called H5N1 and three farmworkers have gotten mild infections.
Other bird flu varieties have killed people across the world in previous years, including 18 people in China during an outbreak of H5N6 in 2021, according to a timeline of bird flu outbreaks from the U.S. Centers for Disease Control and Prevention.
Mexican health officials alerted the WHO that a 59-year-old man who died in a Mexico City hospital had the virus despite no known exposure to poultry or other animals.
According to family members, the WHO release said, the patient had been bedridden for unrelated reasons before developing a fever, shortness of breath and diarrhea on April 17. Mexicos public health department said in a statement that he had underlying ailments, including chronic kidney failure, diabetes and high blood pressure.
Hospital care was sought on April 24 and the man died the same day.
Initial tests showed an unidentified type of flu that subsequent weeks of lab testing confirmed was H5N2.
The WHO said the risk to people in Mexico is low, and that no further human cases have been discovered so far despite testing people who came in contact with the deceased at home and in the hospital.
There had been three poultry outbreaks of H5N2 in nearby parts of Mexico in March but authorities havent been able to find a connection. Mexican officials also are monitoring birds near a shallow lake on the outskirts of Mexico City.
Whenever bird flu circulates in poultry, there is a risk that people in close contact with flocks can become infected. Health authorities are closely watching for any signs that the viruses are evolving to spread easily from person to person, and experts are concerned as more mammal species contract bird flu viruses.
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institutes Science and Educational Media Group. The AP is solely responsible for all content.
