Avian influenza, or bird flu, has public health officials on alert after an unprecedented spread in dairy cows in the United States this year. Four dairy workers have also tested positive in the country.

A particularly severe variant of the H5N1 strain has been spreading around the world in animals since 2020, causing lethal outbreaks in commercial poultry and sporadic infections in other species from alpacas to house cats. Until this year, it had never infected cows.

Different bird flu strains have been found in Australia and Mexico in humans, while different H5 subtypes are also present around the world in both animals and humans, in countries including China and Cambodia.

Most of the human cases reported exposure to poultry, live poultry markets, or dairy cattle prior to infection, but scientists are worried the virus could mutate in ways that make it more easily spread from person-to-person, which could spark a pandemic. The World Health Organization says the risk to people is low at this point.

Below are occurrences of varying types of the bird flu virus that have been found in humans this year.

UNITED STATES:

The first known cases of infected dairy cattle occurred in Texas in March, and is now in dairy herds in 12 states. The U.S. Agriculture Department said tests so far indicate that the virus detected in cows is the same H5N1 virus affecting wild birds and commercial poultry flocks. The four dairy workers who have tested positive for the virus this year had mild symptoms such as conjunctivitis, or pink eye.

The H5N1 virus in the United States belongs to the clade 2.3.4.4b, genotype B3.13, a genotype detected only in North America so far, the European Food Safety Agency said in a scientific report.

MEXICO:

A resident of Mexico died with the first known cases of H5N2 avian influenza in humans, the WHO said on June 5. Mexico’s government said chronic illness, rather than bird flu, was the cause of death. The person had no known exposure to animals.

AUSTRALIA:

The WHO on June 7 said a child with H5N1 bird flu reported by Australia had traveled to Kolkata, India. Genetic sequencing showed the virus was a subtype of H5N1 and part of a strain that circulates in Southeast Asia and has been detected in previous human infections and in poultry.

Australia is separately dealing with three outbreaks of different strains of the virus on poultry farms – H7N3, H7N8 and H7N9 – that authorities say likely arrived on farms via wild birds.

INDIA:

The WHO on June 11 reported a case of human infection with bird flu caused by the H9N2 subtype in a four-year-old child in the eastern Indian state of West Bengal. It was the second human infection of H9N2 bird flu from India following a case in 2019, the agency said. While the H9N2 virus typically tends to cause mild illness, the United Nations agency said further sporadic human cases could occur as this is one of the most prevalent avian influenza viruses circulating in poultry in different regions.

VIETNAM:

Vietnam reported a 21-year-old student had died from the H5N1 bird flu in March. He had no underlying medical conditions, but had been exposed to wild birds from hunting a couple of weeks prior to onset of symptoms. No contact with dead or sick poultry was reported at the time.

Vietnam also reported an outbreak of H9N2 in a 37-year-old man, EFSA said.

CAMBODIA:

The Southeast Asia nation and Vietnam neighbor has reported five human cases of H5N1 as of June 20.

CHINA:

China this year detected human cases caused by the H5N6, H9N2 and H10N3 strains, with two fatal H5N6 cases in the Fujian province. Both of those cases had exposure to backyard poultry before the onset of symptoms, EFSA said.

The case of H10N3 avian influenza was the third one ever reported globally.

GERMANY:

Germany reported a rare outbreak of highly pathogenic H7N5 bird flu on a farm in the western part of the country, near the border with the Netherlands, the World Organisation for Animal Health said on July 4. It was the first outbreak anywhere of H7N5 on WOAH’s public records.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

New Delhi:

The Centre has asked all states to be vigilant for any unusual deaths amongst the domestic birds and poultry, and share the information with the Animal Husbandry Department immediately so that public health action can be initiated as per the national action plan for Avian influenza.

A joint advisory issued on May 25 by the National Centre for Disease Control (NCDC) and Department of Animal Husbandry and Dairying stated that in 2024, four states — Andhra Pradesh (Nellore), Maharashtra (Nagpur), Kerala (Alappuzha, Kottayam, and Pathanamthitta districts), and Jharkhand (Ranchi) — have already reported outbreaks of Avian influenza in poultry.

“Given that Avian Influenza (H5N1) infection is highly pathogenic and has the potential to be transmitted to humans, it is imperative to take all necessary measures to minimize and prevent the spread of this infection,” the joint advisory said.

The Avian Influenza virus (bird flu virus) is normally maintained in circulation in nature among mainly migratory birds and is known to cause outbreaks among domesticated poultry birds probably due to spill over events when migratory birds come in contact with poultry, it said.

The H5N1 is the main Avian influenza virus that has caused multiple outbreaks among poultry globally. Both types of viruses (HPAI and LPAI) may occasionally affect other mammalian species, including humans.

Human infections are primarily acquired through direct contact with infected poultry or contaminated environments, the joint advisory said.

Although there have been sporadic reports in humans and outbreaks among domestic and wild birds, since March 2024, there is a global concern over Avian influenza outbreaks in cattle from multiple states in the US that have resulted in one reported human case of H5N1, the joint advisory stated.

Avian influenza outbreaks from India in poultry have been reported since 2006 and have been jointly investigated by the Animal Husbandry and Health Departments (IDSP, NCDC).

The states and Union Territories have been advised to orient all the health care workers/private practitioners on case definitions, signs and symptoms of Avian influenza.

“Be vigilant for any unusual deaths amongst the domestic birds/poultry in your state, and if observed, please share the information immediately with the Department of Animal Husbandry so that public health action can be initiated as per the national action plan for Avian Influenza,” the joint advisory said.

The states have been advised to strengthen biosecurity measures in all poultry establishments, zoos, poultry markets, etc. after conducting a thorough assessment.

“Comprehensive biosecurity assessments on all poultry farms are recommended. Access to farms should be restricted and stringent hygiene protocols, including the use of disinfectant footbaths and protective clothing, should be enforced. Measures to prevent contact between wild birds and domestic poultry should be implemented,” it stated.

The states have been asked to enhance information, education and communication tools among the general public regarding preventive measures such as minimizing the handling of dead or sick birds with bare hands and without adequate respiratory protection and following food safety measures while consuming products of animal origin.

Besides, they have been asked to be prepared for all preventive measures like stockpiling of an adequate number of antiviral drugs (Oseltamivir), PPE, masks etc.

Isolation wards/beds at dedicated hospitals may be required to handle any suspect case of Avian Influenza if confirmation among birds occurs in your state, the joint advisory stated.

It also called for enhanced surveillance (in wet markets, abattoirs, poultry farm workers etc.) as well as expanded surveillance (in sewage samples, water bodies, crows etc.) for Avian Influenza in collaboration with National Centre for Disease Control (NCDC), Indian Council of Medical Research (ICMR) and Department of Animal husbandry and Dairying (DAHD).

It emphasised on timely sharing of information besides underlined the need for strict compliance with the SARI surveillance guidelines of the Ministry of Health and Family Welfare by all states and its monitoring at senior level.

For the states where there is an active outbreak of Avian Influenza, the joint advisory advised some additional measures.

They have been asked to collect samples from cullers and surveillance workers (considered as ‘at-risk’ groups) on the 5th and 10th days following sanitization operations for H5N1 testing.

The joint advisory has stressed on conducting surveillance for suspected human cases and providing health check-ups for cullers and poultry workers, with a duration of 10 days and stated that recommended measures for chemoprophylaxis, management, and use of personal protective equipment (PPE) should be implemented.

It also advised following the SOPs for collecting and transporting samples from suspected cases to designated laboratories.

“A coordinated response involving experts from veterinary services, health departments, wildlife and forest departments, local authorities and other relevant stakeholders is required in all Avian Influenza outbreaks. Regular meetings should be conducted to share information, assess the situation and adjust strategies accordingly,” the joint advisory said.
 

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

Washington, United States:

US officials on Thursday reported the country’s third human case of bird flu linked to the current outbreak of the virus in dairy cattle.

The Michigan farm worker is the second person sickened by the disease in the Midwestern state, following a first case in Texas in April.

The Centers for Disease Control and Prevention (CDC) said in a statement all three cases were spread from cows to humans, as opposed to human-to-human, which would be more concerning.

But it added it was the first case “to report more typical symptoms of acute respiratory illness associated with influenza virus infection,” while the previous cases resulted in mild symptoms including conjunctivitis.

The person’s symptoms included cough without fever, eye discomfort and watery eye discharge. They were treated with the antiviral medicine oseltamivir and isolated at home, with their symptoms resolving.

The worker was not wearing personal protective equipment, which health authorities have recommended for those in close contact with dairy herds, said Michigan’s health department.

Over the past few years, a highly pathogenic avian influenza virus called HPAI H5N1 has spread to infect more than 50 animal species, including, from March, dairy cattle in the United States.

Unlike in Europe, American farmers are allowed to feed cattle ground-up chicken waste, which some scientists say may be a risk factor for bird flu — though the feed industry has challenged this claim and US authorities believe wild birds are responsible for infecting cows.

“The risk to members of the general public who do not have exposure to infected animals remains low,” said the CDC.

It added that finding a new case was “not surprising” because Michigan was proactively testing for cases among farmworkers.

In addition to using PPE, people should avoid close exposure to sick or dead animals including wild birds, domesticated birds and other domesticated animals, according to the CDC.

They should also avoid touching animal excrement or bedding, or consuming unpasteurized milk, the agency added.

Recent testing has confirmed mice are sickened by exposure to raw milk contaminated with bird flu, but pasteurization destroys the virus.

Most recently, the disease has been found in farm-raised alpacas in Idaho.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

Washington:

Mice fed raw cow’s milk infected with bird flu experienced high levels of the virus in their lungs, according to a study published Friday that suggests risk to humans who consume the drink.

Over the past few years, a highly pathogenic avian influenza virus called HPAI H5N1 has spread to infect more than 50 animal species, including, from March, dairy cattle in the United States.

To date, 52 herds across the country have been affected, with two human infections involving farm workers who developed mild symptoms, including pink eye.

In the new study, published in the New England Journal of Medicine, researchers from the University of Wisconsin-Madison and Texas A&M fed droplets of raw milk from infected cattle to five mice.

The rodents developed signs of illness, including lethargy, and were then euthanized four days later to study their organs.

The researchers found high levels of virus in their nasal passages, trachea and lungs, and moderate-to-low levels of virus in other organs.

“An important consideration is that the consumption of raw, unpasteurized milk is becoming increasingly popular,” said Rowland Kao, a professor of veterinary epidemiology at the University of Edinburgh, who was not involved in the research.

Raw milk laws vary by state in the US, with some permitting its sale in retail stores, others only allowing it to be sold on the farm it was produced, and others still prohibiting it altogether.

An official 2019 survey found that 4.4 percent of adults said they had consumed raw milk in the past year. Such consumers tended to be younger and lived in rural areas.

“While this study shows that mice can become systemically infected due to ingesting infected milk, this does not prove that the same is true for humans, though it does increase the possibility,” added Kao.

In addition to the mice tests, the research confirmed that heating raw milk to high temperatures destroys nearly all virus after a few seconds, and completely destroys the pathogen after several minutes.

A recent nationwide survey of pasteurized milk found all samples were negative for viable virus, though inactivated virus, no longer capable of spreading or infecting a host, was found in about 20 percent of retail samples.

Finally, the researchers tested the effect of storing infected raw milk at fridge temperatures and found that the virus levels declined only slightly after five weeks, indicating that refrigeration alone is not sufficient to make raw milk safe.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

Washington:

 The U.S. CDC on Friday issued a health alert to inform clinicians, state health departments and the public of a case of avian influenza in a person who had contact with dairy cows presumed to be infected with the virus.

The farm worker from Texas was reported to be infected on April 1, making it the second case of the H5N1 strain of avian influenza, commonly known as bird flu, identified in a person in the United States.

It follows a 2022 case in Colorado, and comes as the virus is spreading to new mammals, including dairy cattle for the first time.

To prevent infection from the virus, the CDC recommends the use of personal protective equipment (PPE), testing, antiviral treatment, patient investigations and monitoring of persons exposed to sick or dead, wild and domesticated animals and livestock that may have been infected with the virus.

Earlier this week, the CDC said the infection does not change the risk assessment for the U.S. general public from H5N1 bird flu, which it considers to be low. The Texas patient’s only symptom was eye inflammation, according to the state’s health department.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

The deadly H5N1 bird flu virus has spread more aggressively than ever before in wild birds and marine mammals since arriving in South America in 2022, raising the risk of it evolving into a bigger threat to humans, according to interviews with eight scientists.

Of more immediate concern is evidence the disease, once largely confined to bird species, appears to be spreading between mammals. This strain has already killed a handful of dolphins in Chile and Peru, some 50,000 seals and sea lions along the coasts, and at least half a million birds regionwide.

To confirm mammal-to-mammal transmission, scientists would likely need to test infections in live animals.

“It’s almost certainly happened,” said Richard Webby, a virologist at St. Jude’s Children’s Research Hospital in Memphis, Tennessee. “It’s pretty hard to explain some of these large infections and die off without having mammal-to-mammal spread.”

The strain has shown up in dozens of bird species, including some migrating species, which can spread it beyond the region, scientists told Reuters.

As climate change escalates, animals will be forced to move into new territories, mixing with one another in new ways and possibly boosting opportunities for the virus to further mutate.

“It’s a matter of time before you will detect the first South American strain in North America,” said Alonzo Alfaro-Nunez, a viral ecologist at University of Copenhagen.

Human risk

The growing concern has prompted the 35 countries in the Pan American Health Organisation (PAHO) to convene regional health experts and officials at a meeting this week in Rio de Janeiro.

The group plans to launch the world’s first regional commission to oversee bird flu monitoring and response efforts, a PAHO official told Reuters. This has not been previously reported.

Since the virus was first detected in Colombia in October 2022, there have been two known cases in humans on the continent, one each in Ecuador and Chile. Both came from exposure to infected birds.

While those patients survived, H5N1 bird flu is deadly to humans in roughly 60% of cases worldwide.

The World Health Organisation (WHO) is unlikely to raise the risk level for humans from the current “low” without evidence of human-to-human transmission or mutations adapted to human receptors, experts said.

Drugmakers, including GSK and Moderna, have said they are developing bird flu vaccines for humans, and have the capacity to produce hundreds of million so doses within months utilising production lines used for seasonal flu vaccines.

“We’re seeing [the virus] doing little evolutionary steps that are on the long-term moving towards a potential human infection,” said Ralph Vanstreels, a University of California, Davis researcher studying South American variants of H5N1.

Every year, Argentina’s Peninsula Valdes on the windswept Atlantic coast teems with densely packed elephant seals rearing pups.

Last November, Mr. Vanstreels came across a grim scene: hundreds of dead and rotting pups on the beach. Researchers estimate 17,400 pups died, nearly all born to the colony that year.

For each of those pups to have been infected by birds is highly unlikely, scientists said. Pups usually have contact only with their mothers, leading scientists to suspect this is how it spread.

Mr. Vanstreels is part of a group of scientists working to trace the virus’ genetic mutations in South America.

In a draft paper posted on the U.S. Centres for Disease Control and Prevention website, they analysed samples from sea lions, seals and birds from up the coast from Peninsula Valdes. Comparing the genomes from these samples with those collected in North America in 2022 and Asia earlier, the team identified nine new mutations.

The same mutations were found in samples collected in 2022 and 2023 in Chile and Peru, which were also hit by mass mortality of sea lions and birds.

“This is the first time this virus is so adapted to wildlife,” Mr. Vanstreels said. “Clearly something happened in Peru and in northern Chile where they acquired these new mutations.”

In the draft paper, researchers noted that the same mutations were present in one of the continent’s two human cases, a 53-year-old man who lived one block from the seashore where seabirds congregated.

Researchers said that case “highlights the potential threat posed by these viruses to public health.”

Regional response

With health officials and experts meeting in Rio this week, Latin American countries will be pressed to boost disease surveillance in the wild.

The region’s patchy data and limited resources has left scientists struggling to understand how the disease is spreading in the wild, with the number of cases likely much higher than reported. Some cases are not being sampled or lab-tested, scientists said.

Bolivia, for example, did not register a case in the wild last year, though the disease has been detected in surrounding countries, said Manuel Jose Sanchez Vazquez, epidemiology coordinator for PAHO’s veterinary health centre.

Managing the disease response can also be complex, Mr. Sanchez noted. Threats to humans are dealt with by public health officials, while threats to poultry or livestock fall to agriculture or veterinary authorities. In wild animals, the purview typically falls to environmental officials.

The new regional commission, expected to be announced on March 14, would aim to set standard protocols for monitoring, handling and reporting cases among various government agencies. It could also help in pooling laboratory resources, Mr. Sanchez said.

“We are worried and we are vigilant,” Sanchez said. “The more adaptation of the virus to mammals, the more likely it is that transmission to humans could happen.” (Reporting by Jake Spring; Editing by Katy Daigle and Bill Berkrot)

A skua stands on Deception Island, which is the Caldera of an active volcano in Antarctica, February 17, 2018.
| Photo Credit: Reuters

A deadly type of bird flu has been confirmed on the mainland of Antarctica for the first time, scientists said, a potential risk for the southern region’s huge penguin colonies.

“This discovery demonstrates for the first time that the Highly Pathogenic Avian Influenza virus has reached Antarctica despite the distance and natural barriers that separate it from other continents,” Spain’s Higher Council for Scientific Investigation (CSIC) said on Sunday.

The presence of the virus was confirmed on Saturday in samples of dead skua seabirds that were found by Argentine scientists near the Antarctic base Primavera, CSIC added.

The confirmed case on the Antarctic peninsula, coming after cases on islands nearby, including among gentoo penguins, highlights the risk to colonies in the region to the H5N1 avian flu that has decimated bird populations around the world in recent months.

“Analysis has conclusively shown that the birds were infected with the H5 subtype of avian influenza and at least one of the dead birds contained the highly pathogenic avian influenza virus,” CSIC said in a statement.

Argentina’s Antarctic Institute on Monday said that the South American country had worked with Spanish researchers to test samples from dead birds found earlier in the year near the Argentine base, which confirmed the presence of the virus.

Hundreds of thousands of penguins gather in tightly packed colonies on the Antarctic continent and nearby islands, which could enable the deadly virus to easily spread.

Data from the Scientific Committee on Antarctic Research also showed a now-confirmed case at the research base.

A deadly type of bird flu has been confirmed on the mainland of Antarctica for the first time, scientists said, a potential risk for the southern region’s huge penguin colonies.

“This discovery demonstrates for the first time that the Highly Pathogenic Avian Influenza virus has reached Antarctica despite the distance and natural barriers that separate it from other continents,” Argentina’s Higher Council for Scientific Investigation (CSIC) said on Sunday.

The presence of the virus was confirmed on Feb. 24 in samples of dead skua seabirds, which were found by Argentine scientists near the Antarctic base Primavera, CSIC added.

The confirmed case on the Antarctic peninsula, coming after cases on islands nearby, including among gentoo penguins, highlights the risk to colonies in the region to the H5N1 avian flu that has decimated bird populations around the world in recent months.

“Analysis has conclusively shown that the birds were infected with the H5 subtype of avian influenza and at least one of the dead birds contained the highly pathogenic avian influenza virus,” CSIC said in a statement.

Hundreds of thousands of penguins gather in tightly packed colonies on the Antarctic continent and nearby islands, which could enable the deadly virus to easily spread.

Data from the Scientific Committee on Antarctic Research also showed a now-confirmed case at the research base.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

A turkey stands in a barn, Aug. 10, 2015, on a turkey farm near Manson, Iowa. The U.S. Department of Agriculture reported that avian influenza (bird flu), which is deadly to commercial poultry, was confirmed in a flock of 47,300 turkeys in Jerauld County of South Dakota last Wednesday, Oct. 4, 2023, and at a farm with 141,800 birds in Sanpete County of Utah last Friday, Oct. 6.
| Photo Credit: AP

Scientists in Britain have found they can partially protect chickens from bird flu infections by editing their genes, signalling a new potential strategy to reduce the spread of the deadly virus.

Highly pathogenic avian influenza, known as bird flu, has spread to new corners of the globe since 2022, wiping out millions of poultry birds and sending egg and turkey prices soaring.

Experts warn that mutations could potentially threaten a human pandemic, though the current strain has not caused significant disease in people.

Researchers said they used the gene-editing tool CRISPR to make specific changes to a gene called ANP32 that is essential to support flu viruses inside chickens’ cells. CRISPR is a type of molecular “scissor” technology that scientists can use to edit DNA.

Also Read | Mammalian spread of H5N1 and its pandemic potential 

Flu viruses hijack proteins like ANP32 inside cells to help themselves replicate, and the edits in chickens were designed to stop the growth of bird flu.

Upticks in cases tend to occur during the spring and autumn migration of wild birds that transmit the virus, and the U.S. last week reported its first case in a commercial flock since April.

Experiments showed that almost all of the gene-edited chickens showed resistance to lower doses of a less lethal form of bird flu than the H5N1 strain that has circulated the globe recently, said Wendy Barclay, a flu expert and professor at the Imperial College of London.

When birds were exposed to much higher levels of the virus, though, about half of the gene-edited chickens had breakthrough infections, she said.

Also Read | Most avian flu outbreaks in India reported from post-monsoon to pre-summer season: study

“We can move toward making chickens resistant to the virus but we’re not there yet,” Barclay said. “We would need more edits – more robust edits – to really shut down the virus replication.”

The findings were published in Nature Communications on Tuesday.

Researchers now think that making three specific genetic changes to chickens’ cells will better protect birds. However, they have not bred chickens with three edits yet, said Helen Sang, who previously studied genetically modifying chickens against bird flu at the University of Edinburgh.

Sang said scientists found that genetic modification would not work well enough.

Unlike genetic modification, which introduces foreign genes, gene editing alters existing genes. The technology is considered to be less controversial than genetic modification and is more lightly regulated in some countries.

“The way forwards here is not to rely on single edits but to use a combination of them,” Barclay said.

France this month became the first country in the European Union to vaccinate poultry against the virus.

However, that strategy led the U.S. to impose trade restrictions on French poultry imports, citing a risk of introducing the virus into the country because vaccinated birds may not show signs of infection.