HEALTH

What the latest bird flu outbreak could mean for humans

A dangerous and contagious bird flu continues to spread through poultry farms, wild birds, and now mammal populations.
There’s still no sign the virus is capable of spreading between humans, but experts are watching the outbreak closely.
“The recent spillover to mammals needs to be monitored closely,” World Health Organization director-general Dr Tedros Adhanom Ghebreyesus said during a press briefing.
“For the moment, WHO assesses the risk to humans as low.”

What is bird flu?
Avian influenza is a disease caused by influenza A viruses that spread widely among wild birds, particularly aquatic birds, birds of prey and waterfowl, but also domestic birds such as poultry.
In the United States, highly pathogenic avian influenza has been detected in about 6,000 wild birds and affected more than 58 million commercial poultry and backyard flocks since the start of 2022, according to data from the Centers for Disease Control and Prevention.
“It’s been the most serious outbreak for birds that we’ve had in the US of these highly pathogenic avian influenza viruses in recent memory,” said Nicole Nemeth, an associate professor of pathology and head of the wildlife research and diagnostic service at the Southeastern Cooperative Wildlife Disease Study at the University of Georgia.
According to the World Organization for Animal Health, avian influenza viruses can survive for long periods in cold temperatures on surfaces such as farm equipment, which allows them to spread from farm to farm.

What is causing this bird flu outbreak?
This particular outbreak is caused by the H5N1 bird flu virus, which was first discovered in China in 1996.
In 2021, a new variant of that virus emerged and started spreading around the world.
The virus started infecting chickens on poultry farms in the United States in February 2022.

What is different about this outbreak?
The size, range, and number of species affected by this outbreak is unprecedented, says Nichola Hill, a virologist at the University of Massachusetts Boston.
This is the deadliest bird flu outbreak in US history — nearly 60 million poultry have been affected.
Wild birds in all 50 states have the virus.
“It’s never really been seen in this number of different wild species before,” Hill says.
It’s also infecting mammals: skunks, bears, seals, foxes, dolphins, and animals of other species are showing up with the virus.
“That’s not really how bird flu should behave,” she says.
Most troubling is that the virus appeared on a mink farm where it seems to have spread between minks – not just from birds to individual minks.
That type of mammal-to-mammal spread is new. “We hadn’t seen that before,” Hill says.

Is there a risk to people?
Mammal-to-mammal spread is concerning, but it doesn’t automatically mean that the virus is going to significantly affect human populations.
People can get sick from bird flu, but cases are still rare.
They’re usually seen in people who work closely with birds.
One person in the United States has been infected with the virus during this current outbreak, and that person was responsible for culling sick poultry.
Right now, even though the virus may be evolving to infect more mammals, it hasn’t mutated in a way that would help it infect humans easier.
“It still isn’t hitting on that magic combination of mutations that are necessary to unlock efficient human transmission,” Hill says.
But it’s still important to watch and try to contain H5N1 spread in other animal species, because every time it adapts to a new host, there’s a chance those mutations could happen.
“We’re rolling the dice every time,” she says.
The Centers for Disease Control and Prevention says people should avoid contact with wild birds, and that people who work with poultry should take precautions like wearing gloves and masks.

How does bird flu affect humans?
It is rare, but humans can become infected with bird flu if they come into close contact with infected birds — whether the birds are dead or alive — or with surfaces that may have been contaminated by an infected bird’s saliva or feces.
Although the virus has been detected in wild mammals such as red foxes, raccoons, opossums and skunks – probably from eating infected wild birds – experts said the virus poses a low risk to humans.
In fact, since the start of the current outbreak, only one human case has been reported in the United States.
People who work closely with infected poultry are at an increased risk of becoming infected.
Infections could range from mild cases such as conjunctivitis — an eye infection that could occur after handling contaminated material and then touching the eyes — to more serious but rare respiratory infections, experts said.
The virus typically doesn’t infect the human respiratory tract, because humans don’t have the receptors in their throats, noses or upper respiratory tracts that are susceptible to the current bird flu strain.
A person would need to breathe in a large amount of the virus — by sweeping up and inhaling infected fecal matter deep into the lungs, for example — to develop a respiratory infection from the virus, said William Schaffner, a professor of infectious diseases and preventive medicine at Vanderbilt University.
“In those circumstances, the virus can initiate an infection in an occasional human and quickly develop into influenza pneumonia,” he said, and then “the fatality rate is very high.”
Human-to-human transmission of the virus is very rare, Schaffner said.
“If that happens, that human being is usually a very close caregiver of the sick person,” he said.

What are the symptoms of bird flu in humans?
Some people who are infected may not experience symptoms, according to the CDC. Others may have mild symptoms such as conjunctivitis or flu-like symptoms – fever, cough, sore throat, body aches, headaches, fatigue and, in more serious cases involving pneumonia, trouble breathing.
The symptoms of bird flu depend on the strain of the virus with which each person becomes infected. The strains that have caused most of the human infections in the last 25 years are H5N1 and H7N9, the CDC said.
Bird flu infection is diagnosed in a lab, usually by swabbing someone’s nose and throat.

How is it treated?
People who contract bird flu are typically treated with supportive care and, in serious cases, with ventilators to help them breathe. There are also antiviral medications that are effective at treating the current strains, Schaffner said.

Is there a bird flu vaccine for humans?
Yes. Federal authorities have vaccines against A(H5N1) and A(H7N9) bird flu viruses that could be used if these viruses were to start spreading among the human population, the CDC said. – Agencies

To mask or not to mask? Three Covid experts weigh in

THERE are still hundreds of thousands of Coronavirus (Covid-19) cases reported in the US each week, along with a few thousand deaths related to Covid-19.
But with mask mandates a thing of the past and the national emergency health declaration that will expire in May, we are in a new phase of the pandemic.
Life looks a little more normal here in the US than it did a few years ago, but decisions on how to deal with the virus aren’t over yet.
China had a huge increase in cases last month after abandoning its zero Covid policy, and another variant prompted renewed recommendations in some airports.
Researchers estimate that more than 65 million people are struggling with the effects of Covid – a disease we still have to learn about.
However, masking requirements are being lifted in places like Spain and Germany.
Wondering if and when you should still be masking up? NPR asked some experts.
Dr William Schaffner, a professor of infectious diseases at Vanderbilt University Medical Center, Dr Monica Gandhi, an infectious disease expert at the University of California, San Francisco, and Dr Bob Wachter, chair of the department of medicine at the same university all weighed in.

If you’re high risk, you should still be careful
Dr Schaffner says he and his wife are still playing it conservatively.
He cautions people to stay “careful, not carefree”.
As they are older, they are at higher risk of serious illness if they catch the virus.
They also care for a family member who is undergoing chemotherapy.
“Older persons, people of any age who have a serious underlying illness, heart disease, lung disease, diabetes, if you’re immune compromised,” Schaffner said, “keep wearing that mask”.

Consider masks in crowded, poorly ventilated places
Dr Wachter plays it a little more by ear.
“I have come to calibrate my mask wearing based on my best educated guess as to the possibility that someone has Covid and also how important is it for me to do the thing without a mask,” Wachter says.
While he’s no longer concerned about dying or serious illness, the virus can still knock you out.
Wachter watched firsthand as his wife recovered from a bout of long Covid-19.
He evaluates it case by case.
A small gathering where everyone is vaccinated and windows open may not require one.
But sitting on an airplane or in a large, crowded theater might be a good idea to do one.
“Those places, I’m wearing a mask now, and I suspect I will wear a mask forever,” Wachter said.
“Forever’s a long time. But the threat of Covid now, I think, is probably not all that different from it’ll be a year from now or five years from now.”

Vaccines have provided powerful protection
On the other hand, Dr Gandhi has leaned into the value of vaccines over masks.
“They’re really powerful in terms of what they were designed to do, which is to prevent severe disease,” Gandhi said.
“This is really the time at which you can say, ‘Oh, we have a lot of population immunity in our country.’”
Most Americans now have hybrid immunity, a combination of immunity from vaccines and catching the virus naturally, which is particularly strong. Gandhi feels comfortable going without a mask on most of the time.
Keep assessing your own risk and comfort level

All three experts agree it’s a matter of weighing personal risks.
“Lots of people are very cautious,” Gandhi said.
“Still, they’re happy with their vaccine and feel that they’re done worrying about it after vaccination. Everyone’s just going to have their own personal biases around that.”
Experts do not always agree on what to do.
“I don’t think it has a moral dimension,” Wachter says.
“I think we’re sort of past the time when any of the choices here are really bad choices.”
And Schaffner found that this winter there were other benefits to masking and social distancing – like avoiding RSV and flu bouts.
“We have shown that these things are really effective in reducing risk in a population,” he said. – NPR