Irene Wright | The Charlotte Observer (TNS)
As a new virus takes center stage at the heart of a global outbreak, it’s easy to get flashbacks of March 2020.
Now more than four years after the world was rocked by a pandemic, H5N1, or avian or bird flu, has exploded in bird and livestock populations, and at least one human case has been confirmed by health officials.
This isn’t the first time.
There have been major outbreaks around the world in the recent past, including four from 2014 to 2017, according to the Centers for Disease Control and Prevention.
So what makes this time different, and at what point should you be concerned?
Here are five things you should know about bird flu.
What type of virus is it and how does it spread?
H5N1 comes from a group of four flu, or influenza, viruses: A, B, C and D. The strain called bird flu is an influenza A virus and gets its name because wild birds such as gulls, ducks geese and other waterfowl act as hosts for the virus.
Avian influenza is considered either low pathogenic (LPAI) or highly pathogenic (HPAI), determined by how serious the infection is, according to the CDC.
Most avian influenza cases are low pathogenic, causing only a few infections. Sometimes, however, the LPAI can mutate and become a HPAI.
Highly pathogenic avian influenza in chickens, for example, impacts internal organs and has a 90-100% mortality rate in just 48 hours after infection, according to the CDC.
Both LPAI and HPAI can spread rapidly through bird populations, and both have been known to infect species other than birds.
The current strain is considered highly pathogenic.
H5N1 is spread from animal to animal through saliva, mucus and feces, or through the contact of bodily fluids, the CDC says. It can also be spread in water droplets then come in contact with eyes, the nose or mouth.
Can humans get bird flu?
Yes, cases of bird flu have been reported in humans, but they are incredibly rare and usually associated with mild symptoms.
In the United States, only two human cases have been reported in recent years, one in 2022, and one this year from a dairy worker in Texas, according to health officials.
On April 1, the Texas Department of State Health Services announced a worker had conjunctivitis, or pink eye, a common symptom of H5N1 in humans, and they later tested positive for the virus.
This has been the only confirmed human case in the U.S. as part of the most recent outbreak.
In the past, 1,500 people in China tested positive for H7N9, another strain of low pathogenic avian influenza, between 2013 and 2017, and the cases spread to Hong Kong, Macau, Malaysia, Taiwan and Canada, according to the CDC. Some included in the outbreak had no symptoms at all, but others experienced upper respiratory tract infections leading to hospitalizations, 40% of which were fatal.
Various smaller outbreaks and cases have been reported over the past few decades.
What animals have been infected with bird flu?
According to data published by the CDC from the first week of May, 48 states have reported bird flu outbreaks in poultry, which includes chickens and other domesticated birds.
More than 90 million poultry birds have been impacted, as well as 9,349 wild birds across 50 jurisdictions.
Infections have also spread to dairy cattle across 9 states, infecting 36 herds, CDC data shows. This was likely caused by birds flying over the herds, and not from direct contact, health officials said.
Outside of agriculture, there have been reported H5N1 cases in 19 mammal species across the U.S. as of May 7, according to the U.S. Department of Agriculture.
Skunks and red foxes have reported the most cases, and the cases are predominantly in the northern half of the U.S. and Alaska, data shows.
Are animal products safe to eat?
Bird flu cases are mainly restricted to commercial poultry and cattle, data shows.
Eggs, meat, cheese and milk that are sold commercially are safe to eat, according to Harvard Medical School.
Fragments of bird flu, which is not the same as active live virus, have been found in about 20% of the commercial milk supply, Harvard says, but there is no indication that the fragments could infect humans.
Could bird flu become a human pandemic?
The short answer is that it is too soon to tell. Concern from health officials is low, but growing as the virus continues to spread.
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“While the current public health risk is low, CDC is watching the situation carefully and working with states to monitor people with animal exposures,” the agency said.
The spread of the virus in cattle is more likely to increase human exposure as dairy workers come in closer contact with the animals, Time Magazine reports, but unlike COVID-19 that spreads easily from person to person, H5N1 is not as transmissible.
“The spread of bird flu viruses from one infected person to a close contact is very rare, and when it has happened, it has only spread to a few people. However, because of the possibility that bird flu viruses could change and gain the ability to spread easily between people, monitoring for human infection and person-to-person spread is extremely important for public health,” the CDC says.
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