Opinion | H5N1 bird flu has infected a human – The Washington Post – The Washington Post

Since early 2022, a highly pathogenic strain of avian flu, H5N1, has been infecting wild aquatic birds and domestic poultry in the United States. More than 85 million birds in 48 states have died as a result of the virus or have been culled after exposure to infected birds.

This same strain has now spread to cows. Health officials have detected H5N1 in cattle across 16 herds in six states. And this month, the Centers for Disease Control and Prevention reported a case of bird flu in a dairy worker in Texas who likely contracted the virus from cattle.

This is an alarming situation that must be monitored closely. Livestock workers and owners of backyard flocks need to take extra precautions, and clinicians should be on the lookout for new human cases. Most Americans, though, should not be concerned about the risk of avian flu to them at this time.

Avian influenza is not new. The first description of it dates from the late 1800s. Like human flu viruses, there are multiple strains of bird flu. Some strains cause mild or no symptoms. Others are associated with mortality rates as high as 90 to 100 percent in domesticated bird species.

Many bird flu viruses originate in wild aquatic fowl and are then passed on to chickens, turkeys and other domesticated birds. While most transmission occurs among birds, some strains can cross over to infect mammals. The H5N1 strain has already been detected in more than 200 mammals in the United States.

That includes humans. In addition to the Texas dairy worker, an individual in Colorado working with poultry was diagnosed with H5N1 in 2022. The dairy workers only symptom was eye inflammation, and the poultry worker experienced fatigue. But prior cases from elsewhere in the world have resulted in pneumonia, multiple organ failure and death.

Indeed, the specter of severe illness is what makes avian flu a worrisome disease. The World Health Organization reports that 887 people globally have been infected with this strain over the past two decades. The mortality rate was 52 percent.

That is a terrifying number. Though there are approved H5N1-specific vaccines, it will take months to ramp up production. (The current seasonal flu vaccine probably does not prevent avian flu, though the CDC recommends it because it prevents people from contracting the regular flu at the same time.) There are antiviral treatments that should reduce the risk of hospitalization and death, but mortality could still be substantial if many people become infected.

Heres the reassuring part: Transmission among humans has, so far, been uncommon. Most people infected with bird flu worked closely with infected animals. Of those who contracted avian flu from other humans, most were living in the same household with a symptomatic person, resulting in close, prolonged and unprotected exposure. During the current H5N1 outbreaks, there has been no documented human-to-human transmission.

Of course, this could change. The more widespread the virus becomes among other mammalian species, the more it could acquire mutations that facilitate its spread among humans. Clinicians need to be on the lookout for people who work with animals and start experiencing symptoms. Scientists must continue tracking the spread of H5N1 in other species, and the federal government should ensure that a robust plan is in place should widespread vaccine distribution be needed.

For now, most people do not need to change their daily lives. Specifically, they do not need to stop drinking milk or eating chicken. Pasteurizing milk and cooking poultry kills pathogens, including the avian influenza viruses.

Those who have frequent contact with birds should take additional precautions. Bird flu is spread through direct contact with secretions from the animals mouth or nose, or through its feces. The virus can also be inhaled as well as transmitted from someone touching a contaminated surface and then their mouth, nose or eyes.

The CDC recommends that poultry workers, individuals who rehabilitate birds in sanctuaries and people with backyard flocks use eye protection and a well-fitting face mask if they have to handle sick birds. They should avoid touching their mouth, nose or eyes after contact with possibly contaminated objects. Hand-washing is a must, and workers should change clothes after handling birds. Hobbyists, meanwhile, should observe wild birds at a distance and especially stay away from birds that look sick or have died.

Finally, its worth remembering that avian flu is one of more than 200 diseases that are spread between animals and humans. Zoonotic diseases have been increasing with warming climates, urbanization and the destruction of natural habitats, which have all accelerated contact between humans and wild animals. Protecting humans from these diseases requires not only better surveillance and expedited vaccine research, but also environmental measures that safeguard biodiversity.

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Opinion | H5N1 bird flu has infected a human - The Washington Post - The Washington Post