Bird flu continues to pose a low risk to the general public according to the Centers for Disease Control and Prevention.
It is rare for humans to get bird flu and currently, most cases of bird flu in people around the globe are linked to direct contact with an infected animal ― mostly birds.
But scientists are paying close attention to how the virus is changing and are on high alert for any changes in the bird flu virus that might enable it to spread more easily among people.
Since April, there have been seven human cases among dairy workers.
Here are some bird flu basics:
Q: What is bird flu?
A: Bird flu is a group of viruses that primarily infects birds. It is a respiratory virus that infects the lungs and breathing passages.
Q: Can people catch bird flu?
Yes. Bird flu does not usually infect people, but there have been some people who have caught the virus through exposure to sick or dead animals.
Q: How long has bird flu been around?
Bird flu was first detected in 1996 among birds in China, according to the CDC. One year later, an outbreak in Hong Kong resulted in 18 human cases, including six deaths, after people were infected directly by birds.
In late 2021, a version of the virus arrived on the shores of the U.S. and was found in wild birds. Since February 2022, the virus has caused outbreaks in commercially raised poultry, including chickens and turkeys. That has led to the deaths or the culling of more than 90 million birds across the country, according to the USDA.
Credit: Charlie Neibergall
Credit: Charlie Neibergall
Q: So why are scientists so worried about bird flu?
Bird flu has had a fatality rate of about 50% of the known cases in humans, according to the CDC.
There have been 861 human cases — and 455 deaths — reported from 17 countries from November 2003 to May 2019, according to the CDC.
CDC health experts say because people have little immunity to this virus, it could cause a pandemic if the virus changes so that it can spread easily from person to person.
So far, the virus has not changed in a way that allows it to spread easily from one person to another. Scientists say it’s possible that will never happen.
Credit: Centers for Disease Control & Pr
Credit: Centers for Disease Control & Pr
Q: What are the symptoms of bird flu in humans?
Bird flu is a respiratory virus. In humans, bird flu may cause illnesses similar to influenza (the flu) with fever, cough, sore throat, runny nose and muscle aches. It can cause pneumonia and breathing problems, according to the CDC.
Some people report no symptoms or mild symptoms such as eye redness.
Q: How do people catch it from animals?
People can get infected with bird flu by direct exposure to sick birds and dairy cattle.
Infected birds have avian flu virus in their saliva, mucous, and feces. It can potentially spread to a person who touches a sick animal or contaminated surface and then touches their eyes, nose or mouth. The virus can also potentially be spread when the virus is inhaled from droplets or dust in the air.
Those who work closely with sick birds or other sick animals without personal protective equipment such as masks and eye protection face a higher risk of infection.
Q: How did cows get it?
It is not entirely clear how dairy cows in the U.S. were first infected. One likely route is infected birds, which shed the virus in their feces, saliva and other secretions, contaminating cows’ food or water.
The virus is believed to be spreading directly from cow to cow or through contaminated dairy equipment.
It also appears to be causing relatively mild illness in cows.
Q: How does bird flu spread person to person?
The reported cases of person-to-person spread are extremely rare globally, and only involve transmission from a sick person to a close family member or caregiver.
There has never been a confirmed person-to-person transmission of bird flu in the U.S.
Q: How many people in the U.S. have had bird flu?
So far this year, there have been 61 human bird flu infections reported in nine states, more than half of them in California. The cases are primarily in farm workers who have had contact with infected cattle or chicken flocks.
Many of the human cases reported mild symptoms of a viral infection along with eye redness known as conjunctivitis. The CDC reported on Dec. 13 a patient was hospitalized with a the first severe case of bird flu in Louisiana, marking first instance of severe illness linked to the virus in the United States.
The first human case in the U.S. occurred in Colorado in 2022 in a poultry worker. That worker recovered after experiencing fatigue.
Editor’s Note: This story has been updated to reflect news reported on Dec. 18.
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