Well-Being Prevention & Cures

What to know about the avian influenza outbreaks

The risk to humans is low unless there’s direct contact. Scientists are keeping an eye on how the viruses are circulating in wild bird populations.
Eighteen wheeler truck in background and large statue chicken in foreground
PALMYRA, WISCONSIN – MARCH 24: A truck drives out the entrance of the Cold Springs Eggs Farm where the presence of avian influenza was reported to be discovered, forcing the commercial egg producer to destroy nearly 3 million chickens on March 24, 2022 near Palmyra, Wisconsin. To control the spread of the virus, the U.S. Department of Agriculture has mandated testing of all poultry in a control area established around the infected farm before the birds or eggs can be sold or transported. The discovery of avian Influenza at the farm was the first case reported in Wisconsin, but it has already been reported on poultry farms in several Midwest states. Photo by Scott Olson/Getty Images

Story at a glance

  • Outbreaks of avian influenza have been reported among wild and domesticated birds since late 2021.

  • A handful of cases in humans have been detected in the U.S. and U.K.  

  • The risk to people is low, although scientists are concerned that wild birds are spreading it and dying from it.

Recent outbreaks of avian influenza in the U.S. and dozens of other countries have sickened wild and domesticated birds, leading to fears of economic impacts and risk of spreading to human beings. Here’s what we know. 

Avian influenza has been around for many years, with occasional new strains crossing over from wild birds to domesticated poultry. The influenza virus can be shared across species and transported by migrating birds. Pigs can also contract the virus, and occasionally humans will get infected through close contact with infected animals. 

One of the largest epidemics occurred in 2014-2015, with many more human cases worldwide than previous outbreaks. Avian influenza could infect people if exposed to infected animals but it typically is not easily transmitted from human to human. Scientists have warned for decades that if a new strain of the virus appears that is more easily transmissible among humans that it could lead to a pandemic. 

People who are infected may not show symptoms, but if they do it can include eye redness, upper respiratory illness, fever, fatigue and cough. In severe cases, patients may be admitted to the hospital. A study of human cases from past outbreaks found that there was persistent lung damage in some patients up to 12 months later. Mortality rates vary by strain. For example, one outbreak in 2013 in China resulted 131 cases and 36 deaths, with a mortality rate of about 27 percent, according to a study published in Pathogens and Public Health. The same study cites that for the highly pathogenic virus H5N1 during previous outbreaks was as high as 60 percent.  

What’s happening now 

The recent outbreaks have affected wild birds and poultry flocks in the U.S., U.K., Israel and dozens of other countries. A few different strains are circulating, which is normal, including strains of highly pathogenic avian influenza. 

As of today, the Centers for Disease Control and Prevention estimates that more than 37 million poultry birds in 36 states have been affected by the outbreak. When avian influenza is detected, whole flocks of poultry are culled to try to prevent further spread of the disease. Especially in settings where the birds would be housed in close quarters, the virus can move rapidly through a flock. 

There has been one case of avian influenza in a human in Colorado, detected in April. The first case in a person internationally was detected in Dec. 2021 in the U.K. 

How this relates to the economy, inflation and food insecurity 

With flocks needing to be culled for health and safety reasons, this could also lead to a shortage in supply. The shortage can affect the prices of chicken and eggs, but also downstream products like processed eggs in liquid or powder form. 

If prices increase, this could exacerbate the food insecure conditions that many people are already experiencing, in part due to the pandemic. Food banks have recently reported that demand has again increased, on top of inflation and supply chain issues. 

How concerned should we be? 

A recent study focused on the diversity of bird species and how that may affect evolution of the avian influenza viruses. The researchers suggest that wild ducks, geese, swans and gulls have varying roles in virus evolution based on how the species move geographically and which subtypes of the virus they harbor. Avian influenza viruses are known to mutate and evolve, so it is not surprising that new strains emerge periodically. 

Some scientists are concerned this time around because it seems many wild birds are dying in the various local outbreaks around the world. Although wild birds may be infected by various avian influenza viruses, they typically do not die from it as often as domesticated birds do. The fact that many are dying and also spreading the viruses through migration means that surveillance will be key to keep track of what’s happening in both wild and domesticated birds. 

The risk to humans remains low and the people who are at most risk are those who handle poultry and work in livestock environments. “If you see a bird that seems to be sick—it can’t stand up, looks off balance, or isn’t aware of its surroundings—we recommend first calling your local animal control officer or a wildlife rehabilitator for assistance,” says Maureen Murray, one of the study authors who is a clinical associate professor at Cummings School, in a press release. “But if you must handle it yourself, we recommend wearing at minimum a three-ply face mask, or a more protective mask if available, such as an N95. Gloves are also a good idea, but if they’re not available, wash your hands really, really well afterward.”