Bird Flu: Is There Cause for Concern?

Bird flu, caused by the H5N1 strain of the influenza virus, is widespread in both domestic and wild birds all over the world, causing a significant number of bird deaths. The virus has already jumped to mammals, including bears, dolphins, foxes, mink, otters, sea lions and seals. But it hasn’t crossed over commonly to humans—at least, not yet.

Says Dr. Roy Gulick, an Attending Physician, Rochelle Belfer Professor in Medicine and Chief of the Division of Infectious Diseases at Weill Cornell Medicine/New York Presbyterian Hospital, bird flu rarely infects humans, and when it does, it is almost always through direct human contact with infected birds.

At this point, he says, we haven’t seen human-to-human transmission of the bird flu virus. However, zoonotic diseases—those that spill over from animals to humans—have been on the rise in recent decades, traceable in some cases to climate change and the encroachment of humans into animal habitats.

Among these diseases are several coronaviruses, including SARS (severe acute respiratory syndrome), MERS (Middle Eastern respiratory syndrome) and, of course, SARS-CoV-2, the virus that causes COVID-19.

While SARS and MERS haven’t risen to anything close to pandemic status, the World Health Organization (WHO) has recorded close to 7 million COVID-19 deaths so far—a number most experts believe to be underestimated.

Does bird flu pose a significant danger to humans?

Recently, public health experts have been trying to assess the risk of a new pandemic, one caused by bird flu.

Bird flu has already killed a significant number of chickens in the U.S., accounting for the sharp rise in the price of eggs. But it may pose a threat to humans down the road that’s far more serious than rising prices.

“Bird flu is so widespread among birds that there is a significant amount of virus. That means it could mutate,” Dr. Gulick says. “Human contact with birds could allow a mutated virus to infect humans more easily and could facilitate human-to-human transmission. Because we may not have natural immunity to this virus, the infection could then spread rapidly among us.”

How can our city and region prepare for the possibility of a bird flu epidemic?

We should continue to follow this evolving situation closely, he says. “Government officials around the world are investigating any human cases and their contacts. People who have direct contact with domestic or wild birds and wild animals should use personal protective equipment, like masks and gloves. Current efforts to combat a possible bird flu pandemic include massive vaccination of birds and the development, testing and eventual roll-out of additional bird flu vaccines for people.”

According to the Centers for Disease Control (CDC), that effort is well underway. The federal government maintains a stockpile of vaccines against the two most prevalent bird flu viruses: H5N1, which is responsible for the current outbreak, and H7N9. These vaccines could be used if similar viruses were to begin spreading easily from human to human. As well, several vaccine manufacturers are developing and testing bird flu vaccines for humans and could make hundreds of millions of vaccine doses, if needed.

Prevention: A shared responsibility

The best way to prevent bird flu is to avoid sources of exposure whenever possible. Although people rarely get it, infections can occur when enough virus gets into a person’s eyes, nose or mouth, or when it’s inhaled.

Bird flu infections in people mostly happen after close, unprotected contact—without gloves or other protective wear—with infected birds, and that person then touches their mouth, nose or eyes.

Infectious disease specialists at Weill Cornell Medicine will continue to follow this story as it develops across the globe and in the New York Metropolitan Area.

If you have any concerns about infectious diseases, whether actual or potential, get in touch with your doctor by scheduling an appointment.