Four Things to Know About Bird Flu

Avian Influenza, more commonly known as bird flu, has been making headlines.

Different from the seasonal influenza virus currently affecting millions of people, bird flu is a respiratory disease that primarily infects birds, but can also infect other animals and more rarely, humans. 

In January, an older Louisiana resident became the first person to die from bird flu in the U.S. 

Closer to home, state environmental and public health officials now consider avian influenza widespread among wild birds in Massachusetts, and it is the suspected cause of death for dozens of waterfowl – geese, swans and ducks – in Plymouth last month.  

To learn more about the bird flu and the potential risk to animals and humans, we interviewed South Shore Health’s Director of Infectious Diseases, Todd Ellerin, MD. 

What is bird flu and how does it spread?

Avian influenza, also known as H5N1 bird flu is a respiratory disease caused by influenza A viruses, that mostly affects birds. 

In the past three years, we have seen avian influenza become the worst animal pandemic in U.S. history.

While wild birds and poultry are most susceptible to the virus, other animals including cows, pigs and mammals that scavenge on birds, like foxes can also be infected.

While it is rare, people in close contact with infected animals, including farmers, poultry workers and those who respond to bird flu outbreaks can contract the virus. 

Avian influenza is spread through the saliva, nasal secretions and feces of infected birds. Other birds and animals can be infected by coming in contact with the virus as it is shed, or with surfaces contaminated with virus from infected birds.

How serious a risk is the bird flu for people? 

The risk to public health remains low and there has been no person-to-person transmission of bird flu reported. But the Centers for Disease Control and Prevention (CDC) continues to monitor avian influenza activity in people through its flu surveillance systems.

Bird flu outbreaks in poultry and dairy cows in the U.S. have recently resulted in several human cases among dairy and poultry workers. 

The total number of human bird flu cases in the U.S. is 68, with most of the cases (64) involving people who work with dairy herds, on poultry farms and in poultry culling operations due to an outbreak. 

People can be infected with bird flu when the virus gets into their eyes, nose, or mouth, or is inhaled. Infection can also occur if a person touches something contaminated with the virus and then touches their eyes, nose or mouth. 

Most infections in people have occurred after close and prolonged unprotected contact with infected birds, which is why the CDC recommends that those in contact with sick or dead wild birds, poultry, or other animals wear personal protective equipment (PPE), including gloves and masks.

Most human cases of avian influenza have been mild, with only one severe case resulting in the death of an older Louisiana resident who had other chronic health conditions. 

Bird flu symptoms in people can include conjunctivitis (eye infection) and upper respiratory symptoms – cough, sore throat, runny nose or congestion – fever, body aches and fatigue. Pneumonia can occur in severe cases of avian influenza.

As with seasonal influenza, antiviral drugs such as Oseltamivir (Tamiflu) are the recommended treatment for people with suspected or confirmed bird flu, and should be taken within 48 hours of the start of symptoms. 

What’s being done to control the bird flu epidemic

Given how rapidly avian influenza spreads and how strong a foothold it has in diverse animal populations, containing the virus – despite best efforts – will be challenging.

The CDC continues to focus on surveillance, human monitoring and developing public guidance and studying avian influenza virus for genetic changes that could increase the risk to public health.  

Surveillance of flocks near or linked to an infected flock, and quarantine of exposed flocks with culling if disease is detected, are current methods being used to try to contain bird flu. This has resulted in the culling of many millions of chickens in the past few years, leading to a decrease in egg production and higher egg prices at the grocery store. 

The time is now to ensure measures are in place to protect people from avian influenza. This entails widespread testing for early detection, and enhanced communication about animals that test positive for bird flu so that isolation, containment, and testing of other animals in close contact can be done. 

Biosecurity measures, including fencing should be used to keep wild birds away from commercial poultry flocks and prevent chickens from accessing water sources where wild birds congregate.

Dairy farmers, poultry workers and others in direct contact with potentially infected animals, should wear enhanced PPE to protect against bird flu. 

People should avoid contact with sick or dead wild birds, poultry or other animals, but if they become sick after exposure to infected animals, they should report the illness to their local or state health department and speak to their health care provider about bird flu testing and antiviral treatments to manage symptoms.  

Sick birds and unusual bird or other animal deaths should be reported by calling the USDA’s toll free number at 866-536-7593.  Massachusetts residents can make reports to the Division of Animal Health at 617-626-1795 or through this online reporting form. Five or more dead wild birds found in one location should be reported to the Massachusetts Division of Fisheries and Wildlife using the online form found at mass.gov/reportbirds.

We also need to determine how best to test and use the avian influenza vaccines the CDC is developing to help protect people and animals from severe illness from bird flu.

Should we be concerned about a bird flu pandemic for humans?

We are not at the beginning of a bird flu epidemic in humans, yet. There has been no human-to-human transmission of the virus in the U.S. That being said, there are some concerning signs we need to keep a close eye on.

Bird flu outbreaks in cows have affected 968 dairy herds in 16 states so far. The longer bird flu circulates in animals, the more likely humans are to become infected and the more selective advantage the virus has to find mutations enabling it to thrive in humans.  

In addition to poultry and cows, bird flu has been reported in at least one pig. That may not seem like a big deal, but a pig can act as a mixing vessel and can harbor both human and avian influenza strains. If these two viruses were to infect the same cell, they could recombine, swapping genetic material that could eventually lead to bird flu strains more capable of infecting humans and allowing human-to-human transmission.  This scenario worries us with respect to pandemic potential. 

Finally, two recent severe human cases of avian influenza – in a teenage girl from British Columbia, who is recovering and in the elderly adult from Louisiana, who died from the virus -- similar genetic mutations were seen, suggesting viral evolution that may allow bird flu attach to our upper respiratory tract and have a selective advantage to spread among humans.

While we are not currently facing a bird flu human pandemic, we need to do everything we can to prevent it and to be prepared if or when it occurs.     

Todd B. Ellerin, MD is Director of Infectious Disease at South Shore Health.