Genetic Changes Found in U.S First Severe Bird Flu Case

Although Belize remains free of avian influenza, the U.S. is facing rising cases. A recent genetic analysis of the avian influenza, also known as the bird flu virus, found in a Louisiana patient has revealed mutations that may enable the virus to more easily bind to human respiratory cells. While the U.S. Centres for Disease Control and Prevention (CDC) has called these mutations concerning, it emphasised that the overall risk to the general public remains low.

According to reports, the Louisiana patient was hospitalised in critical condition after coming into contact with sick and dead birds in a backyard flock. This case marks the first severe instance of H5N1 bird flu in the U.S. in recent years.

Bird flu is a contagious disease that mainly affects birds but can rarely spread to humans. In humans, bird flu can cause symptoms like fever, muscle aches, sore throat, shortness of breath, runny nose, and headaches. In severe cases, it can lead to pneumonia, brain inflammation (encephalitis), diarrhoea, and trouble breathing. The virus spreads when a person comes into contact with infected birds, their bedding, or their droppings.

The CDC’s analysis, published this week, showed that the mutations detected in the virus were not present in the birds, suggesting that they likely developed during the patient’s illness. However, experts like Michael Osterholm, an infectious disease specialist at the University of Minnesota, stressed that while the virus may be adapting, it is not yet capable of spreading easily between people. “This is a key that sits in the lock, but it doesn’t open the door,” Osterholm said.

The CDC confirmed there has been no evidence of the virus spreading from the Louisiana patient to others. The CDC also noted that the mutations detected in the patient’s virus did not show signs of resistance to antiviral treatments or changes that would make the virus more adaptable to mammals. This means current treatments and vaccines, if needed, are still effective.

In 2024, the CDC has confirmed 65 human cases of H5N1 in the U.S. Of those, 39 were linked to dairy herds and 23 to poultry farms and culling operations. Two cases have unknown sources of exposure. The Louisiana patient is the only known case connected to backyard birds.

For now, the CDC says the risk to the general population remains low but stressed the importance of ongoing surveillance to monitor its changes.