Health officials are raising alarms after new mutations of the bird flu virus (H5N1) were discovered in a patient from Louisiana.
These changes have sparked concerns about the virus potentially evolving to spread more easily among humans. Here’s what you need to know about the situation, its implications, and the steps being taken to monitor and prevent further spread.
What happened?
In December 2024, the Centres for Disease Control and Prevention (CDC) reported that a Louisiana patient hospitalised with severe respiratory illness was infected with a mutated strain of the H5N1 virus.
According to Fox 13, this marks the first severe human case of H5N1 in the US this year. Genetic analysis revealed rare mutations in the virus’s hemagglutinin (HA) gene, which plays a critical role in attaching to human cells.
The mutations detected in the Louisiana patient were not found in samples from the infected poultry on their property, suggesting these changes emerged as the virus replicated in the patient, as reported by the CDC.
Why are these mutations concerning?
The identified mutations may increase the virus’s ability to bind to receptors in the human upper respiratory tract, which is a key factor for human-to-human transmission. However, as per The Guardian, these changes were present in only a small proportion of the virus population, and there is no evidence of person-to-person spread in this case.
A similar mutation was observed in a case in British Columbia earlier this year, highlighting a pattern that scientists are closely monitoring.
How is bird flu spreading?
Since March 2024, the US has reported at least 65 human cases of bird flu. Most infections occur in people exposed to infected poultry or dairy cows. The Louisiana case involved contact with sick and dead birds, according to Fox 13.
The H5N1 virus has been circulating in two primary genotypes: D1.1, linked to wild birds and poultry, and B3.13, found predominantly in dairy cows. The Louisiana case was caused by the D1.1 genotype, which is more commonly associated with bird infections, as per CDC data.
What are the symptoms?
The CDC lists common bird flu symptoms as:
- Muscle aches
- Fever
- Severe respiratory distress in critical cases
Is the public at risk?
Health officials, including the CDC, emphasise that the risk to the general public remains low. However, those working closely with poultry or livestock, as well as individuals consuming raw milk from infected animals, may face higher risks.
California governor Gavin Newsom declared a state of emergency in December due to rising cases in the state, underscoring the need for vigilance.
What’s being done?
Efforts to monitor and contain the outbreak include:
- Genomic surveillance: The CDC is collaborating with state health departments to analyze viral samples and track mutations.
- Preventive measures: Public health officials are urging people to avoid contact with sick animals and to cook poultry products thoroughly.
- Vaccine readiness: Existing vaccine candidates are being reviewed for potential deployment, according to CDC.
The Bigger picture
According to The Guardian, experts like Dr Angela Rasmussen warn that the increasing number of human infections globally provides the virus more opportunities to evolve. “We don’t know what combination of mutations could lead to a pandemic H5N1 virus,” she noted.
While no human-to-human transmission has been documented in the Louisiana case, researchers remain cautious. Scott Hensley, a microbiologist from the University of Pennsylvania, stated that mutations like those observed are a prerequisite for transmissibility but may not be sufficient on their own.
The situation with bird flu mutations highlights the importance of continued vigilance. Public health officials are monitoring developments closely, emphasizing preventive measures to reduce exposure risks.
