The first human death from bird flu in the US has sparked concern, reminding many of the early days of COVID-19, CNN reports.
However, while both viruses can cause respiratory issues, there are significant differences between them. COVID-19 spread easily among humans from the outset, whereas H5N1 bird flu has primarily been an issue for animals. Moreover, scientists have studied H5N1 for decades, and the US has long been preparing for the potential of a new flu outbreak.
Still, H5N1 has recently displayed changes that warrant attention. Here’s a closer look at what this virus is, how it spreads, and its potential risks.
Avian influenza, or bird flu, refers to several influenza viruses that primarily infect birds. The current strain raising alarms in the US is H5N1, a highly pathogenic variant that often kills infected birds.
Although bird flu viruses mainly target birds, they can occasionally infect other animals, including humans. These human cases are rare and usually result from direct contact with infected animals rather than human-to-human transmission.
H5N1 is not new; it was first identified in geese in China in 1996. Since then, it has caused outbreaks in wild and farmed birds worldwide.
The virus re-emerged in North America in late 2021, and its ability to infect a broader range of species has raised concerns. In the current wave of infections, H5N1 has spread to over 48 species in at least 26 countries, including mammals like sea lions and dairy cows.
Most human infections occur through contact with infected animals or their droppings. For example:
- Farm Workers: Workers on poultry and dairy farms can be exposed to virus-laden dander, feathers, or milk.
- Backyard Bird Owners: People handling small bird flocks face risks if proper precautions aren’t taken.
Direct transmission from person to person has not been observed, and public health monitoring has not detected widespread human infections.
Scientists agree that for H5N1 to spark a pandemic, it would need to undergo significant genetic changes, enabling it to spread efficiently between humans.
Viruses like H5N1 evolve through:
- Genetic Mutation: Random changes during replication could make the virus better suited to infect human cells.
- Reassortment: When two viruses exchange genetic material, they can acquire new traits rapidly.
Although H5N1 has shown some signs of adaptation to humans, it remains relatively inefficient at infecting people compared to seasonal flu viruses.
The most common symptom in humans is conjunctivitis (red, inflamed eyes). Other symptoms include fever and respiratory issues, though these are less common.
Two severe cases in North America highlight the potential risks:
- A Canadian teenager developed respiratory and kidney failure but survived.
- A Louisiana resident over age 65, with underlying health conditions, recently died after exposure to infected birds.
Public health agencies, including the CDC, are closely monitoring infections and conducting contact tracing. Testing for H5N1 is now more accessible, with commercial labs like Quest Diagnostics offering diagnostic tests.
The current risk to the general public remains low, according to the CDC. Cooking poultry and dairy products to recommended temperatures also eliminates the virus, further reducing risks.
