What is H5N1 Virus? How It Spreads to Humans

The H5N1 bird flu virus has affected all 50 states in the US. Since March 2024, the virus has infected more than 1,000 dairy herds across the US, with more than 70 human infections. The Global Virus Network (GVN) has warned about the possibility of a fresh pandemic in the US, as the virus's circulation in mammals can increase the risk of mutations that could enable human-to-human transmission.

The current outbreak highlights the urgency of enhanced surveillance, standardised testing, and vaccination strategies for both animals and farm workers.

What is H5N1 bird flu?

Avian influenza A(H5N1) is a subtype of influenza virus that causes a highly infectious respiratory disease in birds and mammals. It can also infect humans. According to the World Health Organization, infections in humans can cause severe disease with a high mortality rate.

What are the symptoms of H5N1?

The H5N1 influenza virus can cause mild to severe symptoms in infected individuals. It can also be fatal in some cases. Symptoms reported have primarily been respiratory, but some may experience non-respiratory symptoms and conjunctivitis. Some common symptoms include:

• Fever
• Cough
• Sore throat
• Muscle ache
• Uneasiness

H5N1 virus has also been detected in individuals without symptoms.

How does it spread to humans?

The H5N1 virus does not seem to transmit from one person to another. There have been no reports of ongoing human-to-human transmission. According to WHO, the human cases detected thus far are mostly linked to close contact with infected birds (both live and dead), other animals, and contaminated environments.

Could the US outbreak spark a new Pandemic?

The Global Virus Network (GVN) has warned that there is an increased risk of mutations that are capable of human-to-human transmission.

"Understanding the current landscape of H5N1 infections is critical for effective prevention and response," said Sten H Vermund, MD, PhD, chief medical officer of the GVN and dean of the USF Health College of Public Health at the University of South Florida, USA. "The virus' ability to infect both animals and humans, combined with recent genetic changes, underscores the importance of proactive surveillance and rapid response measures."

How to stay safe during an outbreak

• Avoid consumption of raw, incompletely cooked meat and eggs from areas experiencing outbreaks.
• Avoid contact with sick or infected birds and animals.
• WHO advises to avoid raw milk and recommends consumption of pasteurized milk. If pasteurized milk isn't available, heating raw milk until it boils can also make it safer for consumption.
• Wash hands with soap and water after handling poultry or visiting high-risk areas.
• Do not ignore the symptoms and seek medical help if needed.

Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.