Why in News ? 

A Louisiana resident, aged over 65 with pre-existing health conditions, has died from H5N1 bird flu following exposure to infected birds. This incident represents the first human fatality in the United States attributed to the virus in 2025. 

What is H5N1 Bird Flu? 

• H5N1, or avian influenza A(H5N1), is a highly pathogenic virus primarily affecting birds but capable of infecting mammals. 
• It originated in China in 1996 and rapidly evolved into a highly pathogenic strain. 
• Since 2020, it has spread across Europe, Asia, Africa, North and South America, and Antarctica. 
• India reported its first outbreak in Maharashtra and Gujarat in 2015. 

Impact on Animals 

• Wild birds, including endangered species like California condors, have been severely affected. 
• Chickens were the primary species affected in earlier outbreaks. 
• Marine mammals, such as sea lions and dolphins, have experienced mass deaths, especially in Chile and Peru. 
• Mammals like foxes, pumas, bears (North America), and farmed minks (Spain, Finland) have also been infected. 

Human Risk and Spread Factors 

• Human infection with H5N1 is rare and typically occurs through contact with infected birds. 
• Climate change may increase the virus's spread by altering bird behavior and interactions among species. 

WHO Risk Assessment 

• The virus does not easily infect humans, but sporadic cases linked to poultry exposure occur. 
• Human-to-human transmission is rare but possible, especially in regions with endemic poultry outbreaks. 
• WHO considers the overall risk to the general population low but stresses the need for ongoing surveillance and risk management. 

Preventive Measures and Recommendations 

• Avoid high-risk environments like live animal markets and maintain good hand hygiene. 
• Report sick animals and avoid consuming sick poultry. 
• Seek medical care promptly if exposed to infected birds or environments.