A casualty was observed in Andhra Pradesh from bird flu virus marking India’s second recorded human fatality from H5N1 since 2021. 

What is Bird Flu? 

• About:  Bird flu, or avian influenza, is a highly contagious viral disease that affects both wild and domestic birds.  
  • It is caused by avian influenza A viruses, with subtypes such as H5N1 and H5N8 being particularly significant. 
• History of Human Cases: First human cases were reported in 1997 (Hong Kong). Most have occurred in Asia and were linked to close contact with infected birds. 
  • Between 2003 and February 2025, the World Health Organization (WHO) has recorded 972 cases of confirmed H5N1 influenza. 
• Transmission: H5N1 spreads primarily through direct contact with infected live or dead birds or contaminated environments (e.g., live bird markets). 
  • Rarely, transmission from infected mammals to humans has been observed. Though human infections are rare, H5N1 has a high fatality rate (~60%), much higher than the peak fatality of Covid-19 (~3%). Also, airborne transmission has not been confirmed in humans. 
  • Human-to-human transmission remains extremely rare. The virus continues to evolve, and if it mutates to allow sustained human-to-human transmission, it could trigger a global pandemic. 
    • Hence, H5N1 is listed as a priority disease under WHO R&D Blueprint. 
• Symptoms: Common symptoms include high fever, cough, sore throat, and muscle aches. 
  • Severe cases can lead to respiratory failure or neurological complications. Some individuals may remain asymptomatic despite exposure. 
• Treatment: Antiviral drugs like oseltamivir are effective, especially when administered early in high-risk or severe cases. 
• Vaccination: Current seasonal flu vaccines do not protect against H5N1.  
  • Some countries have developed H5N1-specific vaccines for emergency use.  
• Strains of Avian Influenza Viruses: 

  What are Influenza Virus Types?