Indian researchers warn that bird flu (H5N1) could jump from birds to humans and ignite a global crisis. Endemic in South and South-East Asia since the late 1990s, the virus has surged worldwide since 2020.
The World Health Organisation logs 990 human cases in 25 countries from 2003 to August 2025, with 475 deaths—a 48% fatality rate.
Updates note U.S. losses of 180 million birds, 1,000+ dairy herds in 18 states, and 70 human infections among farm workers, including hospitalisations and one death. Europe reports rising wild bird deaths.
In India, three tigers and a leopard succumbed to H5N1 at a Nagpur rescue centre in January 2025. Human symptoms include severe fever, coughs, aches, and conjunctivitis; some cases are asymptomatic. Officials watch for enhanced transmissibility.
Ashoka University’s Philip Cherian and Gautam Menon modelled scenarios in BMC Public Health, using real data and BharatSim simulations of a 9,667-person poultry-hub village in Tamil Nadu’s Namakkal.
“The threat of an H5N1 pandemic in humans is a genuine one, but we can hope to forestall it through better surveillance and a more nimble public-health response,” Prof. Menon told the BBC.
Transmission starts with a poultry worker, escalating via human spread. At two cases, quarantining primary contacts’ homes (family, carers) contains it. By 10 cases, it hits wider networks.
Bird culling succeeds pre-spillover. Prompt isolation halts secondary waves; vaccines aid thresholds. Early quarantine risks home transmission, late action fails.
Emory’s Seema Lakdawala cautions the model “assumes a very efficient transmission of influenza viruses”.
“Transmission is complex and not every strain will have the same efficiency as another,” she says. Only a “subset of flu-positive individuals actually shed infectious influenza virus into the air”—like Covid super-spreaders.
H5N1 in humans might mimic the 2009 swine flu, aided by antivirals and H5 vaccine stocks. Reassortment risks loom, but real-time models could guide swift containment.