Indian scientists have warned that bird flu (H5N1) may pose a real threat to global health if the virus gains the ability to sustainably transmit between humans, noting that the window for early intervention may be very narrow before any potential outbreak gets out of control.
According to a peer-reviewed scientific report published by BMC Public Health magazine, prepared by researchers at Ashoka University in India, Philippe Cherian and Gautam Menon, the transmission of the virus from birds to humans may begin with only one case, often with a person working in poultry farming or in markets or dealing directly with infected birds, but the real danger lies in the ensuing human-to-human transmission.
A glimmer of hope in control
The report indicates that bird flu has been endemic for years in South and Southeast Asia, and sporadic human infections have been recorded since the virus appeared in China in the late 1990s. According to the World Health Organization, 990 human infections with the H5N1 virus were recorded in 25 countries during the period from 2003 to August 2025, of whom 475 people died, i.e. a mortality rate of approximately 48%.
In the United States, the virus caused the death or culling of more than 180 million birds, and spread to more than a thousand herds of cows in 18 states. At least 70 people were infected, most of them farm workers, with several hospitalizations and one death recorded.
India also witnessed the death of a tiger and a leopard at a wildlife rescue center in the city of Nagpur early this year due to the virus.
In their study, the researchers relied on an open source simulation platform known as BharatSim, which had previously been used in modeling the Covid-19 pandemic, to simulate how the H5N1 virus would spread if it spread among humans in a realistic environment.
Infection leakage to humans
The study concluded that containing the outbreak becomes highly possible if very early intervention takes place, as models indicate that if only two cases are detected, and a strict quarantine is imposed on direct contacts and their families, the spread of the disease can be stopped. When the number of cases reaches about 10, the possibility of infection leaking into the wider community becomes very high, and controlling the outbreak becomes almost impossible.
To test the scenario in realistic conditions, the researchers chose a model village in the Namakkal district of Tamil Nadu, one of the most important poultry production areas in India, which includes more than 1,600 farms and about 70 million chickens.
The researchers stressed that the risk of the pandemic is currently still low, but the study highlights the importance of careful health monitoring and rapid and flexible response, as the decisive factor in preventing bird flu from turning into a global pandemic.
