Indian Researchers Model Potential Spread of Bird Flu to Humans

Sat Dec 20 2025 14:00:27 GMT+0200 (Eastern European Standard Time)

Scientists from Ashoka University in India have developed a model predicting how bird flu (H5N1) could transition from birds to humans, warning of the critical early intervention needed to curb any potential outbreak.

A new study by Indian researchers shows that the spread of bird flu (H5N1) to humans could begin quietly with one infected individual, emphasizing the urgency for early containment measures. The study utilizes real-world data to simulate outbreak potential and highlights the risks associated with delayed interventions.

For years, scientists have warned that bird flu - better known as H5N1 - could one day make the dangerous leap from birds to humans and trigger a global health crisis.

Avian flu, a type of influenza, is entrenched across South and South-East Asia and has occasionally infected humans since emerging in China in the late 1990s. From 2003 to August 2025, the World Health Organization (WHO) has reported 990 human H5N1 cases across 25 countries, including 475 deaths - a staggering 48% fatality rate.

In the US alone, the virus has affected more than 180 million birds, spread to over 1,000 dairy herds in 18 states, and infected at least 70 people, primarily farmworkers, leading to several hospitalizations and one death. Additionally, in January, three tigers and a leopard died at a wildlife rescue center in India's Nagpur city from the virus that typically infects birds.

Symptoms in humans resemble a severe flu: high fever, cough, sore throat, muscle aches, and sometimes conjunctivitis, although some individuals are asymptomatic. While the risk to humans remains low, authorities closely monitor H5N1 for any mutations that could enhance its transmissibility.

This concern prompted new peer-reviewed modeling by researchers Philip Cherian and Gautam Menon at Ashoka University, simulating the potential spread of H5N1 in humans and identifying early intervention strategies to prevent it from spreading further.

The threat of an H5N1 pandemic in humans is genuine, but we can hope to forestall it through better surveillance and a more nimble public-health response, said Prof. Menon.

The study outlines that a pandemic would likely begin with a single infected bird passing the virus to a human, often a farmer or market worker. The real danger occurs if sustained human-to-human transmission follows.

Using BharatSim, a simulation platform initially designed for COVID-19 modeling, the researchers ran models based on a synthetic village in Tamil Nadu's Namakkal district, a crucial area in India's poultry production.

Findings indicate that early detection and isolation of primary contacts can contain outbreaks effectively if measures are implemented when two cases are identified. However, once the number of cases exceeds ten, traditional containment strategies may fail.

The study recommends timely interventions such as quarantining infected individuals and culling birds, stressing that these measures work best when deployed before the virus infects humans. The research points out the need for careful balance in quarantine timing, as premature quarantining can inadvertently increase virus transmission within households.

While the modeling provides critical insights into potential intervention strategies, researchers highlight caveats, including reliance on fixed community dynamics and not factoring in simultaneous outbreaks from migratory birds. Nonetheless, these simulations will aid public health officials in rapid response strategies should an outbreak occur.

Looking ahead, should H5N1 establish itself in the human population, the implications could mirror those of past pandemics, underscoring the importance of preparation and timely action in mitigating public health risks.