Bird-flu viruses may be far more dangerous than previously thought. Researchers at University of Cambridge and University of Glasgow report that avian influenza viruses can replicate even at temperatures typical of a mammalian fever, effectively bypassing one of the body’s main antiviral defences.
According to the study, a viral gene known as PB1 is responsible for this resilience: viruses carrying the “avian-like” PB1 survive and multiply despite elevated temperatures, while human-origin flu strains are crippled by the same heat rise.
In laboratory tests using mice, a mere 2 °C rise, enough to simulate fever was enough to transform a lethal human-flu infection into a mild disease. But bird-flu viruses ignored that heat ramp and caused severe illness.
Researchers caution that the danger grows because bird and human flu viruses can swap genes , a mechanism believed to have fueled previous pandemics (1957, 1968). If a bird-flu strain with heat-resistant PB1 acquires human-flu infectivity, it could pose a grave pandemic threat.
The findings have big implications for global flu surveillance: scientists say it’s urgent to track not just bird-flu infections — but also their genetic ability to resist fever, as part of pandemic-readiness efforts.
