The bird flu gene that laughs off a fever

Fever is one of the body's oldest defenses against flu. Heat stops the virus from copying itself in the airways. But one bird flu gene can shrug off this defense. Scientists at Cambridge and Glasgow found that a gene called PB1 helps the virus copy its genome even at high temperatures. Human flu strains replicate best in the cooler upper airways, around 33 degrees Celsius, and are knocked back as the body heats up. Bird flu with an avian PB1 gene thrives at 40 to 42 degrees. In mice, a two degree rise in body temperature turned deadly human flu into a mild illness. But bird flu stayed dangerous. The same gene swapped into human flu in the 1957 and 1968 pandemics. This gene swap still threatens us today. The study appeared in Science in late November 2025.

License: TypeCram Original