‘ Climate change weakens immunity’

Tokyo, Feb. 5: Heat waves may reduce the body’s immune response to influenza, according to a study in mice which may have implications for how climate change may affect the future of vaccinations and nutrition.

Climate change is predicted to reduce crop yields and nutritional value, as well as widen the ranges of diseasespreading insects, said researchers from the University of Tokyo in Japan.

However, the effects of heat waves on immunity to influenza had not been studied before.

The study, published in the journal PNAS, investigated how high temperatures affect mice infected with influenza virus.

“Flu is a winter- season disease. I think this is why no one else has studied how high temperatures affect flu,” said Takeshi Ichinohe, an associate professor at the University of Tokyo.

The influenza virus survives better in dry, cold air, so it usually infects more people in winter.

However, Ichinohe is interested in how the body responds after infection.

The researchers housed healthy, young adult female mice at either refrigerator- cold temperature ( 4 degrees Celsius), room temperature ( 22 C), or heat wave temperature ( 36 C).

When infected with flu, the immune systems of mice in hot rooms did not respond effectively.

Most affected by the high heat condition was a critical step between the immune system recognising influenza virus and mounting a specific, adaptive response. Otherwise, heat- exposed mice had no other significant changes to their immune system.