Germs prefer an environment that’s cool, dry and UV-free
For flu germs, warm muggy weather is simply too close for comfort. It saps their vigor, cutting the period in which they remain infectious, according to a pair of new studies.
Although it remains a mystery why flu viruses are so sensitive to heat and humidity, both papers highlight conditions that can aid and abet infection — factors that might be thwarted by controlling aspects of the indoor environment.
One laboratory study measured how long highly pathogenic avian influenza remains infectious. Scientists applied known quantities of virus to a variety of surfaces that might be found outdoors on a chicken farm. Poultry have been implicated as a source of this particularly deadly type of bird flu.
The researchers kept samples either at room temperature or in a chilly environment more typical of a kitchen refrigerator. Relative humidity also varied from a low of between 15 and 46 percent to highs exceeding 90 percent. These conditions “are not un