West Nile Virus is contracted when we are bitten by an infected mosquito. A mosquito becomes a carrier of the virus when it bites an infected animal, such as a bird, or often a house sparrow.
New research unexpectedly shows that house sparrows in “light-polluted” urban areas, such as the light used along streets and in parking lots, remain infectious for two days longer than house sparrows who spend their nights in natural dark conditions.
This longer period that house sparrows can pass on the virus to biting mosquitoes increases the potential for a West Nile Virus outbreak by about 41%, according to mathematical models. That is a huge increase that greatly increases the chance for West Nile Virus outbreaks.
It is still not understood why the virus remains active longer in house sparrows that live around artificial lights. A different study has shown that zebra finches that are stressed (a result of road noises, light pollution, etc.) are more likely to be bitten by mosquitoes. The researchers suggest new lighting technologies be developed that are detectable to humans and not wildlife.