Water Restrictions Drop Mosquito-Borne Disease.

• Position: DROUGHT

Shallow pools of water on lawns are ideal breeding grounds for the mosquitoes that transmit West Nile virus. A study by scientists from the University of California at Los Angeles and Berkeley found that water-use restrictions during droughts led to a decrease in the number of mosquitoes that carry the virus.

"We are going to have a warmer climate, and the demand for water for outdoor irrigation in particular will go up," says senior author Dennis Lettenmaier, professor of geography at UCLA. "Efforts to reduce urban water use have a secondary benefit: they reduce the abundance of the mosquitoes that are responsible for West Nile virus."

"Mosquitoes are well adapted to finding small, isolated, or hard-to-find little pools of water that they can lay their eggs in," says Nicholas Skaff, an infectious disease scientist at UCal-Berkeley. There's a big connection between human water use, like irrigating your lawn or landscaping, and providing habitats for mosquitoes."

West Nile virus transmission is most common in the summer and early fall, which also is when outdoor water use peaks, as people try to keep their lawns...