 The town tries to limit the mosquito population by treating public and private roadway catch basins and public school ground catch basins with larvicide. It's a program that began last month is renewed each four to six weeks. But the Greenwich Health Department says we can all do our part by eliminating standing water on our properties. We can also protect ourselves from getting West Nile by staying indoors during early morning and early evening hours when mosquitoes are most active. There were five human cases of West Nile in Connecticut last year, none fatal.