GLEN BURNIE, Md. (WUSA) -   The Maryland Department of Agriculture moved to protect residents from West Nile Virus.

Crews decided to spray after a mosquito recently tested positive for the disease.

Matt Jablow reports that the state's Department of Agriculture sprays neighborhoods on a regular basis throughout the year, but Tuesday night's spraying was conducted after that recent positive test for West Nile.

So far this year, three deaths in the Washington area have been caused by West Nile, one each in Maryland, Virginia, and the District.

The Maryland Department of Agriculture says the spray it uses is extremely effective against mosquitoes, and says it does not harm people.