MOUNT HOLLY, N.J. — Officials plan to spray after confirming mosquitoes tested positive for the West Nile virus in four Burlington County towns.

Residents of Beverly, Evesham, Maple Shade and Washington Township are encouraged to stay indoors during Thursday night’s spraying.

County spokesman Ralph Shrom told The Courier-Post of Cherry Hill the positive results mostly came from traps near sewerage treatment plants.

West Nile virus is transmitted by mosquitoes that feed on birds that have the virus.

Most people exposed to it develop a mild virus. However, a 76-year-old Camden County man last summer was the first West Nile-related death in New Jersey since 2008.