The state Department of Environmental Protection says a mosquito collected in York County has tested positive for West Nile virus, the county’s first positive sample for 2018.

The sample was collected May 16 in Manchester Township.

The DEP said people should be proactive by cleaning up their yards because mosquito surveillance in York County indicates the most common species in residential areas come from artificial containers such as buckets, tires, and tarps.

One bucket or tire in someone’s backyard can produce hundreds to thousands of mosquitoes in a year, the department said.