The risk for West Nile virus is now high in 10 Massachusetts communities, state public health officials said Tuesday.

Four mosquitoes from a testing tool of 371 tested positive for West Nile virus in Johnson County. No human cases have been diagnosed in the county, but one person each from Vanderburgh and Dekalb counties has tested positive, data from the Indiana Department of Health’s Mosquito Dashboard shows.

The Monroe County Health Department has confirmed that a batch of mosquitoes tested positive for West Nile Virus, and residents are urged to avoid areas where mosquitoes are found and take measures to prevent them from breeding around their homes.