Delaware health officials say four people in the state have tested positive for West Nile virus.
The Division of Public Health announced Tuesday that three of the cases reported last month were in New Castle County and one was in Kent County. Officials say the people reported no symptoms, but the virus was found as part of bloodwork for a routine medical procedure.
While most people infected with the mosquito-borne virus won’t become ill, some — fewer than 20 percent — will develop symptoms such as a fever, headache, a rash or swollen lymph glands. The virus can also lead to potentially fatal encephalitis or meningitis.
There were no reported human cases in Delaware last year. But there were three cases in 2013 and nine in 2012 with one fatality.