Those zip codes include 40212, 40213 and 40214, according to the Louisville Metro Department of Public Health and Wellness.
"It's peak season for mosquito activity, and it's important that we all be vigilant and take precautions when enjoying the outdoors this time of year", said CU Boulder Assistant Director for Environmental Operations Rob Lenahan.
West Nile, which is spread by the infected mosquitoes, doesn't cause symptoms in most people, but those who do become sick may contract a fever or experience a more severe infection in their brain or spinal cord.
Maryland's Department of Agriculture said it found the virus in mosquitoes collected in the Riverdale Park area of Prince George's County.
China warns of new tariffs on USA goods
Secretary of State Mike Pompeo at a meeting of the Association of Southeast Asian Nations (ASEAN) in Singapore on Friday. US President Donald Trump has said he is determined to reduce the large US trade deficit with China.
Less than 1 percent of infected people develop the sometimes fatal neuro-invasive illness.
Those most at risk for serious complications are people older than 50 and people with suppressed immune systems. For example, oil of lemon eucalyptus should not be used on children under 3 years of age and DEET should not be used on children less than 2 months of age. "By eliminating places for mosquitoes to lay eggs, using insect repellent and other protective measures, and targeted use of pesticides, we can all make sure Pennsylvanians are protected". Spraying clothes with repellent will give extra protection - seeing as some mosquitoes bite through clothes. Manitobans are urged to protect themselves by staying indoors during dusk and dawn, using mosquito repellent, and wearing white, long-sleeved shirts and trousers instead of shorts. Wearing long-sleeve clothing and socks also helps prevent bites.