Health unit warns after West Nile virus detected in area mosquito traps Health officials say most infections are mild, but the virus can cause serious illness in rare cases. Article content A Southwestern Ontario public health unit is alerting residents after West Nile virus was detected in two mosquito traps in separate communities within its region. Try refreshing your browser, or Health unit warns after West Nile virus detected in area mosquito traps Back to video We apologize, but this video has failed to load. He said the Middlesex-London Health Unit is reminding people to “stay diligent” in protecting themselves because West Nile virus remains in the community. Read More West Nile's back: Avoid mosquito bites, health unit urges What are the risks of contracting West Nile virus in Canada?