Diseases that can be Transmitted by Mosquitoes

While mosquito-transmitted disease is not as common in Minnesota as it is in tropical climates, there are several diseases of potential concern to Minnesota residents. Minnesota residents who travel to other countries can return with tropical diseases such as malaria or dengue.

  • West Nile Virus (WNV)
    West Nile virus is a disease transmitted to people, horses, and birds. It is the most commonly reported mosquito-transmitted disease in Minnesota. Most people infected with West Nile virus show no symptoms or flu-like symptoms, but some (primarily elderly) have more severe illness. West Nile virus was found in Minnesota in 2002 will remain a public health concern in the foreseeable future.

  • La Crosse Encephalitis (LAC)
    La Crosse encephalitis is a viral disease that is transmitted by the Tree Hole mosquito. It has been responsible for up to 13 cases of severe illness (primarily in children) each year in Minnesota.

  • Jamestown Canyon Virus (JCV)
    Jamestown Canyon virus, which is transmitted by several different species of mosquitoes,  is a rarely reported cause of illness in humans with only two cases being reported in Minnesota since 2002 (single cases in 2002 and 2013).

  • Western Equine Encephalitis (WEE)
    Western Equine Encephalitis is a disease transmitted to people, horses, and birds. It is caused by a virus that is transmitted by the same mosquito species that commonly transmits WNV in western Minnesota. During 1941, there was a large regional outbreak of Western equine encephalitis. There may have been as many as 791 cases in Minnesota that year with 90 deaths. In more recent years, Minnesota has had infrequent and smaller outbreaks of WEE (15 human cases in 1975, single cases in 1983 and 1999).

  • Eastern Equine Encephalitis (EEE)
    Eastern equine encephalitis is a rare illness in humans, and only a few cases are reported in the United States each year. Many people infected with EEE virus show no symptoms but some (primarily children) have severe illness.

  • St. Louis Encephalitis (SLE)
    CDC; Cases of St. Louis encephalitis are usually the result of unpredictable and intermittent localized epidemics. SLE has not been reported in Minnesota since the 1970’s. Attention: Non-MDH link

  • Malaria
    CDC; Malaria is still a public health concern in North America  even though local exposure to the disease hasn’t occurred in nearly 100 years. People who travel to or have lived in other areas of the world may be at risk and should be familiar with the symptoms of the disease and the medications used to prevent infection. Attention: Non-MDH link

  • Dengue
    CDC; Dengue fever is primarily a tropical disease and rarely occurs within the continental United States.  In recent years, Dengue has occurred in southern states, including Texas and Florida. People who travel to or have lived in other areas of the world may be at risk and should be familiar with the symptoms of disease as well as preventive measures used to avoid mosquito bites.  Attention: Non-MDH link

  • Chikungunya
    CDC; Chikungunya fever is a viral illness not currently found in the United States.  The virus is primarily found in Africa and Asia yet was found in 2013 for the first time on the Caribbean islands.  People who travel to or have lived in at-risk areas may be at risk and should be familiar with the symptoms of disease as well as preventive measures used to avoid mosquito bites.  Attention: Non-MDH link

Updated Wednesday, May 21, 2014 at 11:19AM