Information On Mosquito-Borne Diseases

Zika Virus

The Zika virus was first discovered in the Zika forest region of Uganda in 1947. The virus was of little concern until outbreaks occurred in South America, Central America, Mexico and the Caribbean in 2015 through the Aedes species of mosquito, which can live in parts of southern Minnesota according to the CDC. The Aedes mosquito is not established in central Minnesota yet.

While symptoms of Zika are typically mild, e.g. fever, rash, joint pain, conjunctivitis/pink eye. None of these symptoms last more than a week or so, though a very small number of those infected by Zika do die. The CDC confirmed Zika is a cause of microcephaly, a potentially catastrophic birth defect characterized by a small head and often a smaller-than-normal brain.

Individuals who travel to currently affected areas may become sick and should consider delaying travel, especially pregnant women.

West Nile Virus

West Nile virus first appeared in North America in 1999, and Minnesota in 2002. Infected mosquitoes can transmit the virus to humans and animals.

Most people infected with West Nile virus, 70-80%, will exhibit no symptoms at all. 20% of those infected with have a mild illness (some combination of: headache, fever, nausea, vomiting, joint pain, fatigue, etc.). A small percentage, less than 1%, will develop meningitis or encephalitis. Approximately 10% of those 1% of cases are fatal. Most serious cases occur in elderly patients.

La Crosse Encephalitis

The first La Crosse encephalitis case appeared in 1963 in Houston, Minnesota.

Most people infected with La Crosse encephalitis have no symptoms or a mild flu-like illness. A small percentage, especially children under 16 years old, may develop encephalitis. Approximately 1-3% of those cases are fatal, and an additional 15-30% of those patients have long-term nervous system problems. Most severe cases begin with a headache, fever, nausea and lethargy. The illness may progress into disorientation, seizures and coma.


Heartworm is commonly found in dogs and cats. It is a parasitic roundworm which can grow to about six-inches in length and can live in either the heart or arteries of the lungs.

Heartworm is very rarely found in people. An infection occurs after a mosquito bites an infected dog, and then bites a human. While heartworm is serious in dogs and cats, in humans it is not much of an issue and the heartworm usually dies on its own.

Heartworms can live in dogs, cats, ferrets and other smaller mammals for up to 7 years and can cause serious health issues with the potential for death if untreated. Common early signs include coughing, decreased appetite, weight loss and fatigue. Later symptoms can include dark or bloody urine, swollen belly, pale gums, labored breathing and finally heart failure.

How To Avoid Mosquito Bites

With these potential health threats from mosquitoes, it’s important to protect yourself, your family, friends and pets. You can do this by reducing the chance of being bitten.

  • Use insect repellents when you go outdoors. Always follow the instructions on the label.
  • Wear long sleeves/pants and socks when outdoors. You can even spray the outside of your clothing with insect repellent for extra protection. Don’t spray repellent under your clothing.
  • Throw away or store any items which can accumulate standing water. If these items are used frequently, flip them upside-down so water does not collect.
  • Adjust sprinklers to prevent over-watering.
  • Inspect your roof, outdoor faucets and air conditioning units for leaks. Repair to prevent standing water.
  • Treat standing water with a larvicide to control mosquito larvae. Stock ornamental ponds with mosquito eating fish such as western mosquito fish, goldfish and guppies.
  • Clean gutters frequently. Debris can clog gutters, causing water to pool.
  • Install or repair screens on windows and doors to keep mosquitoes out of your home. Use air conditioning if you have it.
  • Most importantly, call Valley Green Companies. With licensed mosquito control professionals, all it takes is one call to stop the mosquitoes in your lawn dead in their tracks for up to three weeks per treatment.

Why Choose Valley Green Companies For Mosquito Control?

Valley Green Companies has highly-trained, professional technicians who can provide a relaxing, pest-free lawn for your and your family. Click here to learn more about our mosquito control program, or contact us if you have additional questions about mosquito-borne diseases which weren’t answered here. Thank you for choosing Valley Green Companies!