Arm yourself with mosquito-borne illness facts. In late summer and early fall, mosquitoes are a nuisance during your outdoor adventures. In fact, in the United States alone there are over 150 species of mosquitoes.

Because they are known for carrying diseases that can spread to humans, mosquitoes can be health concerns as well. It is important to stay informed and know how to reduce your risk.

What is West Nile virus?

In the continental United States, West Nile virus is the leading mosquito-borne illness. The virus has been spreading across the United States for 20 years, following the first reported cases in 1999.

Not all mosquitoes carry West Nile virus and it spreads when an infected mosquito bites a human or animal. In rare cases, it spreads through blood transfusions or from mother to baby during pregnancy. It’s not spread through coughing, sneezing or touching.

Emily Simpson, MD, infectious disease physician at Mercy Health, shares, “I think it’s important to know that symptomatic West Nile is really uncommon. Only 20% of people develop symptoms, and most people never develop any symptoms.”

A small number of people might develop fever, headache, muscle aches, nausea, or a rash. According to the CDC, less than one percent of those infected develop serious illness affecting the central nervous system.

Although uncommon, if you’ve been bitten by mosquitoes and think you might have West Nile virus, talk to a health care provider.

Are there other common mosquito-borne illnesses?

Around the world, mosquitoes carry and spread other diseases including various types of encephalitis (inflammation of the brain), Zika virus, and malaria. In the United States, most cases of mosquito-borne illnesses besides West Nile virus are types of encephalitis.

If you’re traveling abroad, it’s important to plan and know what risks there are related to insects in the countries you’ll be visiting.

How can you prevent bites?

Use insect repellent. Use EPA-registered repellents, such as DEET or Picaridin, to help protect against mosquitoes. Always follow the products label instructions. Consider natural ways to repel mosquitoes as well.

Wear long-sleeved shirts and long pants. Treating your clothing and gear with repellent can help. Be sure to follow the product instructions as some products shouldn’t be used directly on your skin.

Use screens on windows and doors. Prevent mosquitoes from getting into your home by using screens wherever possible.

Mosquito proof your outdoor spaces. You can spray insecticides around your home, following manufacturer instructions for safety. When choosing a product, consider what is safe near small children and pets if you have any. Look for any stagnant water to remove like buckets or birdbaths. If it’s a larger body of water, consider a larvicide solution which kills mosquito larvae but won’t harm other wildlife or pets.

Preventing infection by preventing mosquito bites is the best approach. However, if bitten, don’t scratch the bite and use over-the-counter antihistamines or calamine lotion to reduce the itch.

Some mosquito-borne diseases may be treated with medicines, but some have lasting consequences. If you get bit by a mosquito and experience fever, headache, muscle aches, nausea, swollen lymph nodes or a rash, contact a primary care provider.