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Most Common Illnesses You Get From Mosquito Bites

An annoying, itchy bump may not be the only thing a mosquito leaves behind after a bite. Mosquitoes can spread diseases, too. Viruses like West Nile and chikungunya may make you feel pretty bad for a time, but they aren't life-threatening. While malaria and yellow fever can be more serious, they aren't common in the U.S.

Fortunately, when you protect yourself from mosquito bites, you prevent the sickness as well as the scratching.

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Female mosquitoes need protein to lay their eggs. They get it by feeding on warm-blooded creatures, including birds, horses, and people. When a mosquito bites an infected animal (or a person, in some cases) and then bites you, it can pass the disease to your blood through its saliva.

Almost all mosquito-bite illnesses have similar symptoms:

  • Fever
  • Body aches
  • Rash
  • Headache

Sometimes they're mistaken for the flu. Most mild cases will go away with rest and time.

There are vaccines and medicines that can lessen your chance of getting some of these illnesses, even if you're bitten.

West Nile Virus

Most people who get West Nile virus don't have any symptoms. About 1 in 5 will have a fever and other flu-like symptoms. Feeling worn out could take months to go away completely. A few people get a more serious infection that causes brain swelling, or meningitis. There's a very small chance you could die.

People in 48 of the 50 U.S. states, Africa, Europe, the Middle East, and West and Central Asia have had West Nile.


Mosquitoes can pass on viruses that cause inflammation around your brain and spinal cord. (The brain swelling with a serious West Nile infection is a kind of encephalitis.) 

What type you could get depends on where you are:

  • LaCrosse -- the 13 states east of the Mississippi River
  • St. Louis -- throughout the U.S., especially Florida and Gulf of Mexico states
  • Eastern Equine -- Atlantic, Gulf Coast, and Great Lakes states; the Caribbean; Central and South America
  • Western Equine -- states west of the Mississippi River, areas of Canada and Mexico
  • Japanese -- Asia and the Western Pacific

Your doctor can give you medicine to ease your fever and sore throat. You'll need emergency care right away for severe symptoms, such as confusion, seizures, and muscle weakness, to prevent brain damage and other complications.

You can get shots to prevent Japanese encephalitis before you travel to the area.

Chikungunya Virus

Found mostly in the Caribbean and South America, chikungunya is now spreading in the U.S. It causes severe pain in your joints that may last several weeks. You'll need rest and fluids until symptoms go away. Your doctor may suggest pain relief medicine, too.

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