Mosquitoes can spread diseases that make you sick. In Massachusetts, mosquitoes can give you eastern equine encephalitis (EEE) virus and West Nile virus (WNV).
Eastern equine encephalitis (EEE) is a rare but serious disease. Symptoms include high fever, stiff neck, headache, and lack of energy. Swelling of the brain, called encephalitis, is the most dangerous complication, and can cause coma and death. Most cases in Massachusetts occur in the southeastern part of the state.
West Nile virus infections are more common than EEE, but most do not cause any symptoms. Mild WNV infections can cause fever, headache and body aches, often with a skin rash and swollen lymph glands. A small number of people (less than 1 out of 100) who get infected with West Nile virus develop more serious illness; this is more common in people over the age of 50. Symptoms of serious illness include headache, high fever, stiff neck, confusion, muscle weakness, tremors (shaking), convulsions, coma, paralysis swelling of the brain, and sometimes death.
Only a small number of mosquitoes are infected at any given time, so being bitten by a mosquito does not mean you will get sick. However, the best way to avoid both of these illnesses is to prevent mosquito bites.