About 200 types of mosquitoes are found in the United States. Most are simply a nuisance, with bites that cause itching and swelling, but 12 types spread germs that can sicken those who are bitten, according to the Centers for Disease Control and Prevention.

About 3,500 types of mosquitoes exist worldwide.

People experience varied symptoms after being bitten by a mosquito that spreads a virus, but they may include fever, rash, joint and muscle pain, headache, and nausea. West Nile and Zika are among the mosquito-spread viruses that have shown up in the United States but previously were found mainly in more tropical climates. Similarly, cases of dengue and chikungunya have occurred here as well, but most Americans who are sickened by those diseases contract them from travel in other parts of the world.

In addition, more than 2,000 cases of malaria, a life-threatening disease caused by parasites transmitted by mosquitoes, are reported in the United States each year, according to the CDC.

Most U.S. malaria cases are in people who traveled to other countries, the CDC says.

Stemming the spread of mosquito-borne disease starts with controlling the mosquito population, the Environmental Protection Agency says. To do this, the EPA suggests eliminating standing water (which is where mosquitoes lay their eggs), such as in rain gutters and uncovered buckets, and regularly changing the water in bird baths and wading pools.

If you are venturing into a marshy area or other mosquito habitat, wear long-sleeved shirts, pants and socks. Also, consider applying a mosquito repellent to exposed skin, preferably one containing DEET, according to the American Academy of Asthma, Allergy and Immunology. A repellent will not kill the mosquitoes but will make you less attractive to them. At home, change outdoor lights to yellow lights, which attract fewer mosquitoes.