While many mosquitoes are nothing more than annoying pests, with over 3,000 species worldwide, and 150 in the U.S., some are very dangerous. unfortunately, some mosquitoes are vectors for disease.

West Nile Virus (WN)

Originating in Africa the West Nile virus has spread across parts of Europe, the Middle East, Asia and here at home in the United States. In 2010, 981 infections were reported in the U.S. along with 48 deaths. For more information, statistics and symptoms on the West Nile Virus, go to:

CDC.Gov - West Nile

Mayo Clinic - West Virus

Eastern Equine Encephalitis (EEE)

The eastern equine encephalitis virus is not as common among humans as the WN virus. EEE is more commonly found in various bird species as well as horses. However, the fatality rate for persons infected with EEE is over 50 percent. Fortunately, there are typically fewer than 30 reported cases nationally in any given year. For more information, statistics, and symptoms on EEE go to:

CDC - Eastern Equine Encephalitis

Mayo Clinic - Easten Equine Encephalitis

LaCrosse Encephalitis (LAC)

Typically found in the Midwest states LaCrosse encephalitis has been on a slow but steady increase into the southeastern portion of the U.S. Unlike EEE, deaths are very rare, but the majority of infections are among children under the age of 15. The number of LAC cases a year is estimated to 80-100. For more information, statistics and symptoms on LAC go to:

CDC - LaCrosse Encephalitis (LAC)

Other Mosquito-borne illnesses include:

St. Louis Encephalitis
Dog Heartworm

Malaria

Anopheles Mosquitoes

Malaria is transmitted to humans by female mosquitoes of the genus Anopheles. Female mosquitoes take blood meals for egg production, and these blood meals are the link between the human and the mosquito hosts in the parasite life cycle. The successful development of the malaria parasite in the mosquito (from the “gametocyte” stage to the “sporozoite” stage) depends on several factors. The most important is ambient temperature and humidity (higher temperatures accelerate the parasite growth in the mosquito) and whether the Anopheles survives long enough to allow the parasite to complete its cycle in the mosquito host (“sporogonic” or “extrinsic” cycle, duration 9 to 18 days). In contrast to the human host, the mosquito host does not suffer noticeably from the presence of the parasites.

https://www.cdc.gov/malaria/about/biology/index.html

Lyme Disease 

Lyme disease is the most common vector-borne disease in the United States. Lyme disease is caused by the bacterium Borrelia burgdorferi and rarely, Borrelia mayonii. It is transmitted to humans through the bite of infected blacklegged ticks. Typical symptoms include fever, headache, fatigue, and a characteristic skin rash called erythema migrans. If left untreated, infection can spread to joints, the heart, and the nervous system. Lyme disease is diagnosed based on symptoms, physical findings (e.g., rash), and the possibility of exposure to infected ticks.  Laboratory testing is helpful if used correctly and performed with validated methods. Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics. Steps to prevent Lyme disease include using insect repellent, removing ticks promptly, applying pesticides, and reducing tick habitat. The ticks that transmit Lyme disease can occasionally transmit other tickborne diseases as well.

https://www.cdc.gov/ticks/