Mosquitoes are one of many types of insect that carry infectious diseases.
Mosquitoes can carry more than 100 viruses that infect people and many more that infect animals. They also carry a wide variety of parasites that they pass can on through their bite to an animal or a human. In scientific terminology, when mosquitoes pass on infectious agents, they are called a "vector" for disease.
Mosquito-Borne Encephalitis
According to Margaret Hunt, professor of virology at the University of South Carolina School of Medicine, mosquitoes carry a large number of viruses that cause encephalitis, or swelling of the brain, in humans and animals. The St. Louis and West Nile encephalitis viruses, for example, infect both birds and people. Most infected people will not show any symptoms, but for those with compromised immune systems, infection can be serious or fatal. These viruses occur worldwide in regions inhabited by mosquitoes.
Dengue Fever
As of 2010, the mosquito-borne dengue fever virus was widespread in tropical and subtropical zones worldwide. According to Medicine Net, doctors identify dengue by a set of symptoms called the "dengue triad": fever, rash and headache. Dengue causes severe muscular and joint pain. In extreme cases, dengue can be a hemorrhagic fever, causing bodily tissues to break down. Symptoms of hemorrhage include blackened areas of skin--the result of subcutaneous bleeding--and bleeding from the gums or nose.
Malaria
A parasite called plasmodium, transmitted by anopheles mosquitoes, causes malaria. Sub-saharan Africa sees the largest number of deaths from malaria worldwide, according to the World Health Organization. People infected with malaria show symptoms of fever, chills, headache and vomiting about two weeks after an infected mosquito bites them. Some types of plasmodium linger in the liver, so people can appear to get better, only to suffer a relapse a few weeks or months later. Children are most vulnerable to serious illness or death from malaria.
Rift Valley Fever
Rift Valley fever is another viral disease carried by mosquitoes in sub-saharan Africa. It primarily occurs in sheep and cattle, but it can also infect people. Many infected people show no symptoms, while others experience mild flu-like effects. Those with weaker immune systems, like the elderly, can suffer jaundice and hemorrhagic fever. Damage to the retinas or encephalitis also develop in more serious cases.
Yellow Fever
Yellow fever is so called because one of its main symptoms is jaundice, the yellowing of the skin that results from impaired liver function. According to the University of Maryland Medical Center, most people suffer flu-like symptoms alongside jaundice for three or four days before recovering. In some people, however, infection recurs, and the internal organs break down. Yellow fever is carried by mosquitoes in South America and sub-saharan Africa. Older people are more at risk of serious infection.
Heartworm
Heartworm is a parasite that infects dogs. It originated in North America, but has spread to many locations worldwide. Mosquitoes ingest immature heartworms from infected dogs, then pass the worms on to healthy dogs. The heartworms grow on the right side of the dog's heart, where they take nutrients from the dog's bloodstream. Untreated, heartworm can be fatal. The Ontario Veterinary Medical Association advises that a preventative treatment is available from your veterinarian.
Tags: show symptoms, break down, carried mosquitoes, from malaria, hemorrhagic fever, immune systems