University of Virginia Historical Collections at the Claude Moore Health Sciences Library

Mosquito-Spread Diseases and a Mosquito Counteragent

Yellow Fever, Malaria, and West Nile Virus

“Adult Male of Stegomyia fasciata,” L.O. Howard, Mosquitoes: How They Live, How They Carry Disease, How They Are Classified, How They May Be Destroyed, (New York: McClure, Phillips & Co, 1901).

Yellow Fever

Yellow fever has had several different names throughout history: yellow jack, black vomit, and sometimes American Plague, because of its long history of devastating epidemics.

It is caused by an arbovirus of the family Flaviviridae, and spread to people by mosquitoes after they have first bitten infected humans or nonhuman primates.

In mild cases, only fever and headache occur. More severe infection causes chills, back pain, nausea, vomiting, and fatigue. After a short remission, about fifteen percent of cases develop into a very serious situation with jaundice, extreme prostration, internal hemorrhaging, and multiple organ failure. Up to half of these patients may die. Treatment for yellow fever is symptomatic, but a vaccine for the virus is available.

Malaria

“Female of Anopheles punctipennis,” L. O. Howard, Mosquitoes: How They Live, How They Carry Disease, How They Are Classified, How They May Be Destroyed, (New York: McClure, Phillips & Co, 1901).

Malaria

Malaria is caused by parasites of the genus Plasmodium that are transmitted to people by means of an infected Anopheles mosquito. The parasite is in the red blood cells of an infected person so transmission can also occur from blood transfusions, organ transplants, shared contaminated needles, and from mother to unborn child.

Symptoms may include fever, shivering, joint pain, vomiting, and tiredness. The classical attack is cyclical occurrence of coldness followed by fever and then sweating, occurring every several days. Untreated malaria may cause convulsions, renal failure, coma, and death. Cognitive impairments have been linked to malaria, especially in children, even after recovery. There are medications for prophylaxis and and multiple treatments for malaria.

West Nile

“Adult male of Culex pungens; with parts enlarged,” L. O. Howard, Mosquitoes: How They Live, How They Carry Disease, How They Are Classified, How They May Be Destroyed, (New York: McClure, Phillips & Co, 1901).

West Nile Virus

Like yellow fever, West Nile Virus is caused by an arbovirus of the family Flaviviridae, and spread to humans by mosquitoes. In the case of West Nile the common house mosquito Culex pipiens is the usual vector once it has bitten an infected bird. In the United State, the most common bird reservoir is the robin.

Most people who are infected with West Nile are symptom free. About 20 percent experience a mild febrile illness that is characterized by fever, headache, body aches, diarrhea, vomiting, joint pain, and rash. Sometimes fatigue and weakness linger for an extended period of time.

Less than one percent of the infected people develop a serious neurologic illness with symptoms that include neck stiffness, disorientation, decreased level of consciousness, seizures, coma, and paralysis. About ten percent of people with this level of infection die. Recovery for the others may take weeks or months with possible residual neurological impairment. There is currently no vaccine to prevent West Nile Virus for people. Treatment is supportive.

Toxorhynchites

Source: Historical Collections, Claude Moore Health Science Library, University of Virginia. Donated by Addeane S. Caelleigh, UVA School of Medicine.

The Anti-mosquito Mosquito

The Toxorhynchites are unusually large mosquitoes and are also called elephant mosquitoes. The adults are not blood-sucking so do not transmit disease to humans. The larvae actually eat other mosquito larvae, giving them the potential to lessen the population of those mosquitoes that do carry dangerous diseases.