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West Nile Virus West Nile virus (WNV) was first detected in the United States in 1999 and has since rapidly spread across North America into all 48 continental states, seven Canadian provinces, and throughout Mexico. In addition, WNV activity has been detected in Puerto Rico, the Dominican Republic, Jamaica, Guadeloupe and El Salvador. WNV is transmitted by the bite of an infected mosquito, particularly Culex species. Symptoms from infection generally appear within 2-14 days after the bite of the mosquito. It is estimated that about 20% of people who become infected with WNV will develop “West Nile Fever.” Symptoms include fever, headache, tiredness, and body aches, occasionally with a skin rash (on the trunk of the body) and swollen lymph glands. While the illness can be as short as a few days, even healthy people have reported being sick for several weeks. The symptoms of severe disease include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis. It is estimated that approximately 1 in 150 persons infected with the West Nile virus will develop a more severe form of disease. Serious illness can occur in people of any age, however people over age 50 and some immunocompromised persons (for example, transplant patients) are at the highest risk for getting severely ill when infected with WNV. As of today, there are no vaccines that can prevent WNV transmission in humans. Eastern Equine Encephalitis Eastern Equine Encephalitis (EEE) is a mosquito-borne viral disease that occurs on the eastern half of the United States. EEE can affect humans, horses, and many species of birds. Although EEE is not as frequently transmitted in humans as WNV, it is regarded as the most serious mosquito borne disease in the U.S. because of the high mortality rate associated with this encephalitis. Birds serve as the primary host for EEE and are the primary reasons for potential amplifications of this virus. Many species of mosquitoes can become infected with EEE. The most important species associated with the bird-mosquito transmission cycle, however, is the Culiseta melanura. This species is not considered to be a significant vector of EEE to humans and horses because it primarily feeds on birds. Transmission to horses and humans requires mosquito species capable of creating a “bridge” between birds and uninfected mammals. Most of the bridge vectors consist of Aedes, Coquillettidia, and Culex species. Once bit by a potential “bridge” species, it generally takes from 3 to 10 days to develop symptoms of EEE. Many people don’t develop any apparent illness but for those who do, symptoms range from mild flu-like illness (inflammation of the brain), coma, and death. The mortality rate from EEE is approximately one-third, making it one of the most deadly mosquito-borne diseases in the United States. Approximately half of those persons who survive EEE will have mild to severe permanent neurologic damage. As of today, there are no vaccines that can prevent EEE transmission in humans. Other Mosquito Borne Diseases Yellow Fever is a disease that is primarily found in countries in Africa and South America. Yellow fever is a very rare cause of illness in travelers, but most countries have regulations and requirements that prevent travelers from going to these endemic countries without proper yellow fever vaccination. St. Louis Encephalitis is another major disease affecting the central nervous system in humans. Infected birds serve as hosts for this virus and the spread occurs through bites from Culex mosquitoes. Mild symptoms include headache and fever. More serious symptoms include stiff neck, disorientation, coma, paralysis, and death. There is no vaccine available for the virus and those most affected by the virus (i.e. the elderly) should avoid areas known to be problematic with St. Louis Encephalitis. La Crosse Encephalitis is a rare disease that also affects the central nervous system through a bite from an infected mosquito. The natural cycle of the infection typically involves the movement of the virus between the tree-hole mosquito, Ochlerotatus triseriatus, and woodland rodents. This virus is not typically found in eastern North Carolina. Most people infected with this virus will experience no symptoms. Those that do experience symptoms such as headache, nausea, and vomiting. Tremors, convulsions, and coma are seen in more severe cases. There is currently no vaccine for this virus. Malaria is the most commonly known mosquito borne disease. Each year, there are 350-500 million related cases worldwide, with over one million people dying from this disease. Malaria is caused by a parasite that is transmitted from Anopheles mosquitoes to humans. People with malaria often experience fever, chills, and flu-like illness. Left untreated, more sever complications and potential death can occur. Bednets, insecticides, and antimalarial drugs are effective tolls to fight malaria in areas where it is transmitted. |