Nasty Infectious Diseases You Want To Avoid - Dengue Fever
This is an infectious viral disease with four distinct types, causing severe pain in the joints, fever, and rash. It is transmitted by mosquitoes. The disease is usually not serious, although there may be a prolonged convalescence. However, dengue may also cause a severe and fatal hemorrhagic disease called dengue hemorrhagic fever, in which patients' blood vessels leak, sending them into shock if they aren't promptly treated with fluids. Its name may be a Spanish adaptation of the Swahili Ki denga pepo that describes cramps that seize victims like a spirit. Others believe the term is derived from the Spanish word meaning "affectation," referring to the mincing walk adopted by untreated victims suffering from severe joint pain. For the same reason, the English called it "Dandy fever."
Dengue fever is a rapidly spreading disease now found in most tropical areas of the world. After decades of being only a minor nuisance in Latin America, as mosquito control programs shut down over the past 20 years it has become the most widespread disease of humans. There are now 2 billion people at risk and millions of new cases each year as epidemics caused by all four types of virus have become larger and progressively more frequent. Although the United States hasn't had any major epidemics of dengue since the 1940s, health authorities fear the disease may appear here at any time. A small number of people have developed dengue from local mosquitoes in Texas, and both species of mosquitoes that carry the dengue virus are firmly established in several southeastern states. While scientists can't predict the future incidence, it is anticipated that there will be increased dengue transmission in all tropical areas of the world during the next several years.
Dengue was called "break-bone fever" by 18th-century doctor Benjamin Rush during a Philadelphia epidemic in 1780, because of the severe bone pain; others called it "breakheart" fever because of the depression that often follows the illness. Through September 1996, 140,000 cases of classic dengue have been reported in Latin America; dozens have died from hemorrhagic dengue. During the mid-20th century, mosquito eradication efforts almost wiped out dengue in much of the Americas. Population growth and urban sprawl, together with lax official policies, led to the return of the mosquito.
Cause - Dengue fever is transmitted by urban Aedes mosquitoes (usually A. aegypti), which can be found across the United States and which prefers to feed on humans during the daytime. The mosquito may bite at any time during the day (especially indoors), in shady areas or when it is overcast. Frost wipes it out in northern areas, but the mosquito survives in many parts of the south, especially along the Gulf of Mexico.
Symptoms - Typically, the virus feels like a bad case of the flu, with sudden fever and severe frontal headaches and deep-muscle aches. There may be nausea and vomiting; the rash appears three to five days after onset of fever and may spread from torso to arms, legs, and face. The rash may be accompanied by itching and scaling. Most cases are mild, treated only with bed rest and fluids. Health officials are concerned about dengue because people who have suffered a bout with one of the viruses face a potentially life-threatening complication if they later catch any other dengue virus. The danger is dengue hemorrhagic fever, accompanied by a red rash, bruises, and bleeding from gums, nose, and gastrointestinal tract. This bleeding can trigger a loss of blood pressure that can lead to shock; as many as 1 out of 10 patients who develop the hemorrhagic fever will die.
Treatment - There is no specific treatment, although vaccines are currently being developed. Painkillers are given to relieve headache and other pain.
Prevention - People traveling to dengue and malaria-infested areas should use insect repellents containing DEET and stay in places with screened windows and mosquito nets for sleeping. Preventive drug therapy for malaria is also a good idea.