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Frequently Asked Questions: Dengue Fever

What is dengue fever?  Dengue (pronounced den' gee) is a disease caused by any one of four closely related dengue viruses (DENV 1, DENV 2, DENV 3, or DENV 4). The viruses are transmitted to humans by the bite of an infected mosquito. It is estimated that there are over 100 million cases of dengue worldwide each year.

What is dengue hemorrhagic fever (DHF)? DHF is a more severe form of dengue infection. It can be fatal if unrecognized and not properly treated in a timely manner. DHF is caused by infection with the same viruses that cause dengue fever. With good medical management, mortality due to DHF can be less than 1%.

How are dengue and dengue hemorrhagic fever (DHF) spread? Dengue is transmitted to people by the bite of a mosquito that is infected with a dengue virus. The mosquito becomes infected with dengue virus when it bites a person who has dengue virus in their blood. The person can either have symptoms of dengue fever or DHF, or they may have no symptoms. After about one week, the mosquito can then transmit the virus while biting a healthy person. Dengue cannot be spread directly from person to person.

 What are the symptoms of the disease? The principal symptoms of dengue fever are high fever, severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding (e.g., nose or gums bleed, easy bruising). Generally, younger children and those with their first dengue infection have a milder illness than older children and adults.

 Dengue hemorrhagic fever is characterized by a fever that lasts from 2 to 7 days, with general signs and symptoms consistent with dengue fever. When the fever declines, symptoms including persistent vomiting, severe abdominal pain, and difficulty breathing, may develop. This marks the beginning of a 24- to 48-hour period when the smallest blood vessels become excessively permeable ("leaky"), allowing the fluid component to escape from the blood vessels into the lining of the abdominal and lung cavities causing fluid to fill the cavities. This may lead to failure of the circulatory system and shock, followed by death, if circulatory failure is not corrected. In addition, the patient with DHF has a low blood platelet count, a tendency to bruise easily, bleeding nose or gums, and possibly internal bleeding.

 What is the treatment for dengue? There is no specific medication for treatment of a dengue infection. Persons who think they have dengue should use analgesics (pain relievers) with acetaminophen and avoid those containing aspirin. They should also rest, drink plenty of fluids, and consult a health care provider. If they feel worse (e.g., develop vomiting and severe abdominal pain) in the first 24 hours after the fever declines, they should go immediately to the hospital for evaluation.

 Is there an effective treatment for dengue hemorrhagic fever (DHF)? As with dengue fever, there is no specific medication for DHF. It can however be effectively treated by fluid replacement therapy if an early clinical diagnosis is made. DHF management frequently requires hospitalization. 

Where can outbreaks of dengue occur? Outbreaks of dengue occur primarily in areas where mosquitoes that carry a dengue virus live. This includes most tropical urban areas of the world. Dengue viruses may be introduced into areas by travelers who become infected while visiting other areas of the tropics where dengue commonly exists. The risk of dengue infection for international travelers appears to be small. There is increased risk if an epidemic is in progress or visitors are in housing without air conditioning or screened windows and doors. 

 What can be done to reduce the risk of acquiring dengue? There is no vaccine for preventing dengue. The best defense against these viruses is prevention. The best preventive measure for residents living in areas infested with mosquitoes is to eliminate the places where the mosquito lays her eggs, primarily artificial containers that hold water.  To prevent mosquitoes from living and multiplying around your home or business:

 To prevent mosquitoes from living and multiplying around your home or business:

 DRAIN standing water:

• Drain water from garbage cans, buckets, pool covers, coolers, toys, flowerpots or any other containers where sprinkler or rainwater has collected.

• Discarded old tires, drums, bottles, cans, pots and pans, broken appliances and other items that aren't being used.

• Empty and clean birdbaths and pet's water bowls at least once or twice a week. 

• Protect boats and vehicles from rain with tarps that don't accumulate water.

• Maintain swimming pools in good condition and appropriately chlorinated. Empty plastic swimming pools when not in use.

COVER your skin with:

• CLOTHING - If you must be outside when mosquitoes are active, cover up. Wear shoes, socks, long pants and long sleeves.

• REPELLENT - Apply mosquito repellent to bare skin and clothing. Always use repellents according to the label. Repellents with 10-30% DEET, picaridin, oil of lemon eucalyptus, and IR3535 are effective. 

• Use mosquito netting to protect children younger than 2 months old. 

COVER doors and windows with screens:

• Keep mosquitoes out of your house. Repair broken screening on windows, doors, porches, and patios. 

How can we prevent epidemics of dengue fever? The emphasis for dengue prevention is on sustainable, community-based, integrated mosquito control, with limited reliance on insecticides. Preventing epidemic disease requires a coordinated community effort to increase awareness about dengue fever/DHF, how to recognize it, and how to control the mosquito that transmits it. Residents are responsible for keeping their yards and patios free of standing water where mosquitoes can be produced.

 For more information, visit:  

 Florida Department of Health http://www.doh.state.fl.us/Environment/medicine/arboviral/Dengue.html, or the 

 Centers for Disease Control and Prevention 

http://www.cdc.gov/dengue/