What is dengue hemorrhagic fever?
Dengue hemorrhagic fever (DHF) is a specific syndrome that tends to affect children under 10 years of age. This complication of dengue fever causes abdominal pain, hemorrhage (bleeding), and circulatory collapse (shock). DHF is also called Philippine, Thai, or Southeast Asian hemorrhagic fever or dengue shock syndrome.
DHF starts abruptly with continuous high fever and headache. There are respiratory and intestinal symptoms with sore throat, cough, nausea, vomiting, and abdominal pain. Shock occurs two to six days after the start of symptoms with sudden collapse, cool, clammy extremities (the trunk is often warm), weak pulse, and blueness around the mouth (circumoral cyanosis).
In DHF, there is bleeding with easy bruising, red or purple blood spots in the skin (petechiae), spitting up blood (hematemesis), blood in the stool (melena), bleeding gums, and nosebleeds (epistaxis). Pneumonia is common, and inflammation of the heart (myocarditis) may be present.
Patients with DHF must be monitored closely for the first few days since shock may occur or recur precipitously (dengue shock syndrome). Cyanotic (having a bluish coloration to the skin and mucus membranes) patients are given oxygen. Vascular collapse (shock) requires immediate fluid replacement. Blood transfusions may be needed to control bleeding.
The mortality (death) rate with DHF is significant. With proper treatment, the World Health Organization estimates a 2.5% mortality rate. However, without proper treatment, the mortality rate rises to 20%. Most deaths occur in children. Infants under 1 year of age are especially at risk of dying from DHF.
What are potential complications of dengue fever?
If dengue fever is severe, complications include leakage of fluid from the bloodstream causing fluid accumulation in the extremities, respiratory distress, severe bleeding, or organ impairment. Without proper treatment, these symptoms can be fatal.
Dengue hemorrhagic fever (DHF; see above) is a complication of dengue that usually affects children under 10 years of age when it occurs. This complication of dengue fever starts abruptly with continuous high fever and headache. DHF causes abdominal pain, sore throat, cough, nausea, vomiting, hemorrhage (bleeding), and circulatory collapse (shock). It can be fatal.
Another complication is postinfectious fatigue syndrome, which can occur in about one-quarter of hospitalized dengue patients.
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Is it possible to prevent dengue fever?
The transmission of the virus to mosquitoes must be interrupted to prevent the illness. To this end, patients are kept under mosquito netting until the second bout of fever is over and they are no longer able to transmit the virus to a biting mosquito.
The prevention of dengue fever requires control or eradication of the mosquitoes carrying the virus that causes dengue. In nations plagued by dengue fever, people are urged to empty stagnant water from old tires, trash cans, and flower pots. Governmental initiatives to decrease mosquitoes also help to keep the disease in check but have been poorly effective.
To prevent mosquito bites, wear long pants and long sleeves. For personal protection, use mosquito-repellant sprays that contain DEET when visiting places where dengue is endemic. There are no specific risk factors for contracting dengue fever except living in or traveling to an area where the mosquitoes and virus are endemic. Limiting exposure to mosquitoes by avoiding standing water and staying indoors for two hours after sunrise and before sunset will help, as the Aedes aegypti mosquito is a daytime biter with peak periods of biting around sunrise and sunset. It may bite at any time of the day and is often hidden inside homes or other dwellings, especially in urban areas.
Is there a dengue fever vaccine?
In April 2016, the WHO approved Sanofi Pasteur's Dengvaxia (CYD-TDV), a live recombinant tetravalent vaccine for dengue fever. Dengvaxia can be administered as a three-dose series in people 9-45 years of age who live in areas where dengue is endemic.
In clinical trials in Latin America and Asia involving more than 40,000 children and adolescents, Dengvaxia protected 66% of people aged 9 and older against dengue. Dengvaxia was very effective at protecting against severe dengue, which can be fatal, preventing 93% of severe cases, and reducing hospitalizations due to dengue by 80%.
Dengvaxia was initially approved in 2015 for use only in Mexico, the Philippines, Brazil, and El Salvador.
Several other vaccines for dengue are undergoing clinical trials, but none have yet been approved for use.
Where can people get more information on dengue fever?
"Dengue," Centers for Disease Control and Prevention
Reviewed on 8/2/2017
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2."Dengue" by CDC per University of South Carolina Biomedical Sciences