Dengue fever is a viral illness caused by the bite of an infected mosquito. Although the illness was nearly eradicated from the Americas during the mid-20th century, dengue fever reemerged when disease-carrying mosquitoes returned to the region. Most cases of dengue fever among Americans occur in people infected while traveling to countries where the illness is prevalent. Early diagnosis, monitoring and treatment are important to prevent potentially life-threatening complications associated with dengue fever.
High-Risk Regions
The World Health Organization reports that the global incidence of dengue fever increased thirty-fold from 1955 to 2007. The illness most commonly occurs in tropical and subtropical regions inhabited by disease-carrying strains of the Aedes mosquito. Central and South American countries with high rates of dengue fever include Brazil, Colombia, Venezuela, Honduras, Mexico, Costa Rica, El Salvador and Guadeloupe. The illness is also prevalent in the Caribbean Islands. African nations with high rates of dengue infection include Sudan, Nigeria, Kenya, Tanzania, Angola, Madagascar, Mali and the Democratic Republic of Congo. Other areas with large numbers of dengue infections include Saudi Arabia, India and the countries of Southeast Asia.
Prevention
Protecting yourself from mosquito bites while visiting a high-risk region reduces your chance of contracting the dengue virus. Wear lightweight long-sleeved shirts and full-length pants outdoors, especially in the early morning and at dusk when mosquitoes are most active. Avoid areas with standing water, where mosquitoes typically breed. If you stay in a hotel or hostel, try to find one with intact window screens or air conditioning. With more rustic accommodations, use a mosquito net while sleeping. Insect repellent also reduces the likelihood of incurring mosquito bites.
Signs and Symptoms
A symptom-free incubation period of approximately three to seven days occurs after a bite from a dengue-carrying mosquito. A sudden high fever is generally the first sign of a dengue virus infection. The fever typically lasts two to seven days and may be accompanied by a headache, pain behind the eyes, muscle and joint pain and skin flushing. Loss of appetite, nausea and vomiting also prove common. When the fever breaks, you either enter the recovery phase of the illness or progress to a more serious form of the disease known as dengue hemorrhagic fever. This severe form of dengue is characterized by leakage of fluid into the lungs and other organs, falling blood pressure and spontaneous bleeding. Shock may develop with dengue hemorrhagic fever, endangering your kidneys, brain, heart and liver. Left untreated, dengue hemorrhagic fever can be fatal.
Warning Signs
The World Health Organization has identified a group of warning signs that indicate an increased risk of developing severe dengue. The warning signs include abdominal pain and tenderness, persistent vomiting, restlessness, drowsiness, tissue swelling, bleeding from the nose or gums, blood in the stool, shortness of breath, paleness and cold or clammy skin. Certain blood abnormalities detected with laboratory tests also indicate increased risk of severe dengue. If you develop any of the severe dengue warning signs during the course of your illness, seek immediate medical assistance. Call 911 or go to the nearest emergency room if you cannot reach your doctor right away.
Treatment
As of publication time, there is no antiviral medication available to kill the dengue virus. Treatment for the illness, therefore, focuses on controlling your symptoms and providing supportive care to optimize your chance for recovery. If you suspect that you may have dengue fever, see your doctor. She may recommend hospitalization or allow you to return home with frequent monitoring for the warning signs of severe dengue.
During the initial phase of the illness, your doctor is likely to recommend acetaminophen to reduce your fever and help relieve your headache and body aches. Do not take aspirin, ibuprofen, naproxen or other nonsteroidal anti-inflammatory drugs unless your doctor specifically instructs you to take the medication. These drugs may aggravate bleeding problems associated with severe dengue. Drink plenty of fluids to avoid dehydration. Call your doctor if you cannot keep fluids down because of nausea and vomiting. With early diagnosis and treatment, the overwhelming majority of people with even the most severe form of dengue fever recover from the infection.
References
- World Health Organization; Re-Emergence of Dengue and Emergence of Dengue Haemorrhagic Fever in the Americas; Francisco Pinheiro, M.D., Ph.D. et al; December 1997
- World Health Organization: Impact of Dengue
- Centers for Disease Control and Prevention; Dengue Epidemiology; October 2010
- Pan American Health Organization; Number of Reported Cases of Dengue in the Americas, 2010; May 2011
- Centers for Disease Control and Prevention: Dengue Map
- Centers for Disease Control and Prevention; Outbreak Notice Update: Dengue in Tropical and Subtropical Regions; May 2011
- "Dengue Guidelines for Diagnosis, Treatment, Prevention and Control"; World Health Organization; 2009
- Centers for Disease Control and Prevention; Symptoms and What to Do If You Think You Have Dengue; September 2009
- "Principles and Practice of Infectious Diseases, Sixth Edition"; Gerald L. Mandell, M.D. et al, editors; 2004
