Dengue (pronounced DENG-gee or DENG-gey) fever is a mosquito-borne tropical disease caused by the dengue virus. Dengue fever is a severe, flu-like illness that affects infants, young children and adults, but seldom causes death. It tends to be more severe in people with compromised immune systems. Because it is caused by any one of five serotypes of dengue virus, it is possible to get dengue fever multiple times. However, an attack of dengue produces immunity for a lifetime to that particular viral serotype to which the patient was exposed.
Dengue goes by other names, including "breakbone fever" or "dandy fever." Victims of dengue often have contortions due to the intense pain in the joints, muscles, and bones, hence the name breakbone fever. Slaves in the West Indies who contracted dengue were said to have dandy fever because of their postures and gait.
Dengue fever is transmitted by the bite of a dengue infected female mosquito mainly of the species Aedes aegypti and to a lesser extent, Ae. albopictus. The mosquito becomes infected when it bites a person with dengue virus in their blood. The virus is not contagious and cannot be spread directly from person to person. It is mosquito-borne, so there must be a person-to-mosquito-to-another-person pathway. The full life cycle of the virus involves the mosquito as the vector (transmitter) and the human as the source of infection.
In a small proportion of cases, the disease develops into the life-threatening dengue hemorrhagic fever, resulting in bleeding, low levels of blood platelets and blood plasma leakage, or into dengue shock syndrome, where dangerously low blood pressure occurs.
Dengue hemorrhagic fever (also known as Severe Dengue), a more severe form of the viral illness was first recognized in the 1950s during dengue epidemics in the Philippines and Thailand. Today, severe dengue affects most Asian and Latin American countries and has become a leading cause of hospitalization and death among children and adults in these regions.
Symptoms of Dengue Fever
Symptoms, which usually begin four to six days after infection and last for up to 10 days, may include:
- Sudden high fever, as high as 106 F (41 C)
- Severe headaches
- Pain behind the eyes
- Severe joint and muscle pain
-Skin rash, which appears two to five days after the onset of fever
- Mild bleeding (such as nose bleed, bleeding gums, or easy bruising)
Sometimes, symptoms are mild and can be mistaken for those of the flu or another viral infection. Younger children and people who have never had the infection before tend to have milder cases than older children and adults.
If severe, dengue fever can damage the lungs, liver or heart. Blood pressure can drop to dangerous levels, causing shock and, in some cases, death.
Factors that put you at greater risk of developing dengue fever or a more severe form of the disease include:
Living or travelling in/to tropical areas. Being in tropical and subtropical areas increases your risk of exposure to the virus that causes dengue fever. Especially high-risk areas are Southeast Asia, the western Pacific islands, Latin America and the Caribbean.
Prior infection with a dengue fever virus. Previous infection with a dengue fever virus increases your risk of having severe symptoms if you're infected again.
Diagnosing Dengue Fever
Diagnosing dengue fever can be difficult, because its signs and symptoms can be easily confused with those of other diseases such as malaria, leptospirosis and typhoid fever.
Doctors can diagnose dengue infection with a blood test to check for the virus or antibodies to it. Your doctor will likely ask about your medical and travel history. Be sure to describe international trips in detail, including the countries you visited and the dates, as well as any contact you may have had with mosquitoes.
Treatment for Dengue Fever
There is no specific medicine to treat dengue infection. Any treatment given is concerned with relief of the symptoms and signs.
Your doctor may recommend that you drink plenty of fluids to avoid dehydration from vomiting and high fever. Acetaminophen (Tylenol, others) can alleviate pain and reduce fever. Avoid pain relievers that can increase bleeding complications such as aspirin, ibuprofen (Advil, Motrin IB, others) and naproxen sodium (Aleve, others). You should also have enough rest.
If you start to feel worse in the first 24 hours after your fever goes down, you should get to a hospital immediately to be checked for complications.
Preventing Dengue Fever
A way to prevent the disease is to prevent bites by infected mosquitoes, particularly if you are living in or travelling to a tropical area such as Central and South America, parts of Africa, parts of Asia, the Caribbean, and the Pacific.
This involves protecting yourself and making efforts to keep the mosquito population down.
What to do to stay protected:
Stay away from heavily populated residential areas, if possible.
Use mosquito repellents, even indoors.
When outdoors, wear long-sleeved shirts and long pants tucked into socks.
When indoors, use air conditioning if available.
Make sure window and door screens or nets are secure and free of holes. If sleeping areas are not screened or air conditioned, use mosquito nets.
If you have symptoms of dengue, speak to your doctor.
To reduce the mosquito population, get rid of places where mosquitoes can breed. These include old tires, cans, or flower pots that collect rain. Regularly change the water in outdoor bird baths and pets' water dishes.
If someone in your home gets dengue fever, be especially vigilant about efforts to protect yourself and other family members from mosquitoes. Mosquitoes that bite the infected family member could spread the infection to others in your home.
In late 2015 and early 2016, the first dengue vaccine, Dengvaxia (CYD-TDV) by Sanofi Pasteur, was registered in several countries for use in individuals 9-45 years of age living in endemic areas.
WHO recommends that countries should consider introduction of the dengue vaccine CYD-TDV only in geographic settings (national or sub-national) where epidemiological data indicate a high burden of disease.
Other tetravalent live-attenuated vaccines are under development in phase III clinical trials, and other vaccine candidates (based on subunit, DNA and purified inactivated virus platforms) are at earlier stages of clinical development. WHO provides technical advice and guidance to countries and private partners to support vaccine research and evaluation.