Dengue Fever

Dengue fever is a disease caused by a family of viruses that are transmitted by mosquitoes.
Symptoms include severe joint and muscle pain, swollen lymph nodes, headache, fever, exhaustion, and rash. The presence of fever, rash, and headache (the "dengue triad") is characteristic of dengue fever.
Dengue is prevalent throughout the tropics and subtropics.
Because dengue fever is caused by a virus, there is no specific medicine or antibiotic to treat it. For typical dengue fever, the treatment is directed toward relief of the symptoms (symptomatic treatment).
The acute phase of the illness with fever and muscle pain lasts about one to two weeks.
Dengue hemorrhagic fever (DHF) is a specific syndrome that tends to affect children under 10 years of age. It causes abdominal pain, hemorrhage (bleeding), and circulatory collapse (shock).
The prevention of dengue fever requires control or eradication of the mosquitoes carrying the virus that causes dengue.
The first vaccine for dengue fever became available in December 2015 and is approved for use in dengue-endemic areas in Mexico, the Philippines, and Brazil


Dengue fever is a disease caused by a family of viruses that are transmitted by mosquitoes. It is an acute illness of sudden onset that usually follows a benign course with symptoms such as headache, fever, exhaustion, severe muscle and joint pain, swollen lymph nodes (lymphadenopathy), and rash. The presence of fever, itchy rash, and headache (the "dengue triad") is characteristic of dengue. Other signs of dengue fever include bleeding gums, severe pain behind the eyes, and red palms and soles.

Dengue (pronounced DENG-gay) can affect anyone but tends to be more severe in people with compromised immune systems. Because it is caused by one of five serotypes the 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 joint, muscle, and bone pain, 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 hemorrhagic fever is a more severe form of the viral illness. Symptoms include headache, fever, rash, and evidence of hemorrhage in the body. Petechiae (small red spots or purple splotches or blisters under the skin), bleeding in the nose or gums, black stools, or easy bruising are all possible signs of hemorrhage. This form of dengue fever can be life-threatening and can progress to the most severe form of the illness, dengue shock syndrome.

Dengue is prevalent throughout the tropics and subtropics. Outbreaks have occurred recently in the Caribbean, including Puerto Rico, the U.S. Virgin Islands, Cuba, and Central America. Cases have also been imported via tourists returning from areas with widespread dengue, including Tahiti, Singapore, the South Pacific, including the Philippines, Southeast Asia, the West Indies, India, and the Middle East (similar in distribution to the areas of the world that harbor malaria and yellow fever). Dengue is now the leading cause of acute febrile illness in U.S. travelers returning from the Caribbean, South America, and Asia.

New Delhi, India, is reporting an outbreak of dengue fever, with 1,872 testing positive for the illness as of September 2015.
In American Samoa, there have been 370 cases of dengue reported from May 2015 to September 2, 2015; 133 people have been hospitalized.
In 2015, two non-native species of mosquito were found in California, including the Aedes aegypti mosquito, which can transmit dengue. No cases of dengue have been reported yet.
Thailand reported the worst dengue outbreak in 20 years, with 126 deaths and 135,344 people infected with the virus, in October 2013.
In 2011, Bolivia, Brazil, Columbia, Costa Rica, El Salvador, Honduras, Mexico, Peru, Puerto Rico, and Venezuela reported a large number of dengue cases. Paraguay reported a dengue fever outbreak in 2011, the worst since 2007. Hospitals were overcrowded, and patients had elective surgeries canceled due to the outbreak

The U.S. Centers for Disease Control and Prevention (CDC) reports that from 1946 to 1980, no cases of dengue acquired in the continental United States were reported. Since 1980, a few locally acquired U.S. cases have been confirmed along the Texas-Mexico border, temporally associated with large outbreaks in neighboring Mexican cities.

A 2009 outbreak of dengue fever in the Florida town of Key West involved three patients who did not travel outside of the U.S. contracted the virus. Subsequent testing of the population of Key West has shown that up to 5% of the people living in the area have antibodies to dengue. In total, 28 people were diagnosed with dengue fever in this outbreak. In 2015, 210 people were diagnosed with dengue in Hawaii. This is the largest outbreak in Hawaii since 2001, when 122 people were diagnosed with dengue.

Dengue fever is common in at least 100 countries in Asia, the Pacific, the Americas, Africa, and the Caribbean. Thailand, Vietnam, Singapore, and Malaysia have all reported an increase in cases.

According to the CDC, there are an estimated 400 million cases of dengue fever with several hundred thousand cases of dengue hemorrhagic fever requiring hospitalization each year. Nearly 40% of the world's population lives in an area endemic with dengue. The World Health Organization (WHO) estimates 22,000 deaths occur yearly, mostly among children.


The virus is contracted from the bite of a striped Aedes aegypti mosquito that has previously bitten an infected person. The mosquito flourishes during rainy seasons but can breed in water-filled flower pots, plastic bags, and cans year-round. One mosquito bite can cause the disease.

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.

After being bitten by a mosquito carrying the virus, the incubation period ranges from three to 15 (usually five to eight) days before the signs and symptoms of dengue appear in stages. Dengue starts with chills, headache, pain upon moving the eyes, appetite loss, feeling unwell (malaise), and low backache. Painful aching in the legs and joints occurs during the first hours of illness. The temperature rises quickly as high as 104 F (40 C), with relatively low heart rate (bradycardia) and low blood pressure (hypotension). The eyes become reddened. A flushing or pale pink rash comes over the face and then disappears. The lymph nodes in the neck and groin are often swollen.

High fever and other signs of dengue last for two to four days, followed by a rapid drop in body temperature (defervescence) with profuse sweating. This precedes a period with normal temperature and a sense of well-being that lasts about a day. A second rapid rise in temperature follows. A characteristic itchy rash (small red spots, called petechiae) appears along with the fever and spreads from the extremities to cover the entire body except the face. The palms and soles may be bright red and swollen

The diagnosis of dengue fever is usually made when a patient exhibits the typical clinical symptoms of headache, high fever, eye pain, severe muscle aches, and petechial rash and has a history of being in an area where dengue fever is endemic. Dengue fever can be difficult to diagnose because its symptoms overlap with those of many other viral illnesses, such as West Nile virus and chikungunya fever.

In 2011, the U.S. Food and Drug Administration (FDA) approved a blood test called the DENV Detect IgM Capture ELISA to diagnose people with dengue fever. The FDA notes that the test may also give a positive result when a person has a closely related virus, such West Nile disease

Because dengue fever is caused by a virus, there is no specific medicine or antibiotic to treat it. For typical dengue, the treatment is concerned with relief of the symptoms and signs. Rest and fluid intake for hydration is important. Pain relievers such as aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) should only be taken under a doctor's supervision because of the possibility of worsening bleeding complications. Acetaminophen (Tylenol) and codeine may be given for severe headache and for joint and muscle pain (myalgia).

What is the prognosis for typical dengue fever?
Typical dengue is fatal in less than 1% of cases. The acute phase of the illness with fever and muscle pain (myalgia) lasts about one to two weeks. Convalescence is accompanied by a feeling of weakness (asthenia), and full recovery often takes several weeks

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 and 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.

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.

The first vaccine for dengue fever, Dengvaxia, became available in December 2015 and is approved for use in Mexico, the Philippines, and Brazil. It is only approved for use in people 9-45 years of age who live in dengue-endemic areas. In clinical trials, Dengvaxia reduced the chances of developing dengue by about 60%.

Five other vaccines for dengue are undergoing clinical trials, but none have yet been approved for use.