Dengue Fever , What is it?

Dengue Fever
What is it?

Dengue fever is a type of arbovirus, which is short for arthropod-borne virus. The virus that causes dengue fever is carried by Aedes egypti mosquitoes, and is transmitted to humans through their bite. An organism that carries a disease, without actually developing the disease, is called a vector.



Who gets it?
The risk for being bitten by a mosquito that is carrying dengue fever is higher in Africa, Southeast Asia and China, the Indian subcontinent, the Middle East, South and Central America, the Caribbean Islands, Australia, and the South and Central Pacific. Dengue fever is considered "endemic" to certain regions, which means it is native to, or naturally occurring, in these areas. Dengue fever is more likely to occur during or shortly after the rainy season, when the mosquito population is larger. It also most commonly affects children under the age of 10. Dengue fever is rarely seen in the United States.

What causes it?
When a mosquito that is carrying dengue fever bites a person, the virus travels through the body's glands. Once in the glands, it multiplies and can enter the bloodstream. Dengue fever is not contagious, which means one person cannot pass it directly to another.

What are the symptoms?
It takes around five to eight days after being bitten by an infected mosquito for the virus to multiply. Then, symptoms including high fever, headache, chills, swollen lymph nodes, red eyes and eye pain, severe joint and muscle pain, flushed face, lower back pain, and general weakness appear suddenly. These symptoms last for two to three days. Afterward, the fever drops and the patient experiences heavy sweats, but feels better for around one day. This is followed by an increase in temperature, a rash, and a headache. The rash consists of small red bumps that begin on the arms and legs, but then spread to the back, abdomen, and chest. The soles of the feet and palms of the hands also turn red and swell. Symptoms usually last for up to 10 days, but the patient is weak and extremely tired for up to a month afterward. In more severe cases, patients have fever and headache, then develop a cough.

The dengue virus causes the blood vessels to swell and leak, creating small purple colored spots on the skin, called petechiae. The skin may appear bruised in areas where the bleeding is worse. Bleeding into the stomach causes severe abdominal pains and vomiting of a black, grainy substance that looks like coffee grounds. This severe bleeding, called hemorrhaging, occurs when the blood runs out of clotting factors. The damaged blood vessels eventually become so large that they are unable to supply the needed blood flow and the oxygen it carries to the body's tissues. This causes the body to go into shock, and can damage major organs such as the heart and kidneys.

Severe cases of dengue fever are called dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS). The body produces antibodies, which are disease-fighting cells, that protect the patient who has had dengue fever from being reinfected for around one year. However, more severe cases of dengue fever often occur in patients who have already had the virus, then are reinfected at a later time. Because the immune system recognizes the virus, it overreacts, causing more severe symptoms. Most people who have had dengue fever are more likely to have recurring similar viral infections over the years.

How is it diagnosed?
The arbovirus that causes dengue fever can be diagnosed by a blood test.

What is the treatment?
Dengue fever, like other arbovirus infections, must run its course. Treatment is focused on medications to lower fever and reduce pain, fluids to prevent dehydration, and bed rest. Blood transfusions are given in cases of severe blood loss, and oxygen must be given to patients with dengue shock syndrome (DSS). Almost all patients with dengue fever have a complete recovery. Those with DSS have a good prognosis if they receive immediate medical treatment.

Self-care tips
There are ways to protect yourself if you are traveling to a country that is known to have a high population of dengue fever-carrying mosquitoes. You can avoid mosquito bites by using a mosquito repellent spray or lotion on your body and clothes and staying in well-screened areas. Your sleeping area should have mosquito netting over the bed. Avoid leaving any containers of standing water outside where mosquitoes can breed. See a healthcare professional immediately if you have been in an area endemic to dengue fever and you have any illness with fever that lasts for more than two days.


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This information has been designed as a comprehensive and quick reference guide written by our health care reviewers. The health information written by our authors is intended to be a supplement to the care provided by your physician. It is not intended nor implied to be a substitute for professional medical advice.