Dengue fever is a disease spread by the Aedes aegypti mosquito and is caused by one of four dengue viruses. Once you are infected with one of the dengue viruses, you will develop immunity to that virus for the rest of your life. However, you can still be infected with the other three viruses. It is possible to get all four dengue viruses in your lifetime. The viruses that cause dengue fever are related to those that cause yellow fever and West Nile virus infection.
The estimates that at least 400 million cases of dengue fever occur across the globe every year. Tropical regions are heavily affected. Areas that have the greatest risk of infection include:
- Sub-Saharan Africa
- Central America
- the Caribbean
- Pacific Islands
- South America (except Argentina, Chile, and Paraguay)
- Southeast Asia (especially Thailand, Singapore)
- Southern China
- northern parts of Australia
Very few cases occur in the United States. Most diagnosed cases occur in individuals who contracted the disease while traveling abroad. However, risk of infection is increasing for residents of Texas who live in areas that share a border with Mexico. Additionally, cases have been on the rise in the Southern United States. As recently as 2009, an outbreak of dengue fever was identified in Key West, Florida.
Dengue fever is transmitted via the bite of a mosquito harboring the dengue virus. Person-to-person transmission does not occur.
If you contract dengue fever, symptoms usually begin about four to seven days after the initial infection. In many cases, symptoms will be mild. They may be mistaken for symptoms of the flu or another infection. Young children and people who have never experienced infection may have a milder illness than older children and adults. Symptoms generally last for about 10 days and can include:
- sudden, high fever (up to 106 degrees Fahrenheit)
- severe headache
- swollen lymph glands
- severe joint and muscle pains
- skin rash (appearing between two and five days after the initial fever)
- mild to severe nausea
- mild to severe vomiting
- mild bleeding from the nose or gums
- mild bruising on the skin
- febrile convulsions
Doctors use blood tests to check for viral antibodies or the presence of infection. If you experience dengue symptoms after traveling outside the country, you should see a healthcare provider to check if you are infected.
There is no medication or treatment specifically for dengue infection. If you believe you may be infected with dengue, you should use over-the-counter pain relievers to reduce your fever, headache, and joint pain. However, aspirin and ibuprofen can cause more bleeding and should be avoided.
Your doctor should perform a medical exam, and you should rest and drink plenty of fluids. If you feel worse after the first 24 hours of illness—once your fever has gone down—you should be taken to the hospital as soon as possible to check for complications.
A small percentage of individuals who have dengue fever can develop a more serious form of disease known as dengue hemorrhagic fever.
Dengue Hemorrhagic Fever
The risk factors for developing dengue hemorrhagic fever include:
- having antibodies to dengue virus from a previous infection
- being under the age of 12
- being female
- weakened immune system
This rare form of the disease is characterized by:
- high fever
- damage to the lymphatic system
- damage to blood vessels
- bleeding from the nose
- bleeding from the gums
- liver enlargement
- circulatory system failure
The symptoms of dengue hemorrhagic fever can trigger dengue shock syndrome. Dengue shock syndrome is severe, and can lead to excessive bleeding and even death.
There is no vaccine to prevent dengue fever. The best method of protection is to avoid mosquito bites and to reduce the mosquito population. When in a high-risk area, you should:
- avoid heavily populated residential areas
- use mosquito repellent indoors and outdoors
- wear long-sleeved shirts and pants tucked into socks
- use air conditioning instead of opening windows
- ensure that window and door screens are secure, and any holes are repaired
- use mosquito nets if sleeping areas are not screened
Reducing the mosquito population involves getting rid of mosquito breeding areas. These areas include any place that still water can collect, such as:
- pet dishes
- empty planters
- flower pots
- any empty vessel
These areas should be checked, emptied, or changed regularly.