What is Dengue Fever and How Do I Prevent Mosquito Bites?

Dengue Fever: Mosquito-transmitted Virus

Dengue Fever - Overview

Dengue fever is caused by viruses transmitted from person to person by mosquitoes. It is one of the most common insect-borne infectious diseases, occurring in tropical regions all over the world—including North, Central and South America, as well as Australia, Africa and Asia. An estimated 2.5 billion people live in regions at risk for infection. There are four different forms of dengue virus. Surviving infection from one does not prevent or reduce the risk of being infected by the others.

Insect Shield mosquito repellent clothes protect against infected mosquitoes that carry dengue fever. Our clothing and gear are worn by Insect Shield partners like Steve Baker when traveling or living in areas infested with mosquitoes, such as the jungles of South America. We recommend wearing long pants, a long sleeved shirt, socks and a hat treated with our permethrin repellent.

Symptoms of dengue infection include high fever, severe headache, joint and muscle pain, nausea and rash. If a rash develops, it appears 3 to 5 days after the fever, usually starting on the torso, then spreading to the arms, legs and face.
Infection with dengue fever does not always require hospitalization. But in many cases it is much more serious, resulting in severe—and sometimes fatal—hemorrhagic (external or internal bleeding) disease called dengue hemorrhagic fever (DHF).
Millions of cases of dengue fever occur each year, and up to hundreds of thousands of cases of DHF. Dengue epidemics have become more common in recent years. In some regions, dengue fever and DHF are a leading cause of hospitalization and death among children. According to the Centers for Disease Control and Prevention (CDC), dengue is the most significant mosquito-borne viral disease affecting humans.

Air travel increases the spread of dengue viruses between populated areas in the tropics. According to the CDC, cases of dengue are confirmed every year in travelers returning to the United States following visits to tropical and subtropical areas.

The CDC also says that the rise of dengue fever as a major public health problem has been most dramatic in the western hemisphere, and that there is a small but growing risk for dengue outbreaks in the continental United States.

For more details on dengue fever, see the Traveler’s Health section of the CDC website.

Dengue Fever - Frequently Asked Questions

What is dengue and how is it transmitted?
Dengue fever and DHF have become the most common arboviral (virus transmitted by insects) in the world. The virus is transmitted by day-biting Aedes aegypti mosquitoes that prefer to feed on people. There are four different strains of virus, and infection with one virus confers immunity against that strain, but not others—so multiple infections are possible in one’s lifetime. Infection with the dengue virus causes a range of symptoms from sub-clinical infection and nonspecific flu-like symptoms to severe and fatal DHF.
A first infection with dengue increases the risk of DHF in subsequent infections.
There are about 100 million cases of dengue around the world each year. But, since the majority of infections cause mild illness and are not reported, the actual number of cases may be five or ten times higher than this. Cases of DHF have increased greatly in Asia, the South Pacific, and tropical areas of the Americas over the past 25 years. The Aedes aegypti mosquito, which can carry dengue fever, is the most common species of mosquito in the United States.
Aedes aegypti mosquito, which transmits dengue fever

Aedes aegypti mosquito

Dengue fever has an incubation period of 3 to 14 days, after which the onset of symptoms occurs: high fever, severe frontal headache, as well as joint and muscle pain. Some patients experience a rash that spreads from the torso to the arms, legs and face. About 1% of cases turn into more serious DHF. Patients with DHF can develop hemorrhagic symptoms such as bruising, bleeding from the nose and mouth, circulatory failure, shock and death. The case fatality rate for DHF is about 5%.

Is there dengue in the United States?
Dengue is endemic in most countries of the South Pacific, Asia, the Caribbean, as well as tropical regions of the Americas and Africa. There have been occasional dengue cases in the United States associated with outbreaks in Mexico; a 2001 outbreak in Hawaii was likely imported by travelers from the South Pacific.
I’m traveling to an area where there is dengue. How can I protect myself?
Because there is no specific treatment available for dengue, you should take measures to prevent mosquito bites. Insect Shield® Repellent Apparel and Gear is proven and registered to repel mosquitoes, so it is a good option to help protect yourself from dengue. We’ve received positive feedback from travelers who wear our bug repellent products in tropical regions.
I’ve heard that global warming may lead to an increase in dengue worldwide. Is this true?
Various predictions have been made regarding changes in distribution of dengue with current models of climate change. There is a lot of agreement among experts that if warming trends continue, diseases like dengue will become more common in higher latitudes.
How is dengue treated?
Because it is a viral disease, antibiotics cannot be used to treat dengue infections. Acetaminophen can be used to treat pain and fever, but people with dengue should avoid aspirin or other anti-inflammatory medications. Intravenous fluids can be given if necessary.

Is there a vaccine available for dengue?
Dengvaxia is a dengue vaccine developed by Sanofi Pasteur. The CDC says this about Dengvaxia: It "is safe and effective in reducing dengue-related hospitalizations and severe dengue among persons who have had dengue infection in the past. Previous natural infection is important because Dengvaxia is associated with an increased risk for severe dengue in those who experience their first natural infection (i.e., primary infection) after vaccination."