Dengue fever is caused by viruses transmitted from person to person by mosquitoes. Widespread, the disease occurs in tropical regions all over the world—including North, Central and South America, as well as Australia, Africa and Asia. The global distribution of dengue fever compares to that of malaria, with an estimated 2.5 billion people living in at-risk regions. The four types of dengue virus do not provide cross-protective immunity, so an individual can be at risk for as many as four dengue infections over time.
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 onset of fever, usually starting on the torso, then spreading to the arms, legs and face. In many cases, dengue fever does not require hospitalization. However, it can prove more serious, often resulting in a severe—and sometimes fatal—hemorrhagic disease called dengue hemorrhagic fever (DHF). It is estimated that millions of cases of dengue fever occur each year, and up to hundreds of thousands of cases of DHF.Dengue epidemics have become more widespread in recent years. In some regions, dengue fever and DHF have become 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 facilitates the spread of dengue viruses between population centers 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 has stated that the emergence of dengue fever as a major public health problem has proven most dramatic in the western hemisphere, and “there is a small, but significant, 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 at www.cdc.gov/travel/diseases/dengue.htm.
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. First infection with dengue increases the risk of DHF in subsequent infections. It is estimated that there are more than 100 million cases of dengue worldwide each year. However, since the majority of infections cause mild illness and are not reported, the actual number of cases in the population may be five or ten times higher than this. The incidence of DHD has increased dramatically in Asia, the South Pacific and tropical areas of the Americas over the past 25 years. Aedes aegypti, whichcan carry dengue fever is the most populous species of mosquito in the United States.
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. The illness is usually self-limiting, but approximately 1% of cases progress to the 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%.
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.
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 have worn our repellent apparel in tropical regions.
Various predictions have been made regarding changes in distribution of dengue with current models of climate change. There is consensus that if warming trends continue, diseases of the tropics such as dengue will become more prevalent in higher latitudes.
Because it is a viral disease, antibiotics cannot be used to treat dengue infections. Acetaminophen can be used to treat pain and fever, but aspirin or other anti-inflammatory medications should be avoided. Intravenous fluids can be given if necessary.
Is there a vaccine available for dengue?
There is no vaccine for dengue.