Dengue is a mosquito-transmitted viral disease occurring chiefly
in tropical and subtropical areas of the world. Epidemic transmission
is usually seasonal, during and shortly after the rainy season.
There are no travel restrictions in any country with regard to
In Central and South America, dengue fever is reemerging as a
threat. In November 1995, the Pan American Health Organization
issued an alert that dengue and dengue hemorrhagic fever had reached
epidemic proportions in the Americas. At that time, more than
200,000 cases of dengue had been reported, as well as 5,500 cases
of the potentially fatal dengue hemorrhagic fever. Cases have
been reported among international travelers.
Generally, there is a low risk of acquiring dengue during travel
to tropical areas where dengue fever normally occurs except during
periods of epidemic transmission. Dengue outbreaks have occurred
with increasing frequency in recent years in most countries of
The risk is greatest in the Indian subcontinent, Southeast Asia,
Southern China, Central and South America (except Chile, Paraguay,
and Argentina), the Caribbean (except Cuba and the Cayman Islands),
Mexico, and Africa. There is a somewhat lower risk for travelers
to Taiwan and the Pacific Islands. The Middle East and Northern
Australia have a still lower risk of Dengue transmission. New
Zealand is free of dengue fever.
Since 1985, major epidemics have occurred in Mexico, Guatemala,
El Salvador, Nicaragua, Columbia, Bolivia, Brazil, and the Caribbean.
Dengue viruses are transmitted by Aedes mosquitoes, which are
most active during the day, with most biting activity occurring
in the morning and at twilight. Mosquitoes that transmit dengue
usually are found near human dwellings and often are present indoors.
Dengue is predominant in urban centers, but may be found in rural
areas. It is rarely found at elevations above 4000 feet. Dengue
fever may occur from 3 to 15 days after exposure to an infected
mosquito, commonly within 5 to 6 days.
Dengue fever is characterized by sudden onset, high fever, severe
headaches, intense joint and muscle pain, and fatigue. Nausea
and vomiting may occur. 3-4 days after the onset of fever, a skin
rash develops which may spread from the torso to the arms, legs,
and face. Infection is diagnosed by a blood test that detects
the presence of the virus or antibodies. The illness may last
up to 10 days, but complete recovery can take 2 to 4 weeks. Dengue
is commonly confused with other infectious illnesses such as influenza,
measles, malaria, typhoid, and scarlet fever.
More severe forms of the disease, "dengue hemorrhagic fever"
or "dengue shock syndrome" are very rare among travelers.
Symptoms initially may be indistinguishable from dengue fever,
but the hemorrhagic form of dengue fever is more severe and is
associated with loss of appetite, vomiting, high fever, headache
and abdominal pain, progressing to faintness, and generalized
bleeding. Shock and circulatory failure may occur. Untreated hemorrhagic
dengue results in death in up to 50 percent of cases.
If traveling in a malarious area, and develop a sudden high fever,
Assume that it could be malaria, even though it may be dengue
fever, or some other disease. Immediate blood tests should be
done for a definitive diagnosis.
See your physician if you become sick within a month of returning
from travel in a tropical area. Be prepared to give your complete
travel itinerary, so that the physician can evaluate the possibility
that your symptoms were caused by a dengue infection.
There is no vaccine for dengue fever; therefore the traveler should
avoid mosquito bites by using insect repellents on skin and clothing,
and remaining in well screened or air conditioned areas. For skin,
insect repellents should have a high (DEET) concentration. Spraying
clothing with permethrin (Permanone) will increase protection.
Travelers should use an insect spray containing pyrethrum indoors.
Even though the mosquitoes bite during the day, the use of bednets
is recommended when sleeping quarters are not screened or air
The symptoms of dengue can be treated with bed rest, ingestion
of large amounts of fluids, and medications to reduce fever, such
as acetaminophen. Aspirin should not be taken. Antibiotics are