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Traveler Summary

Key Points

  • Dengue fever is a viral infection occurring in tropical and subtropical countries of the Americas, Asia, the Caribbean, the Indian Ocean islands, and the South Pacific and is acquired through the bite of day-biting mosquitoes.
  • Risk is increased for travelers going to populated urban areas of affected countries.
  • Symptoms include high fever, rash, severe headache and muscle, joint, and back pain.
  • Consequences of infection include bleeding, shock and death in a small percentage of patients and severe chronic fatigue lasting weeks to months in many others.
  • Prevention includes wearing long sleeves and long pants as well as observing daytime personal protective measures against mosquito bites.
  • No vaccine (for travelers) or preventive drugs are available.

Introduction

Dengue is a viral infection that occurs in certain countries of the Americas, Asia, the Caribbean, the Indian Ocean islands, and the South Pacific and is acquired through the bite of mosquitoes carrying the dengue virus. Dengue is the most common cause of fever in travelers returning from the Caribbean, Latin America, and Southeast Asia.

Risk Areas

Dengue infection is common in most tropical and subtropical countries of the Americas, Asia, the Caribbean, the Indian Ocean islands, and the South Pacific, primarily due to the broad geographic distribution of the infected mosquitoes. Recently, dengue infections have emerged in Angola, Kenya, Tanzania, and several countries in West Africa. The incidence of dengue is usually higher during warm and humid seasons in affected areas.

Transmission

Dengue virus is transmitted through the bite of infected mosquitoes. These mosquitoes may be found indoors in close contact with humans. These mosquitoes will interrupt their feeding at the slightest movement but return quickly to feed on the same or a different human host in the same location.

Unlike malaria-transmitting mosquitoes, dengue-transmitting mosquitoes are daytime feeders with 2 peak times of biting activity: 2 to 3 hours after dawn and mid-to-late afternoon. This pattern, however, changes to an all-day activity when the mosquitoes are indoors or during overcast days.

Risk Factors

Risk exists for persons in affected areas who have not been previously exposed to the dengue virus. The risk is higher for those staying in inappropriately screened facilities (e.g., places with nearby stagnant water such as discarded tires, flowerpots, and blocked rain gutters, which may host mosquito larvae). Risk is increased for travelers going to populated urban and residential areas in affected countries because the mosquito vectors can thrive in urban areas and indoors.

Symptoms

Symptoms most commonly appear 2 to 5 days following exposure (uncommonly, more than 7 days and, rarely, up to 14 days after exposure) and include sudden onset of high-grade fever, rashes, severe muscle, abdominal, joint, and lower back pain, severe pain behind the bony socket of the eye, nausea, vomiting, and generalized weakness. Fever that occurs more than 14 days after last exposure is not due to dengue. Mild bleeding from the nose, mouth, or under the skin (seen as bruising) may also occur.

Dengue has symptoms in common with chikungunya and Zika virus infections, which usually co-exist in the same areas because they are all transmitted by the same mosquitoes.

Consequences of Infection

Dengue infection can lead to severe fatigue (lasting for weeks or months) and, uncommonly, significant blood loss and organ (kidney, liver, brain) damage.

Need for Medical Assistance

Travelers who develop symptoms of dengue infection should seek immediate medical attention. Travelers with persistent fever should avoid using aspirin and other nonsteroidal anti-inflammatory drugs (because they prevent formation of blood clots) and should be seen by a health care professional when possible to ensure that another serious disease (e.g., malaria) is not present.

Prevention

Nonvaccine

Wear long sleeves and long pants and observe daytime personal protective measures against mosquito bites. See Insect Precautions. Additionally, containers with stagnant water that can serve as breeding sites for mosquitoes should be removed from the proximity of human habitation whenever possible.

No dengue vaccine is available for travelers; however, a dengue vaccine (Dengvaxia) is approved for persons aged 9 to 45 years residing in certain dengue-endemic countries who were previously infected with dengue virus.