Dengue in travellers

Dengue is the most common arboviral infection in humans. It is transmitted by infected Aedes mosquitos. Dengue transmission occurs in over 100 countries, and around 400 million people are infected annually. It is spreading rapidly to new regions due to global warming and urbanization. There are four different dengue serotypes, and there is no lasting cross-serotype immunity after infection. Approximately 80% of infections are asymptomatic, but symptoms include fever, muscle pain, abdominal pain, nausea, vomiting, and bleeding. Severe complications include shock, respiratory distress, severe bleeding, and multi-organ failure due to plasma leakage and impaired coagulation. Severe complications typically occur between days 3 and 7 of the illness and are often preceded by warning signs; mortality is about 5% of those with severe dengue. Children and adults infected with dengue have some phenotypic differences in clinical manifestations and complications. Risk factors for severe illness include secondary infection with a different dengue serotype, younger age/elderly, obesity, diabetes, and other chronic comorbidities. Dengue can be diagnosed early using the NS1 antigen rapid test, or PCR tests; after day 5 of illness, these tests may be falsely negative and paired serology can be used to confirm diagnosis. There is no specific treatment for dengue, the main management is supportive care. Intravenous fluids should be administered judiciously during plasma leak and stopped promptly once no longer necessary. Recently, TAK-003 has become the first vaccine to be approved by the European Commission for individuals above 4 years of age, regardless of previous dengue exposure.