Synopsis
Distinguish the major Aedes-borne viral syndromes, detect dengue capillary leak before shock, investigate infection by illness timing, and protect pregnancies and future pregnancies from Zika exposure.
- Dengue, chikungunya and Zika are transmitted by day-biting Aedes mosquitoes and overlap geographically and clinically.
- Dengue commonly causes abrupt high fever, severe headache, retro-orbital pain, myalgia, nausea and rash; warning signs cluster near defervescence when capillary permeability rises.
- Chikungunya is distinguished by abrupt fever with prominent, often symmetric and disabling polyarthralgia; joint symptoms can persist for months or years.
Key red flags
Deterioration as fever settles, usually during illness days three to seven, is characteristic of the dengue critical phase and must not be mistaken for recovery.
Severe abdominal pain, repeated vomiting, mucosal bleeding, lethargy, restlessness, liver enlargement or fluid accumulation emerging near defervescence predicts deterioration.
Investigation priorities
Identify malaria, physiological instability and common organ complications before arbovirus confirmation.
Management branches
A traveller returns from an Aedes-risk area with fever, rash, arthralgia or conjunctivitis.
- Record destinations, dates, outbreak exposure, mosquito bites, day of illness, pregnancy possibility, sexual partner travel and previous flavivirus infection or vaccination.
- Use ABCDE, obtain urgent malaria testing and baseline haematocrit, platelets, renal and liver profiles; screen separately for high-consequence infection when epidemiology requires it.
Key medicines
ParacetamolGive 500 mg to 1 g orally every four to six hours when needed, with at least four hours between doses and no more than 4 g in 24 hours for a suitable adult.
Isotonic crystalloid for dengue shockGive a protocolised intravenous crystalloid bolus or infusion matched to shock severity, then reassess perfusion, urine output, haematocrit and respiratory findings before any further fluid.