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More Dengue information from the Health Protection Surveillance Centre
Clinical
- Incubation period 3-14 days (usually 4-7)
- Abrupt onset fever, chills, headache, arthralgia
- Back pain ("breakbone fever") and prostration ( exhaustion)
- Rash in 50% - faint macular, erythematous with discrete pale spared areas
- Capillary test confirms capillary fragility
- Lasts up to 10 day
- May progress to haemorrhagic fever (beware petechial rash fragile gums) and shock (may be fatal)
- No vaccine available
- Prevention - avoid mosquito bites (advice)
- Severe 'flu like viral infection, all age groups
- Transmitted by Aedes mosquito bite
- Bites risk : daytime, tropics & subtropics
- Recently Comoro Islands.
Capillary test
Specificity >85%, sensitivity 30%
Apply BP cuff above venous pressure for 5 minutes. Positive = >2 petechiae distal to the cuff.
Labs
- Leucopenia with a relative lymphocytosis
- Thrombocytopenia
- Abnormal LFTs
- Clotting abnormalities if haemorrhagic / shock developing
- Confirm Dx with IgM antibodies against flavivirus
Management
- Supportive
Differential Dx
- Malaria - ALL need malaria screens
- Rickettsial infections
- Enteric fever
- Acute HIV seroconversion
Advice for travellers
Time: Precautions during daylight
Avoid risky areas: i.e. near water
Use mosquito repellents:
Dress safely: wear long sleeves, long trousers, socks and closed shoes.
Use air conditioning and screens
Links
- Health Protection Surveillance Site
- WHO information on Dengue Fever