Zika virus
From IDWiki
Background
- Single-stranded, positive-sense RNA virus in the Flaviviridae family, genus Flavivirus
- Discovered in 1947 in Zika Forest, Uganda
- Vector-borne infection carried primarily by Aedes aegypti mosquitoes, but possibly also Aedes albopictus mosquitoes
- Sexual transmission appears to be possible
- Now essentially endemic in tropics worldwide
Clinical Manifestations
- 75% are asymptomatic
- Incubation period of 3 to 14 days
- Fever, rash, arthralgias, conjunctivitis, and headache
- May also see thrombocytopenia, and can be severe enough to cause abnormal bleeding or hematomas
- Usually self-limited, lasting around 5 days
Postinfectious Complications
- Can have neurological disease in some cases, primarily presenting as Guillain-Barré syndrome
- Rarely, acute myelitis, meningoencephalitis, acute disseminated encephalomyelitis, reverse sensory polyneuropathy
Congenital Infection
- With maternal infection, causes a congenital syndrome of CNS abnormalities including microcephaly, intracranial calcifications, lissencephaly, pachygyria, and vision and hearing loss
Differential Diagnosis
| Feature | Dengue | Zika | Chikungunya |
|---|---|---|---|
| Asymptomatic | 40-80% | 35-85% | 3-28% |
| Fever | +++ | ++ | +++ |
| Rash | + | +++ | ++ |
| Conjunctivitis | – | ++ | + |
| Arthralgia | + | ++ | +++ |
| Myalgia | ++ | + | + |
| Headache | ++ | + | ++ |
| Hemorrhage | ++ | – | – |
| Shock | + | – | – |
| Thrombocytopenia | +++ | + | – |
| Leukopenia | ++ | – | ++ |
Investigations
- Serum rRT-PCR, ideally done within 10 days of symptoms onset
- Serology can be tested after 10 days of symptoms, but is non-specific
Management
- Supportive
- For risk of congenital disease
- If asymptomatic, no need to delay attempts at conception
- If symptomatic and diagnosis is confirmed, counsel to delay attempts at conception for 2 months (women) or 3 months (men) after return from the endemic area
- If symptomatic and diagnosis is not confirmed, then discuss with the patient
- If the woman is pregnant and man has compatible symptoms, should abstain from unprotected sex for the duration of pregnancy
