Zika virus: Difference between revisions
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==Background== |
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= Zika = |
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*Single-stranded, positive-sense RNA virus in the [[Flaviviridae]] family, genus [[Flavivirus]] |
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== Definition == |
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*Discovered in 1947 in Zika Forest, Uganda |
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*Vector-borne infection carried primarily by [[Vector::Aedes aegypti]] mosquitoes, but possibly also [[Vector::Aedes albopictus]] mosquitoes |
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*Sexual transmission appears to be possible |
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*Now essentially endemic in tropics worldwide |
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==Clinical Manifestations== |
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* Infection with the Zika virus |
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*75% are asymptomatic |
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== Presentation == |
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*Incubation period of [[Usual incubation period::3 to 14 days]] |
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*[[Causes::Fever]], [[Causes::rash]], [[Causes::arthralgias]], [[Causes::conjunctivitis]], and [[Causes::headache]] |
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*May also see [[Causes::thrombocytopenia]], and can be severe enough to cause abnormal bleeding or hematomas |
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*Usually self-limited, lasting around 5 days |
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=== Postinfectious Complications === |
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* History |
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** Fevers |
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** Rash |
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** Arthralgias |
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* Signs & Symptoms |
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*Can have neurological disease in some cases, primarily presenting as [[Causes::Guillain-BarrΓ© syndrome]] |
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== Investigations == |
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*Rarely, [[acute myelitis]], [[meningoencephalitis]], [[acute disseminated encephalomyelitis]], [[reverse sensory polyneuropathy]] |
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=== Congenital Infection === |
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* Labs |
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** Serum rRT-PCR |
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*With maternal infection, causes a [[Congenital Zika|congenital syndrome]] of CNS abnormalities including [[microcephaly]], [[CNS calcifications in neonates|intracranial calcifications]], [[lissencephaly]], [[pachygyria]], and vision and hearing loss |
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==Differential Diagnosis== |
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*[[Dengue|Dengue virus]] |
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*[[Chikungunya virus]] |
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{| class="wikitable" |
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!Feature |
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![[Dengue]] |
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!Zika |
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![[Chikungunya]] |
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|- |
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|Asymptomatic |
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|40-80% |
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|35-85% |
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|3-28% |
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|- |
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|Fever |
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| +++ |
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| ++ |
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| +++ |
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|- |
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|Rash |
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| + |
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| +++ |
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| ++ |
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|- |
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|Conjunctivitis |
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|β |
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| ++ |
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| + |
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|- |
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|Arthralgia |
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| + |
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| ++ |
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| +++ |
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|- |
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|Myalgia |
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| ++ |
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| + |
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| + |
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|- |
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|Headache |
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| ++ |
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| + |
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| ++ |
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|- |
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|Hemorrhage |
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| ++ |
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|β |
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|β |
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|- |
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|Shock |
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| + |
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|β |
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|β |
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|- |
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|Thrombocytopenia |
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| +++ |
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| + |
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|β |
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|- |
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|Leukopenia |
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| ++ |
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|β |
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| ++ |
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|} |
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==Investigations== |
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*Serum rRT-PCR, ideally done within 10 days of symptoms onset |
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*Serology can be tested after 10 days of symptoms, but is non-specific |
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==Management== |
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*Supportive |
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*For risk of congenital disease |
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**If asymptomatic, no need to delay attempts at conception |
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**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 |
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**If symptomatic and diagnosis is not confirmed, then discuss with the patient |
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**If the woman is pregnant and man has compatible symptoms, should abstain from unprotected sex for the duration of pregnancy |
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[[Category:Flaviviridae]] |
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Latest revision as of 13:50, 20 September 2020
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-BarrΓ© 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 | β | ++ | + |
| Arthralgia | + | ++ | +++ |
| Myalgia | ++ | + | + |
| Headache | ++ | + | ++ |
| Hemorrhage | ++ | β | β |
| Shock | + | β | β |
| Thrombocytopenia | +++ | + | β |
| Leukopenia | ++ | β | ++ |
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
