Zika virus: Difference between revisions

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-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

@@ Line 1: / Line 1: @@
-== Background ==
+==Background==
-* Single-stranded, positive-sense RNA virus in the [[Flaviviridae]] family, genus [[Flavivirus]]
+*Single-stranded, positive-sense RNA virus in the [[Flaviviridae]] family, genus [[Flavivirus]]
-* Discovered in 1947 in Zika Forest, Uganda
+*Discovered in 1947 in Zika Forest, Uganda
-* Vector-borne infection carried primarily by [[Vector::Aedes aegypti]] mosquitoes, but possibly also [[Vector::Aedes albopictus]] mosquitoes
+*Vector-borne infection carried primarily by [[Vector::Aedes aegypti]] mosquitoes, but possibly also [[Vector::Aedes albopictus]] mosquitoes
-* Sexual transmission appears to be possible
+*Sexual transmission appears to be possible
-* Now essentially endemic in tropics worldwide
+*Now essentially endemic in tropics worldwide
 ==Clinical Manifestations==
@@ Line 12: / Line 12: @@
 *Incubation period of [[Usual incubation period::3 to 14 days]]
 *[[Causes::Fever]], [[Causes::rash]], [[Causes::arthralgias]], [[Causes::conjunctivitis]], and [[Causes::headache]]
+*May also see [[Causes::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 [[Causes::Guillain-Barré syndrome]]
+*Rarely, [[acute myelitis]], [[meningoencephalitis]], [[acute disseminated encephalomyelitis]], [[reverse sensory polyneuropathy]]
-*With maternal infection, causes a congenital syndrome of CNS abnormalities including [[Causes::microcephaly]], intracranial calcifications, lissencephaly, pachygyria, and vision and hearing loss
+=== Congenital Infection ===
+*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
-== Differential Diagnosis ==
+==Differential Diagnosis==
-* [[Dengue]]
+*[[Dengue|Dengue virus]]
+*[[Chikungunya virus]]
+{| class="wikitable"
+!Feature
+![[Dengue]]
+!Zika
+![[Chikungunya]]
+|-
+|Asymptomatic
+|40-80%
+|35-85%
+|3-28%
+|-
+|Fever
+| +++
+| ++
+| +++
+|-
+|Rash
+| +
+| +++
+| ++
+|-
+|Conjunctivitis
+|–
+| ++
+| +
+|-
+|Arthralgia
+| +
+| ++
+| +++
+|-
+|Myalgia
+| ++
+| +
+| +
+|-
+|Headache
+| ++
+| +
+| ++
+|-
+|Hemorrhage
+| ++
+|–
+|–
+|-
+|Shock
+| +
+|–
+|–
+|-
+|Thrombocytopenia
+| +++
+| +
+|–
+|-
+|Leukopenia
+| ++
+|–
+| ++
+|}
 ==Investigations==
@@ Line 25: / Line 95: @@
 *Serology can be tested after 10 days of symptoms, but is non-specific
-== Management ==
+==Management==
-* Supportive
+*Supportive
-* For risk of congenital disease
+*For risk of congenital disease
-** If asymptomatic, no need to delay attempts at conception
+**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 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 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
+**If the woman is pregnant and man has compatible symptoms, should abstain from unprotected sex for the duration of pregnancy
 [[Category:Flaviviridae]]