There are currently no major outbreaks of Zika virus infection; however, local transmission still occurs in some countries, with small outbreaks occurring in others.
Majority of patients are asymptomatic; however, about 20% of infections result in a mild, self-limited illness with fever, rash, arthralgia, and conjunctivitis.
Infection may be more serious in pregnant women. There is strong scientific consensus that Zika virus is a cause of microcephaly and other congenital abnormalities. The range of abnormalities seen and the likely causal link to the virus suggest a new congenital syndrome.
Guillain-Barre syndrome and other neurological disorders are strongly associated with, and suspected to be caused by, Zika virus but the link is unproven and studies are ongoing, including to elucidate a possible mechanism.
Treatment of symptomatic infection is supportive and there are no specific antiviral therapies at this time. Prevention of mosquito bites through individual and public health measures is important to prevent infections.
A mild, usually self-limited infection when symptomatic (about 20% of infections) caused by the Zika virus (also known as ZIKV). The virus belongs to the Flaviviridae family (genus Flavivirus) and is an arbovirus (a virus transmitted by arthropods). It is named after the Zika forest in Uganda where it was first discovered in 1947.
It is transmitted to humans primarily by the Aedes species of mosquito which is also a vector for dengue, chikungunya, and West Nile viruses. Sexual transmission from person to person is also possible.
Congenital Zika syndrome is a recognised pattern of congenital anomalies in infants (i.e., microcephaly, intracranial calcifications or other brain anomalies, or eye anomalies, among others) associated with Zika virus infection during pregnancy. According to the World Health Organization, there is strong scientific consensus that Zika virus is a cause of microcephaly and these other congenital abnormalities. The Centers for Disease Control and Prevention has also concluded that there is a causal relationship between antenatal Zika virus infections and microcephaly/other brain abnormalities. Evidence to support a causal relationship has expanded in recent years; however, the total number of cases investigated in the published cohort or case-control studies remains small.
Guillain-Barre syndrome and other neurological disorders are strongly associated with and suspected to be caused by Zika virus infection but the link is unproven and studies are ongoing, including to elucidate a possible mechanism. Evidence to support a causal relationship has expanded in recent years; however, the body of evidence is still smaller than that for congenital abnormalities.
History and exam
Key diagnostic factors
- presence of risk factors
- maculopapular rash
- features of congenital Zika syndrome (infants)
- features of Guillain-Barre syndrome
Other diagnostic factors
- other constitutional symptoms
- gastrointestinal symptoms
- retro-orbital pain
- oedema of lower limbs
- transient hearing loss in adults
- residence in/travel from endemic area
- mosquito bites in endemic area
- unprotected sexual contact with infected individual
- blood transfusion from infected individual
- sperm donation from infected individual
- exposure to other infected body fluids
- exposure to infected human cells/tissues
1st investigations to order
- reverse transcriptase-polymerase chain reaction (RT-PCR)
- testing for other arboviruses
Investigations to consider
- antenatal ultrasound
- head circumference measurement (newborn)
- newborn further evaluation
- CT/MRI head (newborn)
- tests for Guillain-Barre syndrome
pregnant: with possible mosquito-borne or sexual exposure
congenital Zika syndrome
Zika-associated Guillain-Barre syndrome
- Dengue fever
- Chikungunya virus
- West Nile virus
- Laboratory testing for Zika virus and dengue virus infections
- Infant feeding in areas of Zika virus transmission, 2nd edition
Zika virusMore Patient leaflets
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