Zika virus disease

Zika virus disease, also known as Zika fever, is an infectious arboviral disease caused by the Zika virus, a flavivirus closely related to dengue and yellow fever viruses. The disease is characterized by a generally mild febrile illness in most infected individuals, though it poses significant risks during pregnancy and has been associated with neurological complications. The etiologic agent is transmitted primarily through mosquito vectors, with Aedes aegypti identified as the main vector in tropical and subtropical regions.

Approximately 80% of Zika virus infections are asymptomatic. When symptoms occur, they are typically mild and self-limiting, lasting less than seven days. Clinical manifestations include fever, maculopapular rash, conjunctivitis, joint pain, and headache, which may resemble dengue fever. No deaths have been reported during the initial infection phase. However, maternal infection during pregnancy can result in congenital malformations including microcephaly and other brain abnormalities, with large-scale abnormalities observed in up to 42% of live births in affected pregnancies. Adult infections have been strongly associated with Guillain-Barré syndrome, a condition characterized by rapid onset muscle weakness and potential paralysis.

Zika virus transmission has been documented in 92 countries and territories worldwide, primarily in tropical and subtropical regions. Following the 2015-2016 epidemic in the Americas, which prompted a WHO public health emergency of international concern regarding microcephaly and neurological disorders, global case numbers declined from 2017 onwards. However, low-level transmission persists in several countries in the Americas and other endemic regions. The primary mosquito vectors include Aedes aegypti, Aedes hensilli, Aedes polynesiensis, and other Aedes species. While the definitive reservoir species remains unknown, serological evidence has been found in West African monkeys and rodents. Global surveillance capacity for Zika virus remains limited.

Zika virus is primarily transmitted through the bite of infected Aedes mosquitoes, with Aedes aegypti being the main vector in tropical regions. These mosquitoes are day-biting insects with peak activity in the early morning and late afternoon or evening hours. Alternative transmission routes include mother-to-fetus infection during pregnancy, sexual transmission from infected individuals (particularly from men to their partners), laboratory exposure, transfusion of blood and blood products, and potentially organ transplantation. The virus has been detected at concentrations up to 100,000 times higher in semen than in blood or urine, persisting for extended periods following infection.

Pregnant women represent the highest-risk group due to the severe consequences of congenital infection, including microcephaly and other brain malformations in the fetus. Individuals in tropical and subtropical regions where Aedes mosquitoes are prevalent face elevated exposure risk. Sexual partners of infected individuals, particularly pregnant women whose male partners may be infected, are at risk through sexual transmission. The association between Zika virus infection and Guillain-Barré syndrome indicates that adults with symptomatic infection may also face neurological complications, though the overall severity of adult disease remains generally mild.

Prevention strategies focus on reducing mosquito bites in areas where Zika virus transmission occurs and preventing sexual transmission through proper condom use. Personal protective measures include the use of insect repellent, wearing clothing that covers much of the body, sleeping under mosquito nets, and eliminating standing water where mosquitoes reproduce. No effective vaccine is currently available for Zika virus prevention or treatment, and vaccine development remains an active area of research. Pregnant women are advised to take particular precautions given the severe consequences of congenital infection.

Zika virus disease presents particular challenges for surveillance due to the high proportion of asymptomatic or mild infections that may go undetected. The incubation period is estimated at 3-14 days, and diagnosis requires specific laboratory testing of blood, urine, or saliva for viral RNA during acute illness, or serological testing for antibodies after symptoms have persisted for more than a week. Limited global surveillance capacity means that true disease burden in many endemic areas may be underestimated. The persistence of low-level transmission in multiple regions, combined with the risk of explosive outbreaks in naive populations, warrants continued vigilance in areas where competent mosquito vectors are present.

1. 1 WHO Health Topics. Zika virus disease.
2. 2 Wikidata. Zika fever.
3. 3 Wikipedia. Zika fever - Wikipedia.

ICD-10

A92.5

ICD-11

1D47

Total cases

33

Peak month

2016-03

Coverage

3 reporting countries · 2026-01-01 → 2026-05-09