Zika virus
Introduction
The Zika virus is a member of the virus family Flaviviridae and the genus Flavivirus, transmitted by daytime-active Aedes mosquitoes, such as A. aegypti and A. albopictus. Its name comes from the Ziika Forest of Uganda, where the virus was first isolated in 1947. Zika virus shares a genus with the dengue, yellow fever, Japanese encephalitis, and West Nile viruses.
Epidemiology
Zika virus is primarily transmitted by the bite of an infected female mosquito. Other modes of transmission include sexual contact and blood transfusion, although these are less common. The virus has been isolated from a number of species in the Aedes genus, including A. aegypti, the yellow fever mosquito, which is considered the primary vector.
Clinical Manifestations
Most people infected with Zika virus are asymptomatic. Symptomatic infections are generally mild and characterized by a rash, fever, joint pain, and conjunctivitis. However, the virus can cause severe disease, including Guillain–Barré syndrome, and congenital abnormalities in babies born to women infected during pregnancy, the most notable of which is microcephaly, a condition characterized by an abnormally small head and often associated with developmental delays.
Diagnosis
Diagnosis of Zika virus infection is based on symptoms, travel history, and laboratory testing. Laboratory testing can be performed using reverse transcription polymerase chain reaction (RT-PCR) on serum or urine samples. Serologic testing can also be performed, although cross-reactivity with related flaviviruses can complicate interpretation of results.
Prevention and Control
There is no specific treatment for Zika virus infection. Management involves symptomatic treatment with rest, fluids, and analgesics. Prevention focuses on reducing mosquito populations and avoiding bites. This includes the use of insect repellent, wearing protective clothing, and staying in air-conditioned or screened-in areas.
Research and Vaccine Development
Research into Zika virus has increased significantly since the 2015 outbreak in Brazil. A number of vaccine candidates are currently in development, although none have been approved for use as of 2020. Research is also ongoing into potential antiviral treatments.