Definition: Zika virus is a flavivirus primarily transmitted by *Aedes* species mosquitoes, known for causing Zika fever, which is often mild or asymptomatic, but can lead to severe congenital abnormalities, particularly microcephaly, and neurological complications like Guillain-Barré syndrome.
First identified in monkeys in Uganda in 1947, and later in humans in the 1950s, Zika virus remained relatively obscure until large-scale outbreaks occurred in the Pacific and then rapidly spread across the Americas starting in 2015. The primary mode of transmission is through the bite of infected *Aedes aegypti* and *Aedes albopictus* mosquitoes, which are also vectors for other diseases like dengue and chikungunya. Beyond mosquito bites, Zika can also be transmitted sexually, from mother to fetus during pregnancy (vertical transmission), and, less commonly, through blood transfusions. While many infections are asymptomatic, symptomatic cases typically present with a mild illness including fever, rash, joint pain, and conjunctivitis.
The profound public health significance of Zika virus lies in its association with severe birth defects, collectively known as Congenital Zika Syndrome (CZS), which includes microcephaly, ocular abnormalities, and and other developmental issues in infants whose mothers were infected during pregnancy. This discovery led to a public health emergency of international concern declared by the World Health Organization in 2016. Furthermore, Zika infection has been linked to an increased incidence of Guillain-Barré syndrome (GBS), a rare neurological disorder, in adults. Control efforts primarily focus on vector control strategies to reduce mosquito populations, personal protective measures against mosquito bites, and public health education regarding sexual transmission and travel precautions, as there is currently no specific antiviral treatment or widely available vaccine.
Key Context:
- Congenital Zika Syndrome (CZS): A spectrum of birth defects, most notably microcephaly, resulting from maternal Zika infection during pregnancy.
- Vector-borne Disease: Primarily transmitted by *Aedes* mosquitoes, highlighting the importance of integrated vector management.
- Guillain-Barré Syndrome (GBS): A post-infectious autoimmune disorder affecting the peripheral nervous system, recognized as a severe complication of Zika virus infection in adults.