Zika virus infection

The Zika virus is a mosquito-borne flavivirus that is associated with fetal anomalies in humans, including microcephaly and brain abnormalities.

Zika virus infection is transmitted primarily via the bite of infected mosquitoes (Aedes aegypti and Aedes albopictus species), although vertical and sexual transmission has been reported. When the mosquito's saliva containing the Zika virus is inoculated into human skin, the virus can infect epidermal keratinocytes, skin fibroblasts in the subcutaneous layer, and the Langerhans cells. After replication in these local tissue cells and the regional lymph nodes, the Zika virus can disseminate via the lymphatics and bloodstream to reach other organs and tissues, including the CNS, skeletal muscles, myocardium.

In regions of the US with confirmed local transmission of Zika virus, the prevalence of birth defects potentially related to Zika virus infection is estimated at 3.0 per 1,000 live births.

In adults, acute infection typically results in a self-limiting febrile illness, but may also lead to the development to neurological complications (meningitis, meningoencephalitis, Guillain-Barre syndrome). In neonates, Zika virus can lead to birth defects (microcephaly) and death.

The case fatality rate in neonates is estimated at 8.3% (95% CI, 7.2-9.6).