Zika virus (ZIKV) is a single-stranded RNA virus of the Flaviviridae family, genus Flavivirus.


Transmission occurs through the bite of an infected Aedes mosquito. Perinatal transmission and possible person-to-person transmission have also been reported.


Serologic evidence and case reports of human ZIKV infection have been documented in Africa (including Central African Republic, Egypt, Gabon, Nigeria, Senegal, Sierra Leone, and Tanzania) and Asia (including India, Indonesia, Malaysia, the Philippines, Thailand, and Vietnam). In addition, larger sporadic outbreaks caused by ZIKV have been documented in the Pacific Islands in Yap State (Micronesia), French Polynesia, New Caledonia, the Cook Islands, and Easter Island. Cases have been detected in travelers returning from countries with suspected ZIKV activity.


Commonly reported signs and symptoms include fever, maculopapular rash, arthralgia, arthritis, myalgia, headache, retroorbital pain, and conjunctivitis. Other symptoms may include fatigue, edema, sore throat, cough, vomiting, and loose stools. Unlike in dengue infection, hemorrhagic manifestations have rarely been reported among people infected with ZIKV. The proportion of asymptomatic cases among people infected with ZIKV has not been established.


Because of the typical clinical features of fever, rash, and arthralgia, the differential diagnosis of ZIKV infection is broad. Preliminary diagnosis should be based on clinical findings and epidemiologic characteristics, including travel history and activities, although ZIKV infection may share these with other arboviral infections, including dengue and chikungunya.

Diagnostic testing can include nucleic acid testing (RT-PCR), virus isolation, or antibody detection; cross-reactivity with antibodies for other flaviviruses has been noted. Clinicians are encouraged to report suspected ZIKV infections to state or local health departments to determine if confirmatory testing is indicated and to reduce the risk of local transmission.


No specific antiviral treatment is available for ZIKV infection. Treatment of symptoms may include rest, fluids, antipyretics, and analgesics. As in other arboviral diseases, infected people should avoid mosquitoes while they are sick to reduce the risk of ongoing transmission.


Avoiding mosquito bites can protect against ZIKV infection (see Chapter 2, Protection against Mosquitoes, Ticks, & Other Arthropods). Avoiding exposure to bodily fluids (including unprotected sexual contact) of people with suspected ZIKV infection may also reduce transmission risk.


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Tai-Ho Chen, Ronnie Henry, and Marc Fischer