Zika virus is a flavivirus transmitted by Aedes mosquitoes. Clinical manifestations of Zika virus infection occur in approximately 20 percent of patients and include acute onset of low-grade fever with maculopapular rash, small joint arthralgia , nonpurulent conjunctivitis.The greatest threat is that Zika virus infection has also been associated with congenital microcephaly and fetal demise.

Initially  Zika virus infection  occurred in Africa, Southeast Asia, and the Pacific Islands; but now since 2014 there are now cases in  the Americas and Europe.  As of February 2016,  according to the CDC countries at risk now include Barbados, Bolivia, Brazil, Cape Verde, Colombia, Costa Rica, Curaçao, Dominican Republic, Ecuador, El Salvador, French Guiana, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Jamaica, Martinique, Mexico, Nicaragua, Panama, Paraguay, Saint Martin, Samoa, Suriname, and Venezuela

Zika virus infection was first detected in the United States territories of Puerto Rico (December 2015) and the US Virgin Islands . The first case of Zika-related congenital microcephaly in the United States was reported in January 2016 in Hawaii, in a baby born to a woman who had resided in Brazil during her pregnancy  A case of sexually transmitted Zika virus infection was reported in Texas in February 2016

Symptoms and signs of Zika virus infection typically include acute onset of low-grade fever (37.8 to 38.5°C) with maculopapular rash, arthralgia (notably the small joints of hands and feet), and nonpurulent conjunctivitis.  According to the CDC, the clinical illness is consistent with Zika virus disease if at least two  of these symptoms are present . Other commonly reported clinical manifestations include myalgia, headache, retro-orbital pain, and asthenia . More rare observed symptoms and signs include abdominal pain, nausea, diarrhea, mucus membrane ulcerations, and pruritus.

Symptoms and signs typically occur approximately 2 to 12 days after the mosquito vector bite. The illness is usually mild; symptoms resolve within two to seven days. Asymptomatic infection is common; symptoms develop in 20 to 25 percent of individuals who become infected with Zika virus. Once a person has been infected, he or she is likely to be protected from future infections . Severe disease requiring hospitalization is rare, and case-fatality rates are low .

Zika virus infection has been associated with Guillain-Barré syndrome.