Zika virus and its implication in transfusion safety

Zika virus (ZIKV), an emerging flavivirus, was initially isolated in 1947 from a Rhesus monkey in Uganda. The first evidence of human transmission of ZIKV was reported in 1952.1 Only sporadic cases of ZIKV in humans were reported in Africa and Asia before 2007, when significant outbreaks were registered outside these regions – on the islands of Micronesia, French Polynesia and New Caledonia in the Pacific Ocean.2 In Brazil, the first autochthonous ZIKV transmission was reported in the northeastern region in May 2015.3 It is believed that ZIKV was introduced in Brazil by asymptomatic travelers during the 2014 World Cup or by the World Sprint Championship canoe race.4,5 ZIKV has similar characteristics to Dengue virus in relation to epidemiology and the transmission cycle in urban environments.6 Therefore, we should expect that, due to the large distribution of the arthropod vectors (Aedes aegypti mosquitoes), the number of outbreaks and symptomatic cases might propagate. In Brazil, there are 17 officially confirmed ZIKV cases in three states: Bahia, Rio Grande do Norte and São Paulo.7 However, with the spread of ZIKV in the country, the World Health Organization (WHO) has already reported ZIKV in 14 Brazilian states including Alagoas, Bahia, Ceará, Maranhão, Mato Grosso, Pará, Paraíba, Paraná, Pernambuco, Piauí, Rio de Janeiro, Rio Grande do Norte, Roraima, and São Paulo.8 Currently, Brazil is evidencing a high number of cases of microcephaly, mainly in the northeastern part of the country, which was believed to be linked to ZIKV infection acquired during pregnancy. However, this cannot be confirmed due to insufficient scientific support as ZIKV RNA was found in the amniotic fluid of only two cases. If this condition is found to be related to ZIKV, it will represent a novel clinical manifestation of this emerging virus. Other neurological disorders correlated to ZIKV manifestations include: GuillainBarré syndrome, encephalitis, myelitis, meningoencephalitis, and optical neuritis.9 Since ZIKV is an blood-borne virus transmitted by arthropods, it represents potential risk for transfusion safety. Although the significance of ZIKV to the blood transfusion process and use of blood derivatives is currently unknown, there is a risk that ZIKV could also be transmitted by transfusions. A high number of asymptomatic blood donors was observed during the French Polynesia outbreak. However, several questions remain unclear related to the possible impact transfusion safety