Zika Virus (ZIKV)

derived from host cell membranes. Viral envelope glycoproteins are embedded into the lipid membrane. The viral envelope encloses the viral capsid containing the single-stranded positive-strand viral RNA genome with a size of about 11,000 nucleotides. The genome encodes a polyprotein with a size of about 3,400 amino acids, which is processed into structural and non-structural proteins by cellular and viral proteases. The genome structure corresponds to that of other flaviviruses (5 ́-C-prM-E-NS1 NS2A NS2B-NS3, NS4ANS4B 2K NS5-3 ́). The three genes for the structural proteins (capsid (C), precursor membrane protein/membrane protein (prM/M), and envelope protein (E)) are localized at the 5 ́ end of the genome, followed by the seven genes for the non-structural proteins NS1 to NS5. These proteins have either enzymatic activity (protease, RNAdependent RNA polymerase) or are involved in the regulation of viral replication [21, 22]. The envelope protein E is necessary for the attachment to cells and their infection. In infected hosts, protein E induces neutralizing antibodies. Phylogenetic analyses of ZIKV isolates from humans, monkeys, and mosquitoes distinguish two genotypes which are endemic in Africa or Asia [15, 23–26]. Within the African genotype, a West African and an East African genotype can de differentiated [26, 27]. Dick [13] investigated the stability of ZIKV in mouse brain suspensions. He showed that virus from carefully dried brain suspensions could be re-isolated after 30 months of storage at 0–4 ° C. Treatment of a brain suspension (10%) with ether (1/1), potassium permanganate, or heat at 60 ° C for 15 min or at 58 ° C for 30 min inactivated ZIKV. Viruses in brain suspensions are rapidly inactivated by treatment with pH 6.2 or pH 7.8 [13]. Comparing these results with investigations of other flaviviruses like DENV, YFV, and WNV, ZIKV has a comparable thermal stability and sensitivity to disinfectants, alcohols, and detergents [28–30].