Zika virus outbreak in the Americas: Is Aedes albopictus an overlooked culprit?

Azeem Mehmood Butt; Izza Nasrullah; Raheel Qamar; Yigang Tong

In a recent in silico analysis, Freire et al. reported that the codon adaptation of the ZIKV nonstructural 1 (NS1) gene is more biased towards H. sapiens than towards Ae. aegypti and suggested that this could improve viral replication within human cells (Freire et al., 2015) . This is an interesting aspect of ZIKV evolution, however, the codon adaptation index analysis was only conducted in H. sapiens and Ae. aegypti and lacked some of the recently sequenced ZIKV genomes from the outbreak regions. As ZIKV is carried and transmitted by many types of Aedes mosquitoes other than Ae. aegypti, most notably Ae. albopictus (Duffy et al., 2009) , understanding the evolutionary adaptation of viruses to their hosts and vectors is essential for developing effective surveillance, diagnostic, and preventive strategies. Based on the recently available sequence data from the outbreak and the broad range of the ZIKV vectors, we investigated the evolutionary adaptation of ZIKV to its transmission vectors and host to identify the potential cause of the ongoing massive ZIKV outbreak.