The linkage of Zika viral (ZIKV) infection to microcephaly and other severe neurological impairments pose a major threat to the global public health. Currently very little is known about how ZIKV causes neural damage, and what the risk is for ZIKV-infected pregnant women in terms of their babies with microcephaly or other defects. To begin filling these gaps, we need an effective and clinically relevant in vitro ZIKV infection model. The specific objective of this pilot project is to establish such in vitro model using native human fetal brain-derived neural stem cells (NSCs). We will use this system to examine both African and Asian lineages of ZIKV, and gain insight into mechanisms underlying ZIKV-mediated neural impairments. In general terms, our central hypothesis is that ZIKV infects and adversely affects human fetal brain NSCs and their differentiated neural cells. This project will be conducted through a collaboration of multiple investigators by combining our expertise in NSCs and ZIKV, and will pursue two specific aims: 1) To characterize ZIKV infection in human fetal brain NSCs and their differentiated progenies; and 2) To characterize ZIKV-mediated changes in human fetal brain NSCs. Aim 1 will determine whether various strains of ZIKV differ in their ability to infect human NSCs and their differentiated neural cells. Particularly, this study will include a strain of Asian lineage isolated from the mosquitoes in the current outbreak in Mexico, compared to the old African strain. Aim 2 will characterize the effects of ZIKV infection on NSC proliferation, survival and differentiation. This proof-of- concept study is expected to confirm the infectiveness of ZIKV in native human fetal brain-derived NSCs and their differentiated progenies. The establishment of an effective human fetal brain NSC-based in vitro system will facilitate our efforts to dissect pathological mechanisms underlying ZIKV neurotrophism at cellular and molecular levels, to predict the risk of ZIKV neuropathogenesis, and to test potential interventions to halt and/or reverse ZIKV-associated neural damages.