Neurological disease caused by flavivirus infections

Abstract

Epidemics and localised outbreaks of infections due to arthropod borne (arbo) viruses, have been described for hundreds of years. Few viruses to date are known to transmit from mother to fetus, causing either teratogenic effects or fetal demise (see recent reviews Charlier et al.1 and Marinho et al.2). Many arboviruses are zoonotic but there appear to be few parallels between the effect of these viruses following human or animal infection during pregnancy. Higher rates of MTCT (mother to child transmission) may be seen (1) where herd immunity is reduced, either because virus is newly introduced into a population (as occurred in Brazil with ZIKV), or where the virus has only recently become endemic (as occurred with West Nile virus (WNV) in the USA in the 1990s), (2) where the arthropod vector is present, (3) where the vector transmits virus efficiently, and (4) in groups of pregnant women exposed, allowing transmission3.