The cyanobacterial saxitoxin exacerbates neural cell death and brain malformations induced by Zika virus

Abstract

The hypothesis that saxitoxin (STX), a neurotoxin produced in South America by thefreshwater cyanobacteria Raphidiopsis raciborskii, could have contributed to the mostsevere Congenital Zika Syndrome (CZS) profile described worldwide. Quality surveillanceshowed higher cyanobacteria amounts and STX occurrence in human drinking water suppliesof NE compared to other regions of Brazil. Experimentally, we described that STX doubledthe quantity of ZIKV-induced neural cell death in progenitor areas of human brainorganoids, while the chronic ingestion of water contaminated with STX before and duringgestation caused brain abnormalities in offspring of ZIKV-infected immunocompetentC57BL/6J mice. Our data indicate that saxitoxin-producing cyanobacteria is overspread inwater reservoirs of the NE and might have acted as a co-insult to ZIKV infection in Brazil.These results raise a public health concern regarding the consequences of arbovirus outbreakshappening in areas with droughts and/or frequent freshwater cyanobacterial blooms.