ABOVE: Droughts in northeastern Brazil indirectly led to increased incidence of microcephaly in babies born during the Zika epidemic, a study suggests.
© WIKIMEDIA, MARCELLO CASAL JR/AGÊNCIA BRASIL
For four years starting in 2012, dry weather crackled across northeastern Brazil. Temperatures rose, vegetation died, and fresh water started to evaporate more quickly from the region’s reservoirs. Though the conditions were devastating for local human populations, they were ripe for bacterial blooms to flourish in the water. Among the bacterial species known to establish themselves in reservoirs and wells during such droughts is the cyanobacterium Raphidiopsis raciborskii.
More often than not, the strain of R. raciborskii that colonizes reservoirs and wells in the region is one that secretes saxitoxin, a chemical that lets the bacterium thrive in the salty, mineral-rich water associated with dry spells. Although saxitoxin aids the bacterium’s survival, it is—as its name indicates—toxic to humans, who often ingest it ...
