The virus you likely never heard of is steadily marching north from Brazil. It’s Zika, spread by Aedes mosquitoes. It’s a flavivirus related to yellow fever, West Nile, Chikungunya, and dengue. The latest two that hit the U.S., Chikungunya and dengue, are painful and bad enough—and dengue can kill people who are infected more than once. Zika adds an added nasty punch of perhaps causing microcephaly?, a birth defect where babies are born with abnormally small skulls and brains, and often have developmental abnormalities.
