Zika has all but disappeared in the Americas. Why?
Science Magazine - 08/16/2017
Transmission persists at low but steady levels in some parts of Latin America, including Mexico, Peru, and Colombia, agrees Alessandro Vespignani, a modeler at Northeastern University in Boston who collaborates with Longini. And recorded cases are just the tip of the iceberg because 80% of infected people have no symptoms, he says. “If the number of cases is very small, you’ll have no signal.”