An Invasive Mosquito Is Spreading With Alarming Speed, Threatening Africa’s Cities

An invasive, malaria-carrying, insecticide-resistant mosquito that thrives in cities, where malaria has not been a major threat, has moved farther and faster across Africa than even pessimistic scientists had feared. And many public health experts believe it is too late to eliminate, or even contain, it.

A new genomic analysis of the mosquito, called Anopheles stephensi, using specimens collected from 10 countries, showed that those found in Africa had genetic resistance to all of the chemicals currently used in spraying campaigns and other mosquito-control efforts, meaning those insecticides will not kill it.

It is moving with terrifying efficiency and speed across flat, open, windy terrain, pushing westward to Ghana and south through Kenya, from its initial arrival on the continent in Djibouti in the Horn of Africa more than a decade ago.