Mosquitoes’ spread poses threat beyond Zika

As the world focuses on Zika’s rapid advance in the Americas, experts warn the virus that originated in Africa is just one of a growing number of continent-jumping diseases carried by mosquitoes threatening swathes of humanity.

The battle against the insects on the streets of Brazil is the latest in an ancient war between humankind and the Culicidae, or mosquito, family which the pests frequently win.

Around the world, disease-carrying mosquitoes are advancing at speed, taking viruses such as dengue and Zika, plus a host of lesser-known ills such as chikungunya and St. Louis encephalitis, into new territories from Europe to the Pacific.

“The concern is that we have these species spreading everywhere. Today the focus is on Zika but they can carry many different viruses and pathogens,” said Anna-Bella Failloux, head of the department that tracks mosquito viruses at France’s Institut Pasteur.

In 2014, there was a large outbreak of chikungunya, which causes fever and joint pains, in the Caribbean, where it had not been seen before, while the same virus sickened Italians in 2007 in a wake-up call for public health officials.

Europe has seen the re-emergence of malaria in Greece for the first time in decades and the appearance of West Nile fever in eastern parts of the continent. The Madeira archipelago reported more than 2,000 cases of dengue in 2012, in a sign of the northerly advance of what — until Zika — has been the world’s fastest-spreading tropical disease.

In the past 40 years, six new invasive mosquito species have become established in Europe, with five arriving since 1990, driven in large part by the international trade in used vehicle tires. Mosquitoes lay their eggs in the tires and they hatch when rain moistens them at their destination.

North American health experts are also racing to keep up, with the first appearance of Aedes japonicus, an invasive mosquito, in Canada in November and Aedes aegypti found in Washington DC.

The speed of change in mosquito-borne diseases since the late 1990s has been unprecedented, according to Jolyon Medlock of Public Health England.