As Earth Warms, Virus From Tropics Moves to Italy

After a month of investigation, Italian public health officials discovered that the people of Castiglione di Cervia were, in fact, suffering from a tropical disease, chikungunya, a relative of dengue fever normally found in the Indian Ocean region. But the immigrants spreading the disease were not humans but insects: tiger mosquitoes, who can thrive in a warming Europe.

Aided by global warming and globalization, Castiglione di Cervia has the dubious distinction of playing host to the first outbreak in modern Europe of a disease that had previously been seen only in the tropics.

“By the time we got back the name and surname of the virus, our outbreak was over,” said Dr. Rafaella Angelini, director of the regional public health department in Ravenna. “When they told us it was chikungunya, it was not a problem for Ravenna any more. But I thought: this is a big problem for Europe.”

The epidemic proved that tropical viruses are now able to spread in new areas, far north of their previous range. The tiger mosquito, which first arrived in Ravenna three years ago, is thriving across southern Europe and even in France and Switzerland.