PANIC started to spread through the village of Castiglione di Cervia in Italy in August as one person after another fell ill with weeks of high fever, exhaustion and excruciating bone pain, just as most of the nation was enjoying Ferragosto, its most important summer holiday.
By the middle of the month, more than 100 people had come down with the same illness. Although the worst symptoms dissipated after a couple of weeks, doctors were unable to diagnose what was wrong.
Antonio Ciano, 62, recalled: "At one point, I si
mply couldn't stand up to get out of the car. I fell. I thought, OK, my time is up. I'm going to die. It was really that dramatic."
River pollution was blamed. People denounced the government. But most of all they blamed recent immigrants from tropical Africa for bringing the pestilence.
"Why immigrants?" asked Rina Ventura, who owns a shoe shop: "I kept thinking of these terrible diseases that you see on TV, like malaria. We were terrified. There was no name and no treatment."
The villagers were both right and wrong. After a month of investigation, Italian public health officials discovered that the people of the village, population 2,000, were, in fact, suffering from a tropical disease, chikungunya, a relative of dengue fever normally found in the Indian Ocean region. However, the immigrants spreading the disease were not humans, but insects: tiger mosquitoes, who can thrive in a warming Europe.
Aided by global warming and globalisation, 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.
From the start, doctors suspected that the disease was spread by insects, rather than people. While almost all homes had one person who was ill, family members seemed not to catch the disease from one another.
"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.
Dr Angelini added that if chikungunya can spread to Castiglione, there is no reason why it cannot go to other Italian villages. There is no reason why dengue, an even more debilitating tropical disease, cannot as well.
Dr Roberto Bertollini, the director of the World Health Organisation's health and environment programme, said: "This is the first case of an epidemic of a tropical disease in a developed, European country. Climate change creates conditions that make it easier for this mosquito to survive and it opens the door to diseases that didn't exist here previously. This is a real issue. Now, today. It is not something a crazy environmentalist is warning about."
With climate change at hand, Dr Bertollini said, chikungunya will surely be back somewhere in Europe again.
BLOOD RELATIVECHIKUNGUNYA is spread when tiger mosquitoes drink blood from an infected person and, if conditions are right, pass the virus on when they bite again.
Tiger mosquitoes first came to southern Italy with shipments of tyres from Albania about a decade ago, and their habitat has expanded steadily north as temperatures have risen. But the doctors were baffled by how the virus made its way into mosquitoes in northern Italy since no-one in Castiglione di Cervia had been abroad. Eventually investigators discovered a link: one of the first men to fall ill in Castiglione di Cervia had been visited by a feverish relative in early July. That relative, an Italian, had previously travelled to Kerala, India.
Chikungunya came to Italy in his blood, but climatic conditions are now such that it can spread and find a home .
