Italian scientists are sounding an alarm over a surge in cases of dengue fever cases in the country's central Marche region, as high temperatures have encouraged the spread of the virus.
The disease, also known as "break-bone fever" for the severity of the pain and spasms experienced by some patients, is transmitted by certain types of mosquitoes.
It causes millions of infections each year and tens of thousands of deaths in Asia and Latin America. It is also spreading to southern Europe, with Italy recording 500 cases so far this year, according to the National Health Institute.
A cluster of infections in the small town of Fano has seen more than 100 confirmed cases since mid-August, 35 of which required hospitalization, authorities said, adding that another 10 suspected cases are awaiting confirmation.
The large northern region of Lombardy, around Milan, was the hardest hit in Italy last year with fewer than 80 cases.
The country has registered no deaths this year, but doctors are concerned that the picture may be worse than it seems, with many asymptomatic cases going unreported.
"The situation is out of control, infections are at least double (those officially reported). Let's hope the winter comes soon," Roberto Burioni, professor of virology at Milan's San Raffaele university, posted on Facebook.
Scientists are still trying to understand why Fano, a coastal town of 60,000 people on the Adriatic coast, should have been so badly affected.
"Fortunately, the infection area is very small, because mosquitoes have a limited movement of 200 metres," said Flavia Riccardo, research manager at the Infectious Disease Department of the National Health Institute.