Health authorities have declared a red alert in Peru's northern Amazon jungle region following the outbreak of an "very aggressive" dengue strain that has killed 14 people and sickened thousands.
Dengue is endemic to the jungle region, but until now Peru has largely dealt with the American strain of the disease.
Now authorities are facing "a new variety that we did not know in Peru and that probably entered from Brazil via the Amazon," Health Minister Oscar Ugarte told local reporters on Tuesday.
There is no vaccine for dengue, a mosquito-borne viral disease.
A senior Loreto health official, Hugo Rodriguez, told AFP that this dengue strain is known as the Asian-American variety, and unlike the American variety produces severe shock among victims.
"It is a combination of both varieties," Rodriguez said, describing the strain as "very aggressive."
Health officials in Iquitos, Peru's main city on the Amazon river located some 1,000 kilometers (620 miles) north of Lima, has launched a fumigation program in an attempt to diminish the number of mosquitos.
The virus can result in deadly fevers, especially among children: half of those killed were minors.
Dengue has become a serious problem in South America.
Eight people have died of dengue since December in Bolivia, all in the Amazonian Beni region.
In Paraguay, the disease has killed five people since the start of the year, President Fernando Lugo said.
Nearly 125,000 cases were reported in Venezuela in 2010, nearly twice the figure from the previous year.
Dengue deaths are also up considerably in Brazil, local officials said, while 93 people died of dengue in Colombia in the first semester of 2010.
The disease killed nearly 1,200 people across Latin America in 2010, according to Pan American Health Organization figures.