Uruguayan Public Health Minister Maria Julia Munoz said on Wednesday that 11 suspected dengue cases had tested negative and the nation's alert level was thus lowered to Phase 0.

Munoz spoke to the press after presenting the results of a specialist dengue laboratory in Puerto Rico.

Two weeks ago her ministry had raised the alert level to Phase 1 after tests showed a 30-year-old patient from the city of Salto, 500 km northwest of Montevideo, had contracted dengue in Uruguay.

Munoz said that new tests had showed no dengue virus in the patient and another 10 people who had symptoms of the disease that has killed 20 people and infected many more in Paraguay, Argentina and Brazil.

Dengue fever is caused by four closely-related viruses and is spread by the Aedes Aegypti mosquito, which breeds in still water. Its symptoms include high fever, nausea, rashes, backache and headaches.

Most mainstream dengue cases are not fatal, but the hemorrhagic variant, which causes severe internal bleeding as blood vessels collapse, can kill up to 20 percent of its victims.

The mosquito was eliminated in Uruguayan territory in 1958 but reappeared in 1997, as part of a broader spread across the continent that began in the 1980s.

Source: Xinhua