West Nile virus is a mosquito-borne disease usually found in temperate and tropical regions. While many cases are mild and have no symptoms, severe disease symptoms can include headaches, high fever, neck stiffness, coma, tremors, convulsions, muscle weakness and paralysis.

Kosovo confirmed its first fatality on Wednesday, saying the victim was a woman from central Kosovo who died on Sept 14. Macedonia's health officials said on Thursday one woman had died and two other people were infected with the virus.

A spokesman for the Kosovo Health Ministry told Reuters on Thursday two other people who died recently were also suspected of having the same virus, but the cases had not been confirmed with laboratory blood tests.

The United States is currently experiencing one of its worst outbreaks of West Nile virus since 2003.

In Serbia, three people have died and 35 were hospitalized since mid-August.

"This is the first time the West Nile virus has been officially registered in Serbia," the country's Department for Public Health said in a statement.

All the infected people were over 50 and had other chronic diseases, it said. Serbia's western neighbor Croatia has registered five probable cases of the virus but no deaths.

(Reporting by Fatos Bytyci in Kosovo, Aleksandar Vasovic in Serbia, Kole Casule in Skopje and; Zoran Radosavljevic in Croatia; Editing by Sophie Hares)

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