BELGRADE, Aug. 7 (Xinhua) -- Nine deaths related to the West Nile Virus have been reported in Serbia since the beginning of the mosquito season, four of which occurred in the past week, the Institute of Public Health of Serbia stated in a press release on Tuesday.

The release reads that the virus was confirmed in the population of mosquitoes in northern parts of Serbia, especially in Belgrade, where all four fatal outcomes occurred.

The institute said that out of 102 cases of West Nile infection this season, 44 were registered in Belgrade, as the mosquitoes carrying the virus in Serbia are most densely populated around the confluence of the Danube and Sava rivers.

The press release said that from the first confirmed West Nile infection in 2012 to the end of 2017, a total of 574 infections were reported in Serbia, 61 of which were fatal.

In European Union (EU) countries, 111 cases of the virus -- mostly in Italy and Greece -- have been reported so far in 2018. Last year there were 340 reports of infection, resulting in 35 deaths.

The West Nile Virus is transmitted by mosquitoes and maintained among birds. Besides humans, the virus is also present in horses.

Eighty percent of people infected with the virus have no symptoms, while 20 percent report a flu-like state. The virus is life-threatening for the elderly.

In less than one percent of people, the virus causes aseptic meningitis or encephalitis which require hospitalization. These patients report headaches, a stiff neck, disorientation, weakness and depression.

The institute urges people to use prevention against mosquitoes in order to reduce the risk of catching the virus.