Four people lost their lives this week for complications after contracting the West Nile virus, bringing the death toll across Greece from the beginning of the year so far to 31, according to the Greek authorities.

According to the weekly epidemiological surveillance report of the Hellenic Center for Disease Control and Prevention (KEELPNO), the reported cases have reached 271 this year until Saturday.

Twenty one patients are currently hospitalized, including 14 in intensive care.

The virus which is transmitted by mosquitoes' bites can affect the nervous system and cause meningitis, encephalitis and other serious complications.

It was first detected in Greece in 2010, with 262 confirmed cases and 35 deaths. In 2017 Greece reported five fatalities.