Greece has recorded its first case of West Nile virus infection of the 2026 transmission season. The patient, who is over the age of sixty, developed meningoencephalitis.
Symptoms began in late June, according to Greece’s National Public Health Organization. Health authorities identified the Municipality of Agia Paraskevi, in the Regional Unit of North Athens, as the most likely place of exposure.
The diagnosis marks the beginning of the country’s annual West Nile virus surveillance period, as mosquito activity increases during the warmer months.
More cases expected in the summer
West Nile virus infections are recorded annually in many countries worldwide, including several European nations, primarily during the summer and autumn months. Greece has reported cases during most transmission seasons since 2010. Health authorities therefore consider the re-emergence of infections during the mosquito season an expected occurrence.
However, officials cannot reliably predict where the virus will circulate or additional infections may emerge, as its spread depends on a range of environmental and epidemiological factors. Healthcare professionals across Greece were advised in May to remain vigilant for possible cases. Public guidance was also issued on measures to reduce exposure to mosquitoes.
How the West Nile virus spreads
The West Nile virus is transmitted mainly through infected mosquitoes, which usually acquire the virus after feeding on infected birds, particularly wild birds, that serve as the insects’ main natural reservoir.
Humans do not normally transmit the virus to other people through direct contact. They also do not carry sufficiently high levels of the virus in their blood to infect mosquitoes and continue the transmission cycle. Most people who contract the virus develop no symptoms. Around twenty percent may experience a mild, flu-like illness, with symptoms including fever, headache, fatigue, muscle pain, nausea, or a skin rash.
Fewer than one percent of infected people develop severe disease affecting the central nervous system, including meningitis, encephalitis, or acute flaccid paralysis. Older adults, people with weakened immune systems, and those with chronic underlying health conditions face a higher risk of severe illness and potentially life-threatening complications.