The National Public Health Organization of Greece (EODY) has confirmed the first recorded cases of West Nile virus infection for the 2025 transmission season. Four cases were diagnosed within a 48-hour period in the greater Athens region, specifically in the municipalities of Aspropyrgos, Korydallos, and Salamina. These areas fall within the broader regional units of Western Attica, Piraeus, and Islands.
Cases Affecting Older Adults
The infections involved individuals over the age of 65 who exhibited symptoms of encephalitis or meningoencephalitis. According to EODY, these patients developed symptoms in the last ten days of June 2025. The agency continues to monitor the situation closely, stressing that the appearance of such cases during summer and autumn is not unusual and occurs annually in several countries, including Greece.
Since 2010, Greece has seen recurring outbreaks almost every year, making the reemergence of West Nile virus during the warmer months an expected event.
Prevention and Public Awareness
In anticipation of this year’s transmission season, EODY issued guidance in May 2025 to healthcare professionals nationwide, urging increased vigilance. A public information bulletin followed in June, recommending personal protection measures to reduce exposure to mosquito bites.
While the geographical spread of the virus cannot be predicted, EODY advises residents and visitors throughout the country to take consistent protective steps, including:
- Using approved mosquito repellents for both body and living spaces.
- Installing window and door screens, using mosquito nets, and employing fans or air conditioners.
- Wearing long, protective clothing during mosquito-active hours.
- Eliminating standing water in outdoor spaces to reduce mosquito breeding grounds.
Elderly individuals, people with weakened immune systems, and those with chronic illnesses are urged to be especially diligent, as they are at higher risk of developing serious illness.
Virus Transmission and Health Risks
The West Nile virus is primarily spread through the bite of infected common mosquitoes, which acquire the virus from wild birds. Humans do not transmit the virus further, either to mosquitoes or to other people through direct contact.
Most people infected with West Nile virus do not experience symptoms, or only show mild signs of illness. However, fewer than 1% may develop serious complications affecting the nervous system, such as encephalitis or meningitis.
National Response and Monitoring
EODY conducts enhanced epidemiological and entomological surveillance across Greece to enable early detection and targeted interventions. Surveillance has been significantly strengthened in recent years.
In collaboration with local authorities, EODY also investigates reported cases and publishes weekly updates every Wednesday, detailing the number of infections by municipality. This allows the public to stay informed about the regions where the virus is known to be circulating.
The Greek Ministry of Health has implemented a National Action Plan for managing West Nile virus outbreaks. This plan outlines standardized response measures and includes risk assessments and designation of high-risk zones by an intersectoral working group. An updated list of affected areas is regularly posted on EODY’s official website.
As the transmission season unfolds, public cooperation and awareness remain vital to minimizing health risks and limiting the spread of the virus.
