The National Public Health Organization (EODY) informs that the first case of West Nile virus infection for the 2023 transmission period has been diagnosed in our country, in the Regional Unit of Serres (Municipality of Heraklion).

West Nile virus is mainly transmitted by the bite of infected “common” mosquitoes, which are infected by infected birds (certain species mainly wild birds). Infected humans do not further transmit the virus to other mosquitoes.

The majority of people infected with the virus do not get sick at all or only have mild disease, while a very few people (<1% of those infected) develop severe disease that affects the nervous system (mainly encephalitis or meningitis). Older people (over 50 years old) are more at risk of becoming seriously ill, as well as people with immunosuppression and chronic underlying diseases.

Health professionals on alert

Outbreaks of West Nile virus infection occur in many countries worldwide, as well as in many European countries, on an annual basis. From 2010 onwards, cases appear almost every year (and) in our country, in various regions, during the summer and autumn months. Therefore, reoccurrence of cases in each transmission period is expected. In May 2023, the EODY informed health professionals nationwide about the need to be alert for the disease and issued a relevant Press Release to inform the public, with recommendations for taking preventive measures against mosquitoes.

In each period of transmission, with the aim of the timely implementation of targeted response and prevention measures, the EODY carries out enhanced epidemiological surveillance of the disease, immediately investigates the incidents and is in constant communication and cooperation with the competent national, regional and local authorities.

Individual protection measures

As the epidemiology of the virus is determined by many factors, the areas of virus circulation and outbreaks cannot be predicted with certainty. Therefore, EODY recommends that individual protection measures against mosquitoes be observed, throughout the territory, throughout the mosquito circulation period. Specifically it states:

• Use approved body and environmental insect repellents (according to the instructions for use), screens, mosquito nets, air conditioners/fans, suitable (long) clothing.

• Do not leave stagnant water anywhere (thus effectively helping to limit mosquito breeding grounds in private areas).

Older people and people with chronic underlying diseases should take their measures with particular consistency.

More information on West Nile virus and mosquito protection measures can be found on the EODY website (, where – also – every A weekly report with updated epidemiological data will be posted on Tuesday.