Greece has recorded 110 West Nile virus cases up to August 12 as health officials warn this season could be among the hardest in recent years. The National Public Health Organization, known as EODY, placed local authorities on heightened alert following a rapid rise in infections early in the transmission period.
Attica has registered particularly intense virus activity, although health officials confirmed the virus has not changed its behavior or shown higher transmissibility than in previous years. EODY attributed the current outbreak to environmental factors affecting mosquito populations, including an unusually warm winter.
The National Public Health Organization is the government agency responsible for monitoring communicable diseases and safeguarding public health in Greece. West Nile virus is a mosquito-borne infection transmitted to humans primarily through bites from infected Culex mosquitoes, which pick up the virus from wild birds.
Case statistics and affected regions
Official data up to August 12 shows that 81 of the 110 recorded cases involved complications affecting the central nervous system. The remaining 29 cases presented mild symptoms.
The cases occurred across 39 municipalities located in 14 regional units. Infections were reported across four administrative regions of Greece: Attica, Thessaly, Central Macedonia, and Peloponnese.
Attica recorded a particularly heavy concentration of cases across specific regional units. EODY warned that the high population density in Attica increases the risk of continued high case numbers in the coming weeks if current recording rates persist.
Environmental causes and virus behavior
In an interview with Athens-Macedonian News Agency journalist Efi Fouseki, Danae Pervanidou, head of the Department of Vector-borne Diseases at EODY, explained the drivers behind the outbreak. Pervanidou said higher temperatures and rainfall are the climate parameters most strongly linked to seasonal spikes in West Nile virus cases.
Pervanidou noted that the 2025-2026 winter in Attica was the second warmest recorded in 150 years. She said this mild winter likely contributed to the current epidemiological picture in the region.
Cases of West Nile virus infection have been reported in Greece almost every year since 2010 during mosquito circulation periods. Health officials consider the virus established in the country, making recurring seasonal outbreaks expected.
Pervanidou said the epidemiology of the virus is complex and depends on multiple natural factors. These include wild bird migration routes, bird reservoir population sizes, species diversity, immunity levels among wild birds, vector mosquito numbers, and environmental conditions that influence mosquito infection rates.
Peak timing and national surveillance
Based on historical surveillance data, health officials expect the seasonal outbreak to peak between mid-August and mid-September. Peak activity typically occurs from the second half of August through early to mid-September.
At the European level, Greece consistently ranks alongside Italy and occasionally other central European and Balkan nations as one of the countries most affected by West Nile virus in terms of case numbers and incidence per 100,000 residents.
Greece maintains an active laboratory surveillance system that requires collaborating diagnostic laboratories to report every confirmed case directly to EODY on a daily basis. EODY said this active tracking prevents under-reporting and ensures that all diagnosed cases are recorded.
EODY investigates each diagnosed case within 24 to 48 hours. The agency notifies local health units, municipalities, and regional authorities, regularly updating each municipality on its Risk Level under the national Action Plan to guide response efforts.
Public health authorities issued three press releases regarding West Nile virus this season. The agency previously issued alerts to healthcare professionals and the public in May 2026 to encourage early diagnosis and personal protection.
High risk groups and protective measures
EODY advised citizens to practice personal mosquito protection measures consistently while noting that most mosquitoes are not infected with the virus.
Health officials warned that advanced age is the principal risk factor for severe illness and potentially fatal complications. High-risk groups also include immunocompromised individuals, such as patients with lymphoma, leukemia, autoimmune disorders, organ transplants, or those taking immunosuppressive medications, alongside people with chronic medical conditions.
Personal protection guidance includes applying approved body and spatial insect repellents, such as tablets and coils, in accordance with product instructions. Citizens are advised to fit window screens, use mosquito nets, run air conditioners or fans, and wear long clothing from dusk onward when weather permits.
EODY also encouraged the public to stay informed about confirmed areas of virus circulation and exercise extra caution when living in or visiting those locations.
Eliminating mosquito breeding sites
EODY stressed that community participation is vital to destroy mosquito breeding grounds because municipal teams cannot access private property.
Property owners must inspect yards, gardens, verandas, rooftops, balconies, fields, and vacant plots regularly for standing water. Any containers holding water should be turned upside down, covered, or emptied at least once a week.
Residents should also clean rain gutters, drainage channels, and roof troughs, while sealing ventilation pipes and septic tank outlets with protective screens or mesh.
Health officials concluded that while public vigilance and consistency in applying personal protection measures are essential, there is no need for panic as national surveillance operates at its maximum level.
