West Nile virus cases reach 110 in Greece as Attica becomes epicenter of 2026 outbreak

110 cases recorded by August 12

Greece's National Public Health Organization (EODY) has recorded 110 West Nile virus infections by 12 August 2026, with 81 cases presenting Central Nervous System manifestations and 29 showing milder symptoms. The virus has been confirmed across 39 municipalities, 14 regional units, and four regions: Attica, Thessaly, Central Macedonia, and the Peloponnese. In the last week alone, 45 new domestic cases were recorded, reflecting the rapid pace of spread through August.

Attica at the epicenter

Attica, particularly its eastern portion, is the center of this year's circulation. Gikas Maiorkinis, assistant professor of Hygiene and Epidemiology, noted that the first half of August has seen the largest viral circulation this year, with Spata and Markopoulo as the most affected areas. EODY data shows 13 cases in the municipality of Spata-Artemida and 11 in the municipality of Markopoulo Mesogeas, the highest numbers among available municipal data.

Maiorkinis suggested that Storm Daniel may be one possible factor behind the increased circulation in Attica, noting that the region had no circulation in the previous four to five years. He clarified this is a possible explanation, not a confirmed causal link.

Officials warn of a difficult season

Danae Pervanidou, head of the Vector-borne Diseases Department at EODY, told ANA-MPA that if the current recording rate continues, this season may become one of the most difficult in recent years regarding case numbers. She noted that the number of cases already exceeds levels from previous years for the same period.

If the same rate of case recording continues, this year's period is predicted to be one of the most difficult periods in terms of the number of cases that will be recorded.

Historically, the peak of the seasonal outbreak is usually observed in the second half of August and may last until early or mid-September. Cases have been recorded in Greece almost every year since 2010, and EODY considers the virus established in the country.

Environmental factors and virus behavior

EODY has found no scientific evidence that the virus has changed its behavior or shows greater transmissibility compared to previous periods. This year's intensity is attributed to a complex combination of factors affecting mosquito populations, including migration routes and wild bird immunity, as well as environmental and climatic conditions.

Pervanidou highlighted elevated temperatures and rainfall as the parameters most associated with seasonal outbreaks. The warm winter of 2025-2026 in Attica, the second warmest in 150 years, may have contributed to the current epidemiological picture. Greece is listed each year among the European countries most affected by West Nile virus, usually alongside Italy and other countries in central Europe and the Balkans.

EODY expects additional cases in the coming weeks, both in areas where the virus has already been detected and in new areas whose geographic spread cannot be predicted with certainty.