Four municipalities in Crete are now on the EODY list of areas classified as affected or high-risk for West Nile virus: Rethymno, Archanes-Asterousia, Heraklion, and Hersonissos. Hersonissos is classified as a high-risk area, while the other three are classified as affected areas.
Greece’s National Public Health Organization (EODY) has updated its list to cover 99 municipalities nationwide. The latest official update, dated September 24, 2026, includes human cases reported during the current transmission season, along with epidemiological, entomological, and geographical data.
For Crete, the four municipalities are:
| Rethymno | Rethymno | Affected |
| Heraklion | Archanes-Asterousia | Affected |
| Heraklion | Heraklion | Affected |
| Heraklion | Hersonissos* | High risk |
The asterisk beside Hersonissos in the EODY list means no recent human case has been recorded there during the current 2026 transmission period, but the municipality is classified as high risk because of a combination of current and historical epidemiological information, mosquito surveillance, and geographical factors.
What “Affected” Means
EODY defines an affected municipality as one where at least one human case of West Nile virus infection has been recorded recently during the current 2026 transmission period.
In Crete, that applies to Rethymno, Archanes-Asterousia and Heraklion.
What “High Risk” Means
A high-risk municipality is different. It does not necessarily mean that a human case has been recorded there.
Instead, EODY identifies municipalities with no human cases this season but where several factors point to potential transmission. These can include proximity to affected areas, geographical characteristics, current and historical epidemiological information, and evidence of virus circulation in mosquitoes or animals.
That is the classification currently given to Hersonissos.
The Rest of Greece
The updated list extends well beyond Crete.
It includes municipalities across Attica, Thessaly, Central Macedonia, Pieria, Kilkis, Chalkidiki, the Peloponnese, Central Greece, Eastern Macedonia and Thrace, the South Aegean and the Ionian Islands.
The listed areas include municipalities in and around Athens and Piraeus, as well as Larissa, Karditsa, Trikala, Thessaloniki, Veria, Edessa, Olympia, Alexandroupoli, Komotini, Tinos, and Lefkada.
The classification is not a permanent designation. It reflects the assessment for the 2026 transmission period and can change as new epidemiological and surveillance information becomes available.
Why EODY Is Publishing the List
The “affected” and “high-risk” classifications are used primarily for blood safety and haemovigilance. These areas also apply additional measures to reduce the risk of West Nile virus transmission through blood transfusion.
The list should therefore not be read as a simple map of places where people should not travel.
At the same time, EODY stresses that it cannot predict with certainty where West Nile virus will circulate or where new human cases will appear. The organization recommends mosquito-bite protection throughout Greece during the mosquito season, with particular consistency in areas where recent cases have been recorded.
Crete: The Practical Message
For anyone living in or visiting Rethymno, Heraklion, Archanes-Asterousia or Hersonissos, the sensible takeaway is not panic. It is mosquito protection.
EODY recommends measures such as avoiding mosquito bites and reducing mosquito exposure around homes. The organization also notes that older people and people with immunosuppression or chronic underlying conditions face a higher risk of severe disease and should take particular care to avoid mosquito bites.
West Nile virus is transmitted mainly through bites from infected mosquitoes. EODY says that most infected people develop no symptoms, while a small proportion develop severe disease affecting the nervous system.
For Crete, the headline is therefore quite straightforward: Four municipalities are now on the EODY list, three as affected areas and Hersonissos as high risk.
And with mosquito activity continuing into the autumn, the advice remains the same across the island: repellent, appropriate clothing, screens where possible and fewer opportunities for mosquitoes to make you dinner.
