The World Health Organization (WHO) has issued a warning about the rapid spread of the potentially fatal West Nile virus across popular European travel destinations. The organization is urging both tourists and locals to take measures to prevent mosquito bites, the primary mode of transmission.
Greece has reported a significant increase in cases, with 21 human infections confirmed as of July 22, 14 of which were recorded in the preceding week. Of these, 20 patients developed neuro-invasive disease, including encephalitis or meningitis, and 13 remain hospitalized. Italy has the broadest geographic distribution, with 21 cases confirmed across 17 different areas as of July 15. Locally acquired cases have also been reported in Spain, Romania, and North Macedonia.
West Nile virus is acquired by mosquitoes feeding on infected birds. While most human infections occur through mosquito bites, transmission has also been documented through organ transplants, blood transfusions, pregnancy, and breastfeeding.
Dr. Hans Henri P Kluge, WHO regional director for Europe, stated that while West Nile virus is not a new threat, the conditions facilitating its spread are rapidly changing. He attributed this to warmer temperatures and longer summers, which provide mosquitoes with more time and territory to transmit the virus. "Most infections are mild, but roughly 1 in 150 people who contract it will develop a severe infection affecting the central nervous system which can be life-threatening," Kluge said.
Symptoms of West Nile virus infection can include high fever, neck stiffness, disorientation, tremors, convulsions, muscle weakness, paralysis, or coma in severe cases. Between 70% and 80% of infected individuals develop no symptoms. Those who do may experience fever, headache, fatigue, body aches, nausea, or vomiting, and sometimes a rash or swollen lymph glands.
There is no licensed vaccine for humans, nor are there specific antiviral drugs. Treatment focuses on managing symptoms and providing supportive care in hospitals for severe cases affecting the central nervous system. The WHO advises that anyone developing symptoms after returning from an affected area should seek prompt medical attention, and those with severe symptoms should do so immediately.
The WHO is urging countries to enhance mosquito surveillance and public awareness of protective measures. Recommendations include wearing light-colored clothing that covers most of the body, using insect repellent with approved active ingredients, and limiting outdoor activities during dawn and dusk when mosquitoes are most active. The organization also advises installing screens on windows and doors, using mosquito nets, and eliminating stagnant water sources around homes and public areas, as these serve as common breeding sites for mosquitoes.
Human infections typically occur during the mosquito season, from late spring through autumn, with peak transmission usually observed between July and September.