As summer temperatures linger across the Mediterranean, health authorities are warning of a rise in West Nile virus cases. The transmission season, which typically runs from late spring to autumn, peaks between July and September. This year, confirmed infections have been reported in Greece, Italy, Spain, Romania, and North Macedonia, prompting the World Health Organization (WHO) to issue fresh prevention advice.
“Simple steps like covering up, using insect repellent and clearing stagnant water around the home can make a real difference,” said Hans Henri P. Kluge, WHO Regional Director for Europe, on Friday. There is currently no licensed vaccine for humans, and treatment is limited to managing symptoms and providing supportive care in hospital for severe cases.
How to reduce your risk
WHO Europe recommends covering most of the body with long sleeves and trousers, especially during dawn and dusk when mosquitoes are most active. Applying insect repellent, installing window and door screens, and using mosquito nets over beds and baby carriers are also advised. Clearing stagnant water from pots, containers, and other waste removes breeding sites and lowers local transmission risk.
In a related development, West Nile Virus Spreads Across Southern Europe: 21 Cases in Greece highlights the sharp increase in infections there. Greek authorities reported 21 confirmed human cases as of 22 July, with 20 of those patients developing neuroinvasive disease such as encephalitis or meningitis. Thirteen remain hospitalised.
Italy has recorded the widest geographical spread, with 21 confirmed cases across 17 separate areas as of 15 July. Locally acquired infections have also been confirmed in North Macedonia (two cases), Romania (two), and Spain (two).
Symptoms to watch for
Most people infected with West Nile virus—around 70 to 80 percent—develop no symptoms. Those who do may experience fever, headache, fatigue, muscle aches, nausea or vomiting, and sometimes a rash or swollen lymph nodes. “Anyone who develops a high fever, rash or neck stiffness after a mosquito bite should see a doctor without delay,” Kluge said. Around one in 150 infected people develops severe disease affecting the central nervous system, “which can be life-threatening,” he added.
Climate change fuels spread
Warmer temperatures and longer summers are giving mosquitoes more time and territory to transmit the virus. “West Nile virus is not a new threat, but the conditions driving its spread are changing rapidly,” Kluge noted. As global warming continues, the transmission season is expected to lengthen and expand northward, affecting regions previously considered low-risk.
For travellers heading to southern Europe this summer, taking these precautions is essential. The virus is primarily transmitted through the bite of infected Culex mosquitoes, which breed in stagnant water. While most infections are mild, the potential for severe neurological complications means vigilance is warranted.
For more on how to stay safe while exploring the continent, see How to Rediscover Travel's Element of Surprise in the Age of Social Media. Meanwhile, the broader health landscape in Europe faces other challenges, as Antibiotic-Resistant Gonorrhea Cases Surge Across Europe, ECDC Warns of Local Spread underscores the need for continued public health vigilance.
