Concerns are mounting over the spread of West Nile virus (WNV) in Spain following the recent deaths of two more individuals in Seville, raising the nation’s death toll to five for the year. Both locals and travelers have been urged to take preventive measures, including the use of insect repellent, wearing protective clothing, and avoiding areas with stagnant water, particularly during the hours between dusk and dawn.
The rise in WNV cases is not limited to Spain. According to the European Centre for Disease Prevention and Control (ECDC), infections have also been reported across Europe in Austria, Croatia, France, Greece, Hungary, Italy, Romania, and Serbia. Notably, these cases have been confirmed as locally acquired, marking a shift from the historical pattern of infections being linked to travel in tropical regions.
This surge in West Nile virus cases follows a spring outbreak of dengue fever in Europe, which had already put travelers on high alert.
West Nile virus, a member of the Japanese encephalitis group of viruses that includes dengue and yellow fever, can lead to severe and sometimes fatal neurological disease in humans. While birds are the natural hosts of WNV, the virus is primarily transmitted to humans through mosquito bites. There have also been rare cases of transmission through blood transfusions, organ donations, and during pregnancy.
In approximately 80% of those infected, WNV does not produce symptoms. However, in the remaining 20%, the virus can develop into West Nile fever, which is characterized by a sudden high fever, headache, neck stiffness, and a rash on the neck, arms, or legs. Severe cases may result in seizures, muscle weakness, and paralysis. Those over 50 years old, especially individuals with underlying health conditions, are at greater risk of severe illness. Although less than 1% of infected individuals develop neurological complications such as meningitis or encephalitis, about 10% of these severe cases result in death.
Symptoms of WNV typically emerge two to six days after infection, though they can take up to 14 days or more to manifest. In cases without complications, symptoms generally subside within three to six days.
Currently, no vaccine exists for WNV, making prevention crucial. The ECDC advises people to avoid traveling to affected areas during peak mosquito season, typically in the summer, and to limit outdoor activities in these regions. Additional preventive measures include the use of mosquito repellent, wearing long sleeves and pants, and ensuring that living spaces are mosquito-proof.
First identified in Uganda’s West Nile district in 1937, the virus has since spread globally, with cases reported across Africa, the Middle East, West and Central Asia, North America, and Europe. As the threat of WNV continues to rise in Europe, health authorities are urging the public to remain vigilant and take all necessary precautions to protect themselves from infection.