Summer travelers to popular European destinations like Spain, France, and Italy face an increased risk of contracting deadly mosquito-borne diseases, including West Nile virus and chikungunya. Mosquito season is peaking, with soaring temperatures creating ideal breeding conditions for insects that transmit these viruses.
These diseases can cause severe symptoms ranging from debilitating joint pain and paralysis to vision loss and, in some cases, death. The viruses are transmitted when mosquitoes bite infected animals or people and then pass the pathogens to humans through subsequent bites. Last summer, over 1,000 suspected cases of these diseases were recorded across major European holiday spots, with approximately 38 fatalities, primarily from West Nile virus infections in Italy.
Official data indicates that West Nile virus is already circulating this summer. Cases have been reported in the Italian provinces of Caserta, Florence, and Verona. Romania and North Macedonia have also recorded infections. Last year, nine European countries reported a total of 652 West Nile virus infections, with Italy accounting for the majority at 500 cases.
West Nile virus, first identified in Uganda in 1937, typically circulates between birds and mosquitoes. Humans and horses can become infected if bitten by a mosquito that has fed on an infected bird. Most human infections are mild or asymptomatic, presenting as fever, headaches, or a rash. However, about one in 150 individuals develop severe complications, including meningitis and encephalitis, which can be fatal. Individuals over 50 and those with underlying health conditions like diabetes, cancer, high blood pressure, or kidney disease are at higher risk for severe illness, with the risk of death increasing for those over 70. There is no vaccine or specific treatment for West Nile virus.
Chikungunya also saw a significant surge across Europe last summer, with 301 suspected cases in France and 107 in Italy. While common in tropical regions, it has appeared more frequently in Europe. Chikungunya is known for causing intense joint pain that can persist for months or years, alongside fever, muscle aches, headaches, and fatigue. In rare instances, it can affect the eyes, brain, heart, or digestive system, with older adults and those with pre-existing conditions being more vulnerable to severe outcomes.
Dengue fever, while less common in Europe last summer with a few cases reported in France, Italy, and Portugal, is typically found in tropical areas but has increasingly been detected in parts of Europe. Symptoms include flu-like illness, but it can progress to severe dengue, characterized by intense abdominal pain, persistent vomiting, and rapid breathing. The World Health Organization estimates 100 million to 400 million dengue infections globally each year.
Experts attribute the increasing spread of mosquito-borne diseases to climate change. Professor Rachel Lowe of the Barcelona Supercomputing Center notes that global warming allows disease vectors to thrive in more regions, potentially leading to outbreaks in areas unprepared for them. Longer hot seasons create extended windows for disease transmission and more frequent, complex outbreaks.
For travelers, the primary risk of contracting these diseases comes from visiting countries where they are already circulating. While the risk of catching these diseases within the UK remains very low, health officials emphasize preventive measures such as covering up, using insect repellents, and employing mosquito nets when in affected areas. A small number of chikungunya cases are reported in the UK annually, but these are almost exclusively linked to travelers returning from endemic regions.