WHO warns that rising temperatures and longer summers are driving an increase in West Nile virus infections across several European countries.

Europe’s scorching summer is doing more than setting temperature records. It is creating ideal conditions for West Nile virus-carrying mosquitoes to spread into more regions, prompting the World Health Organization (WHO) to issue a fresh public health warning. As human infections continue to rise across several European countries and some patients develop life-threatening neurological complications, WHO is urging people to stay informed, recognize early symptoms, and take simple measures to prevent mosquito bites before the virus spreads further (1✔ ✔Trusted Source
West Nile virus: as cases rise across parts of Europe, here is what you need to know
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The WHO said that warmer temperatures, longer summers, and changing weather patterns are extending mosquito activity and increasing opportunities for West Nile virus transmission. While the overall risk to the general population remains low, the virus can cause severe disease in a small proportion of infected individuals, particularly when it affects the central nervous system.
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WHO Reports Rising West Nile Virus Cases Across Europe
Greece has recorded the sharpest recent increase, with 21 confirmed human cases as of July 22, including 14 reported during the previous week.
Of these, 20 patients developed neuroinvasive disease, including encephalitis or meningitis, and 13 remain hospitalized.
Italy has reported the widest geographic spread, with 21 confirmed cases across 17 different areas as of July 15. Locally acquired infections have also been reported in North Macedonia (2 cases), Romania (2), and Spain (2).
The WHO noted that while the risk remains low for most people, it may turn deadly for some.
“West Nile virus is not a new threat, but the conditions driving its spread are changing rapidly,” said Dr. Hans Henri P. Kluge, WHO Regional Director for Europe.
“Most infections are mild, but roughly 1 in 150 people who contract the virus will develop a severe infection affecting the central nervous system, which can be life-threatening,” he added.
Kluge added that warmer temperatures and longer summers are giving mosquitoes more time and a wider geographic range to transmit the virus.
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How Does West Nile Virus Spread to Humans?
West Nile virus is spread primarily through the bite of an infected mosquito. Mosquitoes become infected after feeding on infected birds and can then transmit the virus to humans and other animals.
In Europe, infections typically occur during the mosquito season, from late spring through autumn, with transmission peaking between July and September.
Although rare, the virus has also been transmitted through blood transfusions, organ transplantation, pregnancy, and breastfeeding. There is no evidence of person-to-person transmission through everyday contact.
Currently, there is no licensed vaccine for humans and no specific antiviral treatment. Care focuses on relieving symptoms, while severe cases may require hospital-based supportive treatment.
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West Nile Virus Symptoms: Early Signs and Severe Warning Symptoms
Around 70–80% of infected people develop no symptoms.
Those who do become ill may experience:
- Fever
- Headache
- Fatigue
- Body aches
- Nausea or vomiting
- Skin rash
- Swollen lymph nodes
In severe cases, the infection can affect the nervous system, causing:
- High fever
- Neck stiffness
- Disorientation
- Tremors
- Convulsions
- Muscle weakness
- Paralysis
- Coma
Anyone who develops symptoms after returning from an area where the virus is circulating should seek medical attention promptly. People with severe symptoms require urgent medical care.
West Nile virus infection can be confirmed through laboratory tests that detect virus-specific antibodies or viral RNA, depending on the stage of illness.
How to Prevent West Nile Virus Infection: WHO Safety Tips
As there is no vaccine or specific treatment, WHO says prevention depends on avoiding mosquito bites and reducing mosquito breeding sites.
WHO recommends:
- Wear light-colored clothing that covers the arms and legs.
- Limit outdoor activities during dawn and dusk, when mosquitoes are most active.
- Apply mosquito repellents containing approved ingredients according to the manufacturer’s instructions. Adults should apply repellent to young children and avoid the eyes, mouth, and hands.
- Install window and door screens to keep mosquitoes out of homes.
- Sleep in air-conditioned rooms, use fans, or sleep under mosquito nets where needed.
- Eliminate standing water from flowerpots, buckets, bird baths, clogged gutters, and other containers where mosquitoes can breed.
Although most West Nile virus infections remain mild or symptom-free, the recent rise in cases serves as a reminder that simple preventive measures can make a significant difference. Staying informed, protecting against mosquito bites, and reducing mosquito breeding sites can help lower the risk of infection during mosquito season. With increased awareness and timely public health action, communities can continue to minimize the impact of this mosquito-borne disease.
Reference:
- West Nile virus: as cases rise across parts of Europe, here is what you need to know – (https://www.who.int/europe/news/item/24-07-2026-west-nile-virus–as-cases-rise-across-parts-of-europe–here-is-what-you-need-to-know)
Source-Medindia
