Two Die in Flanders From West Nile Virus

Two people in Flanders have died after becoming infected with the West Nile virus, the Flemish Department of Care (Departement Zorg) announced on 15 October. Both belonged to the risk group for a severe course of the disease, and a total of 14 confirmed infections have now been recorded in the region.

“Unfortunately, 2 people have died after infection with the West Nile virus,” said Anneleen De Sadeleer, a spokesperson for the department, as reported by VRT NWS. “Our condolences go out to their loved ones. These are people from the risk group for a severe disease course.” No further details about the deceased were released for privacy reasons.

A Rise in Confirmed Cases

Officials said the news did not come entirely unexpectedly. In mid-September, authorities had reported 10 probable or confirmed infections across Flanders and Brussels; that figure has now climbed. “14 infections have been confirmed in Flanders, of which 2 had a fatal outcome,” De Sadeleer said.

The earlier cases were concentrated in the provinces of Antwerp and Flemish Brabant - the same regions where the virus had previously been detected in horses and birds. In mid-September, VRT NWS reported that one person had been hospitalised with neurological symptoms but was recovering, while two Brussels cases were also recorded through the regional health authority Vivalis - one a local resident who was asymptomatic, the other an Italian tourist who had since returned home. No human infections have been reported in Wallonia or the German-speaking Community.

How the Virus Spreads

The West Nile virus is transmitted to humans exclusively through the bite of an infected mosquito. The insects become carriers after feeding on infected birds. Humans are what epidemiologists call “dead-end hosts” - they do not pass the virus on to one another through normal contact.

Most infections pass unnoticed. According to the VRT NWS explainer on the disease, roughly 80 percent of infected people show no symptoms. Of the 20 percent who do, most develop a mild, flu-like illness marked by fever, headache, fatigue, muscle pain, a skin rash, and swollen lymph nodes, typically appearing two to 14 days after the bite. Fewer than 1 percent progress to a severe form involving neurological complications such as encephalitis (inflammation of the brain) or meningitis (inflammation of the meninges). Elderly people and those with weakened immune systems face a higher risk.

There is no specific treatment and no vaccine; care is symptomatic, generally with pain relievers. In Belgium, the national public health institute Sciensano is responsible for the epidemiological surveillance of human West Nile fever.

Experts Link Spread to a Warming Climate

The emergence of the virus in northern Europe is not an isolated event. Researchers from the VUB and ULB universities demonstrated in a 2024 study published in Nature Communications that climate change is closely tied to the virus’s advance across southeastern Europe. WNV spread is associated with hot spring and summer temperatures, dry summers, and warm winters.

“This is the face of climate change,” climate scientist Wim Thiery of the VUB told VRT NWS. “Besides escalating climate extremes, the emergence of tropical diseases in Europe is unfortunately one of the many logical consequences of our addiction to oil, coal and gas.”

Virologist Leen Delang of KU Leuven has confirmed that Belgian mosquitoes - specifically the common house mosquito Culex pipiens - are capable of transmitting the virus. Her research group was the first to show that mosquitoes caught near Leuven could become infected and carry the virus in their saliva. Yet surveillance remains incomplete: according to former Institute of Tropical Medicine entomologist Isra Deblauwe, “We don’t yet have systematic monitoring here.”

Precautions and What to Watch For

Authorities continue to urge the public - especially the elderly and immunocompromised - to protect themselves against mosquito bites. “The vast majority of infections are mild and even asymptomatic, so they are not reported or confirmed,” De Sadeleer said. “But the elderly and people with reduced immunity remain extra vulnerable. So keep protecting yourself well against mosquito bites. The mosquito season fortunately ends in late October.”

Flemish Minister of Welfare Caroline Gennez (Vooruit) expressed her condolences to the families and called for vigilance. “Together with the Department of Care we are closely monitoring the spread of the West Nile virus,” she said. “We also call on everyone to take the necessary precautions, especially the elderly and people with reduced immunity.”

Belgium is not alone in confronting an active season. The European Centre for Disease Prevention and Control recorded 15 locally acquired human cases in Belgium and 59 in the Netherlands as of 7 October, while the Dutch public health institute RIVM reported 9 deaths in the Netherlands earlier in the season. Scientists expect the virus to keep pushing north in the years ahead.

With the mosquito season drawing to a close at the end of October, the immediate risk is expected to fall. The longer-term question - whether West Nile virus becomes a recurring summer presence in Belgium - will depend on climate trends and on whether the country closes its surveillance gap.