West Nile Virus Death in Netherlands Raises Belgian Concerns
The West Nile virus has claimed its first victim in the Netherlands, prompting Belgian health officials to warn that several cases can be expected in the country as well. The RIVM, the Dutch national institute for public health, confirmed on Wednesday that an elderly person died in the province of Utrecht after contracting the virus locally. Two other patients remain hospitalized.
A Virus Spreading Northward
The death marks a significant milestone in the virus’s northward expansion across Europe. While a first human indigenous case had already been detected in the Netherlands in 2020, this is the first fatality from the disease in the country. According to RTBF, the virus has now been found in the provinces of Utrecht, North Brabant, and South Holland so far this year.
The virus has also been detected in Belgium. In early August, a horse was euthanized in Vilvorde, near Brussels, after presenting severe neurological signs - the first confirmed equine case in the country, as RTBF reported. Several birds have also tested positive in the Antwerp region, and the city of Mechelen has alerted residents and healthcare professionals to the virus’s presence.
European Context
The European situation is concerning. As of mid-August, the European Centre for Disease Prevention and Control (ECDC) reported that West Nile virus is present in 12 European countries, with 99 regions affected, according to La Libre. Italy and Greece have recorded the most cases, with 311 and 157 respectively. Earlier in the season, the ECDC reported 241 human infections across the EU, with Italy accounting for 139 cases.
In 2025, the EU recorded 1,112 confirmed cases, with Italy and France among the hardest hit. The World Health Organization issued an alert in late July urging European countries to strengthen mosquito surveillance as conditions favorable to the virus’s spread evolve rapidly.
What Belgians Should Know
Steven Van Gucht, head of the Viral Diseases Service at Sciensano, Belgium’s public health institute, said he would not be surprised by the appearance of a human indigenous case in Belgium. “The risk is real, especially at this time of year, with a usual peak of human cases in August and early September,” he told RTBF. However, he expects isolated, sporadic cases rather than large epidemics.
West Nile virus is transmitted primarily by Culex mosquitoes, which are common in Belgium. Birds serve as the main reservoir, with mosquitoes becoming infected when feeding on infected birds. Humans and horses are accidental hosts and cannot transmit the virus to others.
About 80% of infected people show no symptoms, while approximately 19% experience flu-like symptoms. Only about 1% develop severe neurological conditions such as meningitis or encephalitis. People over 50 and those with weakened immune systems face higher risks. There is no vaccine for humans or specific antiviral treatment.
Climate Change Connection
Experts point to climate change as a key driver of the virus’s northward spread. “It is very likely that climate change contributes to the extension of the virus towards northern Europe,” Van Gucht said. Warmer temperatures favor mosquito development and allow the virus to multiply more rapidly within mosquitoes.
Dr. Hans Henri P. Kluge, WHO Regional Director for Europe, echoed this concern: “Rising temperatures and longer summer seasons give mosquitoes more time and space to transmit this virus.”
Vigilance and Prevention
Sciensano has already communicated with general practitioners and hospitals across Belgium to be alert for possible West Nile virus infections. VRT NWS reported that doctors in the Mechelen-Willebroek region have been alerted to consider the virus when faced with patients presenting unexplained flu-like symptoms.
Health authorities recommend limiting mosquito bites, especially at dusk and dawn: wearing long-sleeved clothing, using appropriate repellents, and installing mosquito screens on windows and doors. The transmission season in Europe typically runs from June to November, with peak transmission between July and September.
As the virus continues its northward march, Belgian health officials remain watchful. “We see that the virus circulates among animals and there is therefore naturally a risk that people may also be affected,” said Joris Moonens, spokesperson for the Flemish Care Department. The coming weeks, during the peak transmission period, will be crucial in determining whether Belgium records its first human case.