West Nile virus infections claim nine lives this year
RIVM reports 56 infections probably contracted in the Netherlands and expects the outbreak’s peak to have passed.
Nine people have died in the Netherlands this year after a West Nile virus infection, RIVM reports. Up to and including 30 September, the institute recorded 56 infections probably contracted in the Netherlands, but is seeing the number of new infections decline.
RIVM bases the figures on reports from doctors, laboratory testing and research involving animals and mosquitoes. Human infections have been identified in Zuid-Holland, Utrecht, Noord-Holland, Noord-Brabant, Gelderland and Overijssel. Most patients were examined after being admitted to hospital with symptoms.
The virus is spread by the common house mosquito. It can pick up the virus from infected birds and then transmit it to people or horses. People and horses can become infected, but are considered dead-end hosts: they generally do not spread the virus further.
According to RIVM, around 80 per cent of infected people develop no symptoms. A smaller proportion develop mild, flu-like symptoms. In around 1 per cent, a serious neurological condition may develop. According to the institute, the risk of becoming infected and ill in the Netherlands remains small, despite this year’s exceptional increase.
The nine deaths must be interpreted carefully. When deaths are reported in combination with the virus, doctors investigate whether the virus was the direct cause of death. In some patients, other serious conditions also play a role. RIVM therefore presents the figure as deaths among people with an infection, not automatically as nine deaths caused solely by the virus.
New infections have also been found in animals. According to RIVM and NVWA, the number of horses testing positive reached 150 in 2026. There were 178 reports involving birds; four positive mosquito pools had been found. Birds from the crow family in particular appear to be vulnerable.
RIVM expects the peak of this outbreak to have passed because the number of new infections has declined in recent weeks. This is an assessment of the current development, not a prediction that new infections are impossible. Surveillance will continue during the mosquito season.
Since August, Sanquin has been testing blood donations from areas where the virus is circulating. The reason is that West Nile virus can, in exceptional cases, be transmitted through blood. Health information changes regularly; this report describes the situation according to the RIVM update of 1 October 2026 and is not individual medical advice.
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The figures and medical context were checked against the RIVM update and additional explanations from RIVM. The text avoids the incorrect conclusion that all nine deaths were caused solely by the virus.
- confirmed RIVM reported 56 infections probably contracted in the Netherlands. — This is stated in the RIVM update of 1 October 2026. source
- confirmed In 2026, nine patients with a West Nile virus infection died. — RIVM explicitly gives this figure, with the qualification that the direct cause of death may differ. source
- confirmed Around 80 per cent develop no symptoms and around 1 per cent develop serious neurological symptoms. — These proportions appear on the general RIVM information page. source
- confirmed RIVM expects the peak to have passed. — The expectation appears in the update of 1 October. source
- confirmed There were 150 positive horses and 178 positive birds reported. — These totals appear in the animal section of the RIVM update. source
Editor's note
The figures are snapshots from the RIVM update of 1 October. The number of deaths among infected people is not the same as an established direct cause of death in every individual case.Sources
More on this in Dutch media
- NRC — „westnijlvirus r ivm”
- NU.nl — „westnijlvirus r ivm”
- De Telegraaf — „westnijlvirus r ivm”