RIVM reports 44 West Nile virus infections in the Netherlands
Sixteen new patients have been added since the previous update; five deaths were reported in 2026.
There is news on this story (Thursday, 1 October 2026, 14:03): Four patients with West Nile virus have died
The RIVM reported 44 confirmed West Nile virus infections in the Netherlands up to and including 23 September. Sixteen patients have been added since the previous update, bringing the total number of reported deaths to five.
The figures appear in the RIVM’s weekly update. All sixteen newly reported patients are thought to have contracted the virus after being bitten by an infected mosquito. According to the institute, most patients were examined after being admitted to hospital with symptoms.
The reports came from six provinces. Zuid-Holland recorded 23 patients, Utrecht ten, Noord-Holland and Noord-Brabant four each, Gelderland two and Overijssel one. The RIVM stresses that the actual number of infections may be higher, as many infected people develop no symptoms or are not tested.
West Nile virus circulates among birds and can be transmitted to humans and horses by the common house mosquito. Humans and horses do not spread the virus further via mosquitoes. According to the RIVM, around 80 per cent of infected people develop no symptoms; a smaller proportion develop flu-like symptoms.
Severe illness is uncommon according to the institute, but can include encephalitis or meningitis. Older people and those with weakened immune systems in particular have a higher risk of becoming seriously ill. The RIVM provides general information and does not comment on the treatment of individual patients.
The number of reports among animals also increased. In the same update, the Netherlands Food and Consumer Product Safety Authority reported 136 horses with a positive test in 2026. In addition, 171 infected birds and four positive mosquito traps had been recorded.
The institute publishes new figures weekly during the mosquito season. These figures are a snapshot and do not directly indicate how many people are infectious at that time. For the Netherlands, the key point is that the virus has now been detected in several locations among humans, birds, horses and mosquitoes.
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The figures and provinces were checked directly against the RIVM update. Medical information has been kept general and has not been turned into personal treatment advice.
- confirmed Up to and including 23 September, 44 human West Nile virus infections had been reported. — This is the total in the RIVM update of 24 September. source
- confirmed Sixteen patients have been added since the previous update. — The RIVM update names sixteen new patients. source
- confirmed Five deaths were reported in 2026 among people with a West Nile virus infection. — This appears in the same RIVM update. source
- confirmed Around 80 per cent of infected people develop no symptoms. — The RIVM gives this as general epidemiological information. source
Editor's note
The most recent RIVM update found runs up to and including 23 September 2026. The figures are reports of confirmed infections, not an estimate of all infections.Sources
The story so far
- Thursday, 1 October 2026, 11:26 RIVM reports 44 West Nile virus infections in the Netherlands (this article)
- Thursday, 1 October 2026, 12:02 New deaths from West Nile virus not yet officially confirmed
- Thursday, 1 October 2026, 13:02 Number of Dutch West Nile cases rises to 56
- Thursday, 1 October 2026, 14:03 Four patients with West Nile virus have died
More on this in Dutch media
- AD — „westnijlvirus westnijlkoorts”
- de Volkskrant — „westnijlvirus westnijlkoorts”
- RTL Nieuws — „westnijlvirus westnijlkoorts”