West Nile virus infections confirmed in nine people in the Netherlands

**West Nile Virus Confirmed in Nine People in the Netherlands Since Summer’s Start**

*The National Institute for Public Health and the Environment (RIVM) reported that nine individuals have been diagnosed with West Nile virus (WNV) in the Netherlands from the beginning of the summer through early September 2026.*

The infections were identified across four provinces—Utrecht, North Brabant, North Holland and South Holland—with at least one case linked to the Amsterdam region in the past week. According to the RIVM, the cases were confirmed after patients were hospitalized with symptoms, except for one individual detected through a blood‑donor screening study conducted by Sanquin Research.

The virus is known to be circulating in the country, as indicated by ongoing surveillance of birds and mosquito populations. Sanquin Research and the RIVM have reported that two separate mosquito groups tested positive for WNV, and three mosquito pools were found to carry the virus in the previous year.

One of the nine patients has died. The regional public health office of Drenthe (GGD Drenthe) indicated that a woman from the province may have succumbed to the infection in early August; she had reportedly contracted the virus during travel to southeastern Europe, where her symptoms first appeared.

Since the first human case was recorded in October 2020, the Netherlands has seen sporadic infections. No human cases were reported in 2025. In addition to human cases, the Netherlands Food and Consumer Product Safety Authority (NVWA) is investigating five cases of WNV in horses this year, an increase from three cases in 2023. Bird surveillance has identified six additional infections in 2026, slightly fewer than the seven reported in 2025.

The RIVM notes that approximately 1 % of people infected with WNV develop severe disease such as encephalitis or meningitis, with a mortality rate ranging from 4 % to 14 % among those patients. The risk of death is roughly double for individuals aged 70 years or older. Around 20 % of infected persons experience mild, flu‑like symptoms, including headache, fever, muscle aches, gastrointestinal upset, and occasionally skin rash or swollen lymph nodes.

A multidisciplinary team comprising doctors, veterinarians, virologists, epidemiologists and ecologists is monitoring the situation and coordinating response measures, according to the RIVM.

Article and image source: nltimes.nl