West Nile virus detected in a blood donor

A West Nile virus infection has been confirmed in a blood donor in the Netherlands. This occurred in August 2026 during a Sanquin study among blood donors from areas where the West Nile virus had previously been detected in humans, horses, birds or mosquitoes. A laboratory test (PCR) detected the virus in the donor, who had no symptoms and is still not showing any. The person lives in the province of Utrecht and has not been abroad recently. It is therefore likely that the infection was contracted in the Netherlands.