West Nile virus affects Swiss blood supply

The virus can be passed through mosquito bites and blood transfusions. Keystone / Patrick Pleul

Travellers who spend at least 24 hours in certain southern European countries face restrictions when donating blood in Switzerland.

The reason is the increase in cases of West Nile virus, which has been recorded in neighbouring France and Italy as well as southeastern European countries.

Swiss health authorities have introduced a 30-day waiting period for potential donors who have just returned from a country where the virus has been reported. The virus spreads via migratory birds and local mosquitoes. The incubation period is ten days, and infected people often show no symptoms.

“The blood donor can be symptom-free, but still be carrying the virus and pass it on through the blood donation. This can cause illness and serious complications for the recipient,” Beat Frey, head doctor at Zurich’s Red Cross blood centreExternal link, told Swiss public television, SRFExternal link.

So far there have been no reports of West Nile virus in Switzerland this year. If five cases are reported, the Federal Office of Public HealthExternal link will require that every blood donor be tested.