West Nile Virus Spreads Rapidly Through Dutch Wild Birds as Equine Infections Continue to Rise

The Netherlands is experiencing a marked escalation in West Nile virus circulation, with wildlife rehabilitation centres reporting surging admissions of corvids and raptors showing neurological signs since early August, alongside 58 recent equine infections confirmed across multiple provinces — exposing how quickly the pathogen can establish once mosquito activity peaks.

The Dutch Wildlife Health Centre confirmed the first positive wild bird cases of the year in late July. By 11 September, Wageningen University & Research had recorded 58 horses with recent infections across provinces including South Holland, North Brabant and Gelderland.

At Vogelrevalidatiecentrum Zundert, admissions of corvids and birds of prey presenting with neurological symptoms have risen sharply since early August. Clinical options are limited: there is no antiviral therapy available, and many affected birds die despite supportive care.

The reported figures likely understate true circulation. Vogelbescherming Nederland has warned that West Nile virus can present similarly to avian influenza, requiring laboratory confirmation to distinguish between the two — meaning cases in areas without active surveillance may go unrecorded or misattributed.

Researchers are now sampling birds around Zundert to map the extent of viral circulation.

The pattern mirrors developments across Europe, where the European Centre for Disease Prevention and Control recorded 877 locally acquired human cases across 15 countries by late August. For veterinary and public health authorities, the Dutch experience underlines a One Health reality: transmission should ease as autumn temperatures reduce mosquito activity, but the season has already demonstrated how rapidly the virus moves through avian populations and into horses once vectors become active.