Europe review spotlights horses in West Nile surveillance
A new review in Pathogens is making the case that Europe should treat horses as a more central part of West Nile virus surveillance, not just as occasional clinical cases. Published in March 2026, the paper examines how the virus is behaving across Europe and argues that equine sentinel surveillance can strengthen One Health detection systems as West Nile activity expands into new regions. (mdpi.com)
That argument lands against a backdrop of steady geographic change. The review describes a progressive northward expansion of West Nile virus in Europe, linked to growing climatic suitability and shifts in vector ecology, including the establishment of Culex pipiens and Culex modestus in parts of central and northern Europe. By 2023, more than 20 European countries had reported West Nile virus in humans, horses, or wildlife. EU surveillance has also become more structured: EFSA and ECDC jointly track infections in humans, equids, and birds, while outbreaks in animals are reported through the Animal Disease Information System under EU notification rules. (mdpi.com)
The review’s core point is that horses can provide actionable surveillance value because they share environmental exposure with people, yet are often sampled in ways that help define where the virus is circulating. The authors write that unvaccinated horses are recommended as sentinel species in endemic and newly affected areas, and they conclude that serological surveillance in horses can mirror local circulation and sometimes provide the earliest sign of transmission. A recent One Health study from the Barcelona metropolitan area supports that idea: horse IgM findings helped define the circulation zone and suggested viral activity occurred before, or at least alongside, human and bird detections in that setting. (mdpi.com)
The broader surveillance picture suggests the issue is not theoretical. EFSA’s most recent monthly report for the 2025 season said that, as of December 3, 2025, outbreaks in birds and or equids had been reported in 116 regions across 11 countries. Belgium reported West Nile animal outbreaks to ADIS for the first time in 2025, Cyprus reported its first animal outbreak, and the Netherlands reported its first equine outbreak to ADIS in October 2025, although the virus had been detected there previously in mosquitoes, birds, and humans. Those developments fit the review’s warning that veterinary systems need to be ready in places that were once considered peripheral to West Nile risk. (efsa.europa.eu)
Industry and scientific commentary has been moving in the same direction. Germany’s Friedrich-Loeffler-Institut said its 2025 data included mapped confirmed infections in birds and horses, underscoring the role of animal surveillance in tracking seasonal activity. Separate recent work on West Nile virus in Germany noted that Europe recorded 494 outbreaks among horses and 447 among birds in 2024, with Germany reporting the majority, and said those figures confirmed the value of effective animal surveillance. WOAH has also signaled that West Nile fever remains important enough to be folded into updated international equine disease standards. (fli.de)
Why it matters: For veterinarians, the practical takeaway is that West Nile virus preparedness increasingly belongs in routine seasonal planning, especially in equine practice and mixed One Health networks. Horses are dead-end hosts, but they can still help reveal viral circulation in an area before a larger human signal emerges. That has implications for vaccination timing, client communication with pet parents and horse caretakers, diagnostic workups for neurologic disease, and coordination with laboratories and public health agencies. It also means practices in regions without a long West Nile history may need to think differently about risk as vector seasons lengthen and the map shifts north. (mdpi.com)
What to watch: The next key signal will be how European countries operationalize these ideas during the 2026 transmission season, including whether equine serosurveillance is expanded in newly affected regions, how quickly animal findings are linked to mosquito and human surveillance, and whether vaccination and reporting practices adapt as West Nile virus keeps pushing into areas that recently saw first-time detections. (mdpi.com)