First West Nile Virus Case in Horse Confirmed in Belgium
Belgium has confirmed its first case of West Nile virus in a horse, prompting health authorities and veterinarians to urge heightened vigilance. The animal, from the Brussels periphery, was euthanized on August 4 after developing severe neurological symptoms, according to RTBF.
The case was identified not through a formal surveillance program but by a veterinarian’s clinical suspicion, who recognized the symptoms and requested serological analysis that confirmed the infection. Dr. Pierre Paindaveine, president of the equine section of the Union Professionnelle Vétérinaire (UPV), emphasized the significance of this discovery: “This case was not found by a surveillance system, but by a veterinarian who thought of the right hypothesis when faced with a sick horse.”
A Sentinel for Human Health
West Nile virus circulates naturally between Culex mosquitoes and birds, and can occasionally be transmitted to other species, including horses and humans. Neither infected horses nor humans can transmit the virus to others, posing no danger to those around them.
However, the equine case carries particular significance. As L’Avenir reported, the UPV stressed that “when a virus circulates in horses—like West Nile virus—they can become true health sentinels, alerting to virus circulation in a region, sometimes even before the appearance of human cases.”
“The horse has an indicator value,” Dr. Paindaveine explained. “It is bitten in large numbers, it develops visible neurological forms more frequently than humans, and it is followed by professionals capable of recognizing them. In Europe, the appearance of equine cases regularly precedes that of human cases in the same territory.”
His warning to the medical community was direct: “The horse is the indicator that the next step is humans. Doctors, open your eyes!” as reported by La Libre.
Virus Establishing Itself in Belgium
The detection of the virus in Belgian birds dates back to August 2025, when the first wild bird cases were identified in Flanders through a surveillance study. Three crows tested positive that year, and the virus was detected in birds again in May and July 2026. The first equine case confirms that the virus is establishing itself in the country.
Belgium had previously only recorded imported human cases, first diagnosed in 2012 in three travelers returning from Greece, the Democratic Republic of Congo, and Sudan. The progression of the virus northward across Europe has been linked to climate change, which affects mosquito reproduction and virus incubation, as noted in an RTBF background article.
European Context and Rising Concerns
The Belgian case comes amid a broader European surge in West Nile virus activity. According to Euronews, Greece reported 65 cases by August 5, with six deaths, all in patients over 65 with severe neurological involvement. Italy leads with 94 cases, followed by North Macedonia and Spain with seven each, Romania with five, France with two, and Germany with one.
The World Health Organization warned on July 24 that the virus is spreading and called for enhanced mosquito surveillance and public information. Dr. Hans Henri P. Kluge, WHO Regional Director for Europe, stated: “The West Nile virus is not a new threat, but the conditions of its spread are evolving rapidly.”
In 2025, 14 European countries reported 1,112 human cases and 97 deaths, along with 186 equine outbreaks and 359 bird outbreaks, according to ECDC surveillance data.
Recommendations and Prevention
The UPV reassures that no emergency measures are needed for horse owners, but standard mosquito precautions apply: eliminating stagnant water around stables, using approved insecticides, and consulting a veterinarian for any weakness or incoordination. A vaccine exists for horses, though its use should be discussed with the treating veterinarian, considering the several weeks needed for immunity to develop.
In humans, about 80% of infections are asymptomatic, and most others present flu-like symptoms. Neurological forms occur in about 1% of cases, mainly in elderly or immunocompromised people. No vaccine exists for humans—the only protection is avoiding mosquito bites through protective clothing, repellents, mosquito nets, and eliminating stagnant water.
Dr. Paindaveine stressed the importance of veterinary vigilance: “The clinical picture is common to several diseases. It’s really important that veterinarians are attentive to look for it. When there’s a suspicion, you can report it to the AFSCA and then a laboratory test is performed based on a blood sample.”
What to Watch For
As the virus continues its northward expansion across Europe, Belgian health authorities and the medical community will be monitoring for potential human cases. The equine case serves as a critical early warning signal—one that veterinarians and doctors alike are being urged to heed.