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Quick answer: in 2026 West Nile fever reached horses in places where it had never been detected before, such as Gran Canaria, and returned to Menorca. By early September Spain had recorded 21 animal outbreaks this season. The virus is spread by Culex mosquitoes; horses do not infect other animals or people. The best protection combines vaccination (ask your vet) with mosquito control around the yard.
First cases in the Canary Islands and a new outbreak in Menorca
On 20 August 2026 the Central Veterinary Laboratory in Algete confirmed West Nile virus in three horses at an equestrian centre in the south of Gran Canaria, the first detection in the Canary Islands. The alert came from a vet who had seen neurological signs. On 1 September a fourth case was confirmed at a yard in Santa Brígida with 54 horses, with no symptoms in the other animals. No human cases have been diagnosed in the islands.
In the Balearics, the first outbreak of the season was confirmed on 11 September 2026 in Maó (Menorca), on a holding with 30 equines. According to the figures published at the time, the virus circulated in 2026 in Andalusia, Catalonia, Extremadura, Castilla-La Mancha, the Canary Islands and the Balearics.
Symptoms in horses and what to do
The Spanish Ministry of Agriculture's guide to West Nile fever lists these warning signs: changes in behaviour, hypersensitivity, muscle twitching, falling or circling, seizures or being unable to stand, with or without fever. It is a serious disease: around a third of horses showing clinical signs die.
If you suspect anything, call your vet. Reporting to the official veterinary services in your region is compulsory and, as a general rule, must be done within 24 hours. Keep the horse's vaccination record and recent movements to hand.
Vaccination and mosquito control: why autumn still matters
There is an inactivated vaccine authorised in the EU for equines. Your vet will advise on the right schedule for your horse's age and the situation in your area, and it should be recorded in the horse's documents. Vaccination is particularly recommended for high-value animals or when the epidemiological situation is serious.
Mosquito control is the other key piece, and autumn counts: female Culex mosquitoes overwinter in stables and storerooms, so the Ministry advises at least one winter treatment of these spaces with authorised products.
- Get rid of standing water: empty or cover buckets, drums and tyres, and fix overflowing troughs or leaks that leave puddles.
- Protect at peak times: bring horses in at dusk and overnight, when mosquitoes bite most.
- Screens in the stable: fit them on doors and windows without reducing ventilation.
- Products on the horse: never apply insecticides on your own initiative; always check with your vet.
Fly sheets and masks reduce insect nuisance and bites, but they do not replace vaccination or mosquito control in the surroundings.
See more horse rugs and sheets, horse boots and protection and feeders and drinkers for horses.
Frequently asked questions
Can my horse pass West Nile virus to other horses or to me?
No. Equines and people are dead-end hosts: they do not transmit the infection or act as a reservoir. The virus circulates between birds and mosquitoes.
Do healthy horses on an affected holding have to be culled?
No. According to the Spanish Ministry of Agriculture, there is no need to cull healthy animals or impose general movement restrictions on equines, unless the competent authority decides otherwise case by case.
When should horses be vaccinated against West Nile fever?
It depends on the horse's age, history and the situation in your area. Ask your vet to recommend the best schedule before the next mosquito season.
Keep reading
- Horse care equipment: the essential list for the yard
- Cleaning and disinfecting animal facilities step by step
- Biosecurity on farms and animal premises
Sources
- RTVC: West Nile virus confirmed for the first time in the Canary Islands in three horses (20 August 2026)
- RTVC: fourth case in a horse in the Canary Islands (1 September 2026)
- Diario Veterinario: first 2026 outbreak in equines in the Balearics (15 September 2026)
- Spanish Ministry of Agriculture: guide to West Nile fever