Mallorca on West Nile alert after four horses test positive

Health services across Mallorca and the Balearics are stepping up checks after four horses in Maó, Menorca tested positive for West Nile fever. On Monday, 21 September, the Balearic Public Health Agency alerted both public and private health providers to spot possible human cases early. No locally acquired human case has been reported in the Balearics.

The virus has also not appeared in routine tests on blood donations and other blood components carried out by the Blood and Tissue Bank Foundation since summer 2024. Those checks also look for other mosquito-borne viruses, including dengue and Zika. West Nile fever must be reported to the authorities.

Monitoring expands across the islands

These are the first confirmed West Nile fever cases in the Balearics this year. Menorca recorded its first case in an equine animal at the end of August 2025.

That finding led the Directorate General of Public Health to begin monitoring for the virus in its carriers on Menorca. The programme has continued this year and now covers the other islands; until these horse cases, none of the samples tested had found the virus.

Advice focuses on mosquito bites

The health agency is working with other authorities on further action to strengthen surveillance and prevent human cases. It has urged people, particularly those in risk groups, to avoid mosquito bites.

The advice includes using authorised repellent and wearing long sleeves. Small collections of water should be removed because they can become breeding spots. Mosquito nets and repellent can also help keep mosquitoes out of homes.

Topics: Nature & wildlife · Health · Culture

Source: Europa Press / Mallorca.com