Equine Influenza

Equine Influenza Update 23 June 2026

The equine infectious disease surveillance update on the 18 June 2026 highlighted that there have been further outbreaks confirmed for the first time in Fife, Aberdeenshire, Highland, Midlothian and East Yorkshire, bringing the total number of affected counties to 50.

With outbreaks documented across such a large number of UK counties, equine influenza remains a significant disease threat to all sectors of the equine industry. Movement-associated transmission is continuing to introduce infection into previously unaffected regions.

The current outbreak continues to be characterised by extensive geographical spread. Two-thirds of reported outbreaks have involved horses with a recent history of travel, reinforcing the role equine movement and gatherings can play in disseminating infection. With 105 confirmed outbreaks now reported across 50 counties, the outbreak is becoming increasingly dispersed across the country.

A particularly significant development this week has been the confirmation of a clinical case of influenza in a vaccinated Thoroughbred that attended a sale in Ireland the previous week. This is the first reported involvement closely associated with the racing population during the current outbreak.

While vaccination remains highly effective at reducing disease risk and severity, this case serves as a reminder that influenza should remain a differential diagnosis in horses with compatible clinical signs, regardless of vaccination status.

Equine Influenza Update 10 June 2026

UK situation

Since the beginning of April 2026, EIDS has up to 05/06/2025 reported a total of 88 laboratory confirmed EI outbreaks that have been identified across 43 separate UK counties.

Although weekly numbers of reported outbreaks based on sampling date have declined since a surge in activity in mid-late April, the epidemiological picture remains active and somewhat uncertain at the present time (Source EIDS)

Outbreaks per week by sampling date

A similar weekly outbreak count pattern was observed during the 2019 UK EI outbreak before a subsequent and larger resurgence, coinciding with summer movements and events involving unvaccinated horses.

A substantial proportion of outbreaks continue to involve horses that have recently moved premises prior to the onset of clinical signs, reinforcing the role of horse movement in disease dissemination.

Horse owners and their veterinary surgeons should be vigilant for the emergence of signs of respiratory disease (pyrexia (fever), inappetence, coughing and nasal discharge) among animals under their care in non-vaccinated animals, although signs in vaccinated horses should be taken seriously and also be investigated.

Infected horses will spread the virus through coughing and can shed the virus for up to 10 days. Equine Influenza can be highly contagious and – unlike other infectious diseases – can be airborne over reasonable distances as well as be transmitted indirectly, including via people. There are no known consequences for humans associated with exposure to the disease.

Monitor all horses for clinical signs and record their rectal temperatures daily; they should be less than 38.5° C.

Infected horses should be isolated until your vet advises they are no longer infected. All horse movements on and off the yard should be stopped. Booster vaccinate all in-contacts if it's more than six months since their last vaccine, as this has been shown to provide horses with better protection against flu.

Horse owners, yard managers and veterinary surgeons are encouraged to adopt a risk-based approach when moving horses, particularly between premises and events. Vigilance for early clinical signs, maintaining up-to-date vaccination status, and implementing isolation protocols for new arrivals remain essential components of disease control.

Please see the link below for further information for horse owners:

Equine Influenza outbreaks reported in the UK between 29 March and 3 June 2026.

The map reflects all outbreaks reported to EIDS that were sampled between 29 May 2026 and 3 June 2026. Lighter shaded regions are previously reported outbreaks, darker regions are newly reported outbreaks in this update.

When importing horses to the Isle of Man - horses not fully vaccinated must be kept isolated for 14 days following importation.

14 day Isolation Period = this is the quarantine period during which the imported equine must not come into direct (nose-to-nose) contact with any other equine, nor be kept in shared air-space with other equines.

  • The imported equine must not compete on-Island within the isolation period or attend any other event/gathering with other equines
  • The isolation could be indoors (within a stable) or turned out, provided the field boundary does not allow for direct contact with neighbouring equines

Unvaccinated horses

In unvaccinated horses we tend to see certain ‘cardinal’ signs. The virus targets the upper respiratory tract where the cough receptors are positioned so a very harsh dry cough is typical. Often horses will develop a raised temperature which will last around 7-10 days, during this time they may be quiet, off their food and generally sluggish, they may also have a small amount of clear or white nasal discharge and enlarged lymph nodes in their throat.

Vaccinated horses

Horses that have been regularly vaccinated often show no clinical signs, but they may still shed enough virus to infect other horses.

Horses that have been vaccinated but only have partial protection, e.g. because they haven’t been vaccinated frequently enough or because the vaccine type used was not updated, may show varied signs of mild non-specific respiratory disease. This can include mild lethargy, nasal discharge and possibly a cough.