Prof Ann Cullinane

EQUINE influenza has recently been confirmed by the Irish Equine Centre in counties Meath, Tipperary, Kildare and Clare.

The majority of affected horses are unvaccinated non-thoroughbreds but spillover into the thoroughbred population is inevitable. Some vaccinated horses, including a four-year-old racehorse have exhibited clinical signs and tested positive.

The three most common signs of equine influenza are fever, nasal discharge and persistent coughing. The virus has a short incubation period in naïve horses and disease spread can be rapid. In horses that are partially immune as a result of vaccination or previous exposure, clinical signs may be mild and the disease spreads more slowly. In vaccinated racehorses clinical signs may be limited to a decrease in appetite and a loss of performance. Owners should contact their veterinary surgeon if they have any concerns in relation to their horses.

As an OIE (World Organisation for Animal Health) reference laboratory for equine influenza, the Centre offers free diagnostic testing for influenza. It also provides a free blood testing service to determine if a horse is protected against equine influenza or requires booster vaccination. If equine influenza is confirmed there is a subvention towards the costs of further sample collection by the veterinary surgeon to investigate the extent of the outbreak.

Virus is readily transmitted at sales, hunts and shows and all horses and ponies should be vaccinated against influenza. The vaccines are effective but the companies are slow to update their products in line with the recommendations of the OIE.

The strain circulating in Ireland at present is similar to those circulating in previous years, both here and in the UK. It is not contained in any of the vaccines at present but they should all provide a reasonable level of cross protection.

It is anticipated that an updated vaccine will be available here in the new year.