It´s a highly infectious viral respiratory disease characterised by fever and dry coughing, mostly affecting non-vaccinated horses.
It´s transmitted from horse to horse in close proximity by coughing and inhaling aerosolised live virus and also from horses to people to horses via hands, clothes, grooming equipment or tack contaminated with infectious material.
Overcrowding of horses, poor stable biosecurity, poor hygiene, feeding and water supply conditions and the transport of horses are all predisposing risk factors for spread of infection.
Clinical signs in horses are highly variable in severity, young horses are the most susceptible. A high fever of up to 41°C, depression, nasal discharge, conjunctivitis, swollen legs and a non-productive dry cough, sometimes with swollen glands under the throat are typical of acute infection.
Severely affected horses may develop complications like pneumonia and less commonly vasculitis, myositis and myocarditis. These conditions can be serious, requiring intensive care and treatment and may cause prolonged debilitation.
There is now a human influenza A virus antigen detection rapid test which is available at a number of equine veterinary laboratories, which will give a reliable same day result.
This article is based in scientific veterinary literature.