On 28th June 2013 the Animal Health Trust confirmed an outbreak of equine influenza in Hertfordshire. The affected horse was a one month old cob filly that showed clinical signs of depression, pyrexia and pneumonia. A positive diagnosis was made by qPCR on a nasopharyngeal swab. The filly's dam, a 3 year old cob assumed to be non-vaccinated, showed clinical signs of pyrexia and a cough. Six other horses have shown similar clinical signs at the premises in Essex from which the mare and foal originated. 

You can read the AHT's Interim Report here.