The “Syndrome”: Not Just for Fell Ponies Anymore

A rare and lethal “syndrome” has been observed in Fell pony foals since at least 1993, when it was first reported by Paul May, a veterinarian in Cumbria. Worldwide approximately 10-12 cases are reported each year out of 300-350 foals that are born, and the disease has been seen in all major bloodlines. To date in North America, less than five confirmed cases (from several different lines) have occurred over the last 15 years, so the disease is indeed very rare. Affected foals appear healthy until about 4-6 weeks, when they begin to lose condition and eventually die or are euthanized before weaning. The cause of death is usually severe anemia as well as multiple infections. The underlying cause of disease is unknown, but is believed to be due to a genetic fault. Foals that remain healthy at 2 months of age are very unlikely to develop the disease, while those that reach 3 months of age are no longer considered at risk. The “Fell Foal Syndrome” has always been somewhat of an ambiguous term for this disease. What it has referred to is a syndrome, or a group of characteristic signs and symptoms, seen exclusively in sick, newborn Fell pony foals. Unfortunately, in 2008, the latter restriction is no longer accurate, as the first confirmed case of the “Syndrome” occurred in the Dales pony breed in the UK. By Mary Jean Gould-Earley, MD