Grass Sickness Remains Research Priority

The death of Dubai Millennium from grass sickness has again highlighted the devastating effects of the disease, and brought to prominence research tied to finding causes and a cure.

In Great Britain, research is being carried out at Edinburgh and Liverpool Universities, which both have well-known veterinary schools and facilities. The Equine Grass Sickness Fund and Animal Health Trust also are involved.

The Edinburgh research, which receives funding from the Levy Board, largely centers on a possible connection between grass sickness and the bacteria clostridium botulinum. Research being carried out at Liverpool is more general and involves the possible causes of fungi and the weather.

The Equine Grass Sickness Fund, a charity involved with helping horse owners, is working in conjunction with other parties. One trial is investigating whether there is a possible link between grass sickness and cyanide in white clover.

In addition, the fund is carrying out a long-term epidemiological study in conjunction with the Animal Health Trust in Newmarket and the Royal School of Veterinary Studies in Edinburgh to examine a range of possible factors such as age, season, weather, and type of pasture.

One problem is there is no centralized system of logging cases, because there is no obligation for owners to report the death of a horse from grass sickness -- it is a non-notifiable disease under Ministry of Agriculture regulations.

In addition to Dubai Millennium, other well-known horses to have died from the disease include Moorestyle, the champion European sprinter of 1980 and 1981; Branston Abbey, a mare who had won 24 of her 99 races; and 1995 Royal Ascot winner Diaghilef in 1999. Mister Baileys, the 1994 Two Thousand Guineas (Eng-I) winner, managed to recover from the disease soon after he started his stallion career.

Grass sickness was first identified in 1907 among a group of agricultural horses near Dundee, Scotland, where most cases of grass sickness occur. In particular, the east coast of Scotland seems particularly affected. Overall, most cases of grass sickness throughout Britain are located in part of the country that includes the Newmarket area.

Some theories claim the disease seems most prevalent when the temperature is cool. Most cases of grass sickness tend to occur between April and July, and peak in May. A second peak can sometimes occur in the autumn.