Clostridia Poisoning

By Imogen Johnson

Horse care

02 August 2010 12:12

Vet and Your Horse expert Gil Riley sheds some light on clostridia poisoning.

Gil says…
Clostridia is a bacteria that lives freely in soil and pasture. There are many varieties of Clostridia so to know exactly which one was responsible for the loss of Julie’s horse would be very difficult. Two of the most commonly encountered Clostridial diseases are Tetanus (also fatal if not caught in time) and Botulism.

In addition, although the jury is still out, we are very confident that it is one of the toxins produced by the Botulism Clostridia that is responsible for the (mostly) fatal condition called Grass sickness.

It is precisely because there are so many types of Clostridia that it is difficult to produce vaccines that we can be confident would be effective as a different vaccine would be needed for each one. As a result, only one vaccination currently exists in the UK for a horse Clostridial disease and that is the Tetanus vaccination. However, in the USA, there are currently trials taking place for a vaccination for Grass sickness - if these are successful it may not be long before this also becomes available in the UK.

The reason that Julie’s horse was the only horse in the field to be affected is probably because Clostridia grows in very specific areas of the field, affecting possibly a tiny area of the pasture. Julie’s horse was simply terribly unlucky in that it grazed this particular patch and as a result ingested the bacteria (or its preformed toxin).

The progress of Clostridial disease is usually very rapid indeed. In fact, in one presentation of Grass sickness (called peracute) the horse is usually found dead when it was totally normal only a few hours before. Fortunately these presentations are very rare. On the other hand, when a horse contracts Tetanus there is usually a more moderate onset when the signs caused by worsening muscle spasm can be identified. In these cases, if concerted broad ranging treatment is rapidly started, horses can make a full recovery.

Unfortunately, it would seem that the rapidity of progress of the condition Julie’s horse suffered means that any attempted treatment would have been hopeless.

Gil Riley