ABOUT THE EGS VACCINE TRIAL
Background to the EGS vaccine trial
Almost all cases of EGS occur in horses with access to grazing, and we think they are exposed to some form of noxious agent present in the soil and ingested as a contaminant of grass. There is growing scientific evidence to suggest that EGS may be caused by the bacterium Clostridium botulinum (C. botulinum) type C, which is found commonly within soil and is capable of producing a range of toxins, including potent neurotoxins (toxins that damage the nervous system), to which horses are particularly sensitive. The current theory is that EGS is a toxico-infectious form of botulism caused by C. botulinum type C, with the disease occurring when a combination of risk factors triggers the production of neurotoxin locally in the horse’s intestinal tract.
Several research studies of EGS have demonstrated a protective effect of natural immunity to C. botulinum type C. In addition, other clostridial diseases, such as tetanus and botulism, are successfully prevented by vaccination, suggesting that it should theoretically be possible to prevent EGS by vaccination. With Britain having the highest incidence of EGS worldwide, this nationwide field vaccine trial has been designed to evaluate whether vaccination against C. botulinum type C can help to prevent EGS.
What is involved in the EGS vaccine trial
In March 2014, the Animal Health Trust launched the EGS vaccine trial, in collaboration with the Universities of Edinburgh, Liverpool and Surrey. The EGS vaccine trial has been authorised under an Animal Test Certificate issued by the Veterinary Medicines Directorate. This field trial will enrol over 1,000 horses and ponies, from British premises affected by EGS within the preceding three years, and then follow them over a period of two years.
Based on the protocols used in the highest standard human clinical trials, once horses and ponies are enrolled in the EGS vaccine trial, they are selected at random, using computer-generated random numbers, to join either the vaccine group (which will receive a full course of the C. botulinum type C vaccine) or a placebo-treated group (which will receive a full course of inactive placebo injections). The primary course will involve a total of 3 injections, given at 3 week intervals, followed by an annual booster injection.
Full details of the EGS vaccine trial can be found by downloading the owner information pack . If you are interested in taking part in the EGS vaccine trial, we would urge you to read through the owner information pack thoroughly, and to discuss any questions you may have with the EGS vaccine trial study staff or your veterinary surgeon before deciding whether or not to participate.
Enrolling insured horses or ponies
If your horse/pony is insured, you must inform your insurance company prior to enrolling them in the EGS vaccine trial. Please download this form, complete your details and sent it to your insurance company.
If you would like to enrol in the EGS field vaccine trial, there are several criteria for including horses or ponies in the trial that you need to consider:
To be eligible for enrolment in the EGS vaccine trial, horses and ponies must:
- have a valid passport that complies with the Horse Passports Regulations 2009. Part II of Section IX of the passport must state the animal is not intended for human consumption and must be signed by the owner and officially countersigned by an authorised individual. For more information, or to check if your horse/pony’s passport is valid, please consult the Department for Environment Food & Rural Affairs website http://archive.defra.gov.uk/foodfarm/farmanimal/movements/horses/horses_qa.htm or the Gov.UK website https://www.gov.uk/horse-passport
- be in good general health
- be 6 months of age or older
- not be in foal or have a foal at foot
- not be on any form of steroid treatment
- not currently have EGS or have had EGS in the past
If there have been no cases of EGS on the premises where you keep your horse/pony within the last 3 years, unfortunately you would not be eligible for participation in this trial. To allow us to evaluate the effect of vaccination on the risk of EGS, we need to enrol a minimum of 10% of all horses and ponies living on each premises – for example, if there are 20 horses and ponies on your premises, we would require that a minimum of 2 horses and ponies are enrolled in the trial.
Season as a risk factor
The high risk season for EGS has now come to an end. However, cases can occur throughout the year and there is generally a small increase in incidence during the autumn months. To find out more about minimising the risk of this debilitating disease please click here
Horses and ponies from 39 different counties in
Scotland and England are currently enrolled in the
EGS vaccine trial.
EGS Vaccine Trial Facts and Figures: The most popular names amongst horses and ponies taking part in
the trial are ‘Jack’ and ‘Misty’, with close runners up
being 'Archie', 'Barney', 'Blue', ‘George’ and ‘Lady’.
The oldest horse participating in the trial is 29 years
while the youngest is 6 months old.
The average age of the horses and ponies enrolled on the trial is 8 years old.