Introduction to Equine Grass Sickness

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About the course

This online veterinary nursing lecture discusses Equine Grass Sickness (EGS), which is is both a devastating and fascinating disease.  The cause of the disease remains elusive despite many years of research.  Other species of animals can suffer from a similar form of the disease.  Both central and peripheral nervous systems are affected producing clinical signs that vary in severity.  There are 3 disease severities: acute, sub-acute and chronic, the first two being fatal.  A definitive diagnosis remains challenging due in part to not having a non-invasive diagnostic test.  Confirmation of diagnosis at post-mortem is important to enable advice to be given to owners of horses kept at the same premises as the affected case.  Reporting cases to both the Animal Health Trust Surveillance Scheme and Equine Grass Sickness fund is vital to establish accurate numbers of horses affected so that this information can be used for future vaccine trials.


Learning Outcomes

  • A general background understanding of equine grass sickness (EGS) disease development and distribution.
  • The ability to recognize clinical signs of acute, sub-acute and chronic EGS.
  • Understanding of the difficulties with regard to clinical diagnosis.
  • Understanding of confirmation of diagnosis at both gross post-mortem and histological interpretation.


Bryony Waggett HND BSC MSC

Peer Review:

Dr. Scott Pirie BVM&S PHD CertEP CertEM(Int Med) DipECEIM MRCVS

Senior Lecturer in Equine Medicine, University of Edinburgh Large Animal Hospital

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