Evidence map›Paper›PMID 38301732›Full record

ArticleEquine veterinary journal2025

Equine grass sickness is associated with major abnormalities in the ultrastructure of skeletal neuromuscular junctions.

Bruce C McGorum, Tracey Davey, Miranda C M Dosi, John A Keen, Linda R Morrison, R Scott Pirie, Darren J Shaw, John B Harris

Open access · hybridAbstract read
In one paragraph

Article in Equine veterinary journal, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 5 papers.

0numbers the graph read from it
0cells of the map it votes in
5citing papers in PubMed
2.2field-weighted citation impact, top 12% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

5 citing papers in PubMed, 6 citations in OpenAlex.

  1. Article
  2. Equine botulism.Equine veterinary journal · 2026
    Review
  3. Review
  4. Article
  5. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors at 2 institutions in 1 country.

Bruce C McGorumRoyal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Roslin, UK.ORCID https://orcid.org/0000-0002-6977-6101
Tracey DaveyElectron Microscopy Research Services, Newcastle University, Faculty of Medical Sciences, Newcastle upon Tyne, UK.
Miranda C M DosiRoyal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Roslin, UK.ORCID https://orcid.org/0000-0002-1094-1184
John A KeenRoyal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Roslin, UK.ORCID https://orcid.org/0000-0002-7862-5321
Linda R MorrisonRoyal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Roslin, UK.ORCID https://orcid.org/0000-0003-0495-4592
R Scott PirieRoyal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Roslin, UK.ORCID https://orcid.org/0000-0003-4299-4077
Darren J ShawRoyal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Roslin, UK.ORCID https://orcid.org/0000-0003-2016-1541
John B HarrisMedical Toxicology Centre and Institute of Neuroscience, Newcastle University, Faculty of Medical Sciences, Newcastle upon Tyne, UK.
Roslin Institute · GBNewcastle University · GB

Funding

Royal College of Veterinary Surgeons Trust Blue Sky Research FundThe Equine Grass Sickness Fund
6 · The paper itself

Abstract

backgroundEquine grass sickness (EGS) is a frequently fatal multisystem neuropathy of equids. The aetiology is unknown; proposed causes include toxicoinfection with Clostridium botulinum and a mycotoxicosis. The effect of EGS on the organisation and structural integrity of the skeletal neuromuscular junction (NMJ), the target of botulinum neurotoxins (BoNTs), is unknown.

objectivesTo compare the organisation and structural integrity of skeletal NMJs from EGS horses, control horses and one horse with a presumptive diagnosis of botulism. STUDY

designBlinded, retrospective case control.

methodsNMJs in samples of diaphragm or intercostal muscle from six EGS horses, three control horses and one equine botulism case were compared using electron microscopy, morphometry and confocal light microscopy.

resultsA significantly higher percentage of EGS NMJs had abnormal morphology (EGS 72.2%, 95% CI 55.6-84.4; Controls 6.9%, 1.7-23.8; OR 35.1, 8.47-244.8; p < 0.001). EGS NMJs had a significantly lower mean volume fraction occupied by synaptic vesicles (SVs) (EGS 18.7%, 12.6-28.0; Controls 36.3%, 20.8-63.4; p = 0.024). EGS NMJs had evidence of accelerated SV exocytosis and SV depletion, accumulation of neurofilament-like material in terminal boutons and/or bouton degeneration. NMJs from the botulism horse had dense packing of SVs towards the presynaptic membrane active zone, consistent with BoNT intoxication, but had absence of the abnormalities identified in EGS NMJs. MAIN LIMITATIONS: Group sizes were limited by difficulties obtaining suitably processed samples. Ages of control and EGS horses differed. Botulism was diagnosed based on clinical and post mortem findings.

conclusionsEGS is associated with major changes in skeletal NMJ ultrastructure that are inconsistent with the effects of BoNTs. SV depletion may reflect increased exocytosis coupled with reduced repopulation of SVs via anterograde axonal transport and endocytosis, consistent with the action of an excitatory presynaptic toxin and/or neurotransmitter reuptake inhibitor. Skeletal NMJs represent a previously unrecognised target for the toxin that causes EGS.

Indexed as

BotulismHorse DiseasesNeuromuscular JunctionAnimalsCase-Control StudiesFemaleHorsesMaleMuscle, SkeletalRetrospective Studiesbotulismequine grass sicknesshorsemultisystem neuropathyneuromuscular junction

Identifiers

PMID38301732
PMCPMC11616959
OpenAlexW4392787360

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC-ND
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.