Peer-reviewed veterinary case report
Pimelea trichostachya poisoning (St George disease) in horses.
- Journal:
- Australian veterinary journal
- Year:
- 2007
- Authors:
- Wilson, S-J et al.
- Affiliation:
- Department of Primary Industries and Fisheries · Australia
- Species:
- horse
Plain-English summary
In southern Queensland, a group of horses became sick after grazing on a pasture filled with a toxic plant called Pimelea trichostachya. Out of 35 horses, 10 showed signs of illness, including weight loss, extreme tiredness, runny noses, severe watery diarrhea, and swelling under their jaws and bellies. Blood tests revealed issues like low red blood cell counts and problems with their liver. When the horses were moved to a pasture without this plant, they began to recover. This case is notable because it is the first time this type of poisoning has been documented in horses, although it has been seen in cattle before.
Abstract
A dense population of Pimelea trichostachya plants (Family Thymelaeaceae) in pasture poisoned a horse herd in southern inland Queensland in October-November 2005. Plant density was 2 to 45 g wet weight/m(2) (mean 16 g/m(2)) from 5 to 69 plants/m(2) (mean 38 plants/m(2)) representing 3 to 20% (mean 9%) of the volume of pasture on offer. Ten of 35 mares, fillies and geldings were affected. Clinical signs were loss of body weight, profound lethargy, serous nasal discharge, severe watery diarrhoea and subcutaneous oedema of the intermandibular space, chest and ventral midline. Pathological findings were anaemia, leucocytopenia, hypoproteinaemia, dilatation of the right ventricle of the heart, dilated hepatic portal veins and periportal hepatic sinusoids (peliosis hepatis), alimentary mucosal hyperaemia and oedema of mesenteric lymph nodes. Cattle grazing the same pasture were affected by Pimelea poisoning simultaneously. Removal of the horses to Pimelea-free pasture initiated recovery. The one other incident of this syndrome, previously only recognised in cattle in Australia, occurred in horses, in South Australia in 2002, with access to a dense Pimelea simplex population.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/17470070/