Datura contamination of hay as the suspected cause of an extensive outbreak of impaction colic in horses : clinical communication

T.W Naudé,R.J Smith,C.J Botha,R Gerber

doi:10.4102/jsava.v76i2.407

Abstract

Datura poisoning of horses is extensively reviewed. An outbreak of intractable impaction colic affecting 18 of 83 horses was stopped by withdrawing dried tef hay contaminated with young Datura plants. The dried, botanically identified Datura stramonium and D. ferox contained respectively 0.15% mass/mass (m/m) hyoscyamine as well as 0.16% m/m hyoscine (scopolamine) and only hyoscine at a concentration of 0.11% m/m. Immature, unidentifiable plants resembling D. stramonium, contained 0.14% m/m and 0.12% m/m of the 2 respective tropane alkaloids. The outbreak was characterised by protracted and repeated colic attacks due to impaction of the large colon and/or caecum without any other anti-muscarinic signs. Comparative analyses of single specimens of dried seed of the 2 species collected from both fertilised and waste areas revealed that young South African Datura spp. had levels of tropane alkaloids comparable to those in the well-known toxic seed and were, consequently, equally toxic. The inherent danger of tef hay being contaminated with Datura is emphasised. To our knowledge this is the 1st field case of poisoning in horses ascribed to the vegetative parts of Datura spp.

Highlights

Datura stramonium L. and D. ferox L. are the 2 cosmopolitan weed species of this genus of the Solanaceae commonly encountered in South Africa
In the 1st case[16, 1] horse died from acute gastric dilatation and rupture whereas the 2nd had to be euthanased due to unresponsive paralytic ileus. As this incident had occurred in South Africa, it is assumed that the seed involved was probably a mixture of that of D. stramonium and D. ferox
The attending veterinarian referred a number of affected animals to the Equine Clinic of the Department of Companion Animal Medicine at the Faculty of Veterinary Science, Onderstepoort, where a tentative diagnosis of atropine intoxication was made as some Datura plants were found in the hay submitted with the animals

Summary

INTRODUCTION

Datura stramonium L. (common thorn apple, gewone stinkblaar, Fig. 1) and D. ferox L. (large thorn apple, grootstinkblaar, Fig. 2) are the 2 cosmopolitan weed species of this genus of the Solanaceae commonly encountered in South Africa. In the 1st case[16, 1] horse died from acute gastric dilatation and rupture whereas the 2nd had to be euthanased due to unresponsive paralytic ileus As this incident had occurred in South Africa, it is assumed that the seed involved was probably a mixture of that of D. stramonium and D. ferox. Clinical signs consisting of severe gastrointestinal atonia, tachycardia, sweating and colic, were seen at only the highest dose of 0.5 g/kg, equivalent to 0.275 mg scopolamine and 0.185 mg atropine/kg (in addition to the other unquantified related tropane alkaloids in the plant). The attending veterinarian referred a number of affected animals to the Equine Clinic of the Department of Companion Animal Medicine at the Faculty of Veterinary Science, Onderstepoort, where a tentative diagnosis of atropine intoxication was made as some Datura plants were found in the hay submitted with the animals. Five days later it had to be euthanased due to recurrence of the same problem

ANALYTICAL RESULTS

DISCUSSION

Adams H R 1995 Cholinergic pharmacology