Vermeersiekte Caused by Geigeria Burkei Harv. Subsp. Burkei Var
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Research Communication — Navorsingsberig Vermeersiekte caused by Geigeria burkei Harv. subsp. burkei var. hirtella Merxm. in the Northern Province of South Africa C J Bothaa, T A Gousb, Mary-Louise Penrithc, T W Naudéa,d, Leonie Labuschagned and Elizabeth Retiefe myofibres of the skeletal system, ABSTRACT diaphragm and oesophagus, as well as The 1st field outbreak of vermeersiekte induced by Geigeria burkei Harv. subsp. burkei var. foci of myocardial degeneration and hirtella Merxm. is reported. It is also the first recorded outbreak of this disease in the arid necrosis. sweet bushveld of the Northern Province of South Africa. The toxicosis was experimentally Vermeerbos (the common name for reproduced in a sheep following daily intraruminal administration of 2.5–5.0 g/kg dried, plants of the genus Geigeria) is reported to milled plant material for 18 consecutive days. Neither the sheep in the field outbreak nor be moderately nutritious15. Grosskopf6 the ewe in the experiment exhibited any signs of regurgitation of rumen contents (vermeer- stated that vermeerbos, in limited quanti- siekte). All developed only the stiff or paretic/paralytic forms of the disease. Serum activities of CK and GGT were slightly raised in clinically affected sheep (n = 11) during the field ties, appears to be an excellent feed for outbreak, and serum activities of AST, GLDH, GGT, LDH and CK increased in the ewe sheep, as it retains its protein concentra- dosed with the plant material. Analysis of dried, milled Geigeria plant material confirms that tion during winter, whereas that of this species is moderately nutritious. grasses rapidly decreases after the growing season. Key words: Geigeria burkei, paralysis, paresis, sheep, stiffness, vermeersiekte. Botha C J, Gous T A, Penrith M-L, Naudé T W, Labuschagne L, Retief E Vermeersiekte FIELD OUTBREAK caused by Geigeria burkei Harv. subsp. burkei var. hirtella Merxm. in the Northern During the end of winter (August 1996) Province of South Africa. Journal of the South African Veterinary Association (1997) 68(3): approximately 50 sheep in a flock of 200 97–101 (En.). Department of Pharmacology and Toxicology, Faculty of Veterinary Science, Dorpers on the farm Drielingbosch University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa. (23° 17′ S, 29° 41′ E), near Bandolierkop in the Soutpansberg district of the Northern Province, exhibited listlessness, stiffness INTRODUCTION tion losses6. G. aspera is associated with in the hindquarters, lameness and lagging Vermeersiekte following ingestion of more localised poisoning on the highveld behind the rest of the flock. A decline in different Geigeria species is a major intoxi- of Mpumalanga and the northern Free their condition was also noticed by cation of small stock in South Africa. State10,11. Under experimental conditions the farmer and some animals became Geigeria ornativa is the most important G. burkei subsp. burkei var. zeyheri induced paretic/paralytic. Some sheep were cause of vermeersiekte in the dry vermeersiekte, although there is no unable to rise and remained in sternal or Griqualand West area of the Northern confirmed report of any natural field lateral recumbency. When sheep were Cape11,15. Vahrmeijer13 reported that during outbreak10. Various α,β-unsaturated-8- assisted to stand the limbs trembled and a 1929–1930 as many as a million sheep died sesquiterpene lactones have been isolated staggering gait was observed. Two weeks in Griqualand West. Kellerman et al.11 from different Geigeria species and are before the investigation the farmer insti- calculated the economic impact of plant implicated as the toxic principles2,10,11. tuted supplementary feeding consisting poisonings and estimated that in 1996 The toxicity of the 3 species mentioned of a salt and flowers-of-sulphur lick, maize monetary terms the annual loss due varies. It has been estimated that G. burkei stover and poultry litter. The farmer to vermeersiekte mortalities exceeds subsp. burkei var. zeyheri is 3 times and G. incriminated a small, green, herbaceous 6 million Rand. The economic loss could aspera 10 times more toxic than G. orna- bush as the cause of the paretic condition. be considerably higher, as vermeersiekte tiva6,10. Sheep in feeding experiments with On inspection of the camp and observa- is known to be an erosive disease that G. ornativa hay ingested the plant for tion of the animals it was noticed that the causes various production and reproduc- prolonged periods and clinical signs were sheep eagerly ingested the incriminated noticed only after 3 weeks6. Clinically, 4 herb (Fig. 1), which was the only greenery forms of the disease are recognised, available at the time. The plant was recog- namely regurgitation (‘vomition’), stiff- nised as a Geigeria species and was aDepartment of Pharmacology and Toxicology, Faculty of ness, bloat and paresis/paralysis10. Regur- collected and submitted for identification. Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa. gitation is not a common finding, and The presence of Helichrysum argyro- sheep usually exhibit stiffness, particu- sphaerum in the camp was also noted. The bVeterinary Laboratory, Private Bag X2408, Louis Trichardt, 0920 South Africa. larly of the hindquarters, in the early farmer reported that the flock was moved 10,15 cPathology Section, Onderstepoort Veterinary Institute, stages of the toxicosis . Macroscopical 8 months previously to another farm, Private Bag X05, Onderstepoort, 0110 South Africa. lesions are usually absent, but a mega- Potgietersrand (23° 15′ S, 29° 43′ E), where dToxicology Section, Onderstepoort Veterinary Institute, oesophagus may be encountered in some the veld was trampled and the grazing Private Bag X05, Onderstepoort, 0110 South Africa. cases and sheep may die from a foreign sparse, although abundant green Geigeria eNational Botanical Institute, Private Bag X101, Pretoria, body pneumonia if rumen fluid is aspi- was present. The sheep grazed on this 0001 South Africa. rated10,11. Van der Lugt and Van Heerden14 particular farm for 4 months before being Received: April 1997. Accepted: July 1997. reported hypertrophy and vacuolation of returned to the present property. Blood 0038-2809 Jl S.Afr.vet.Ass. (1997) 68(3): 97–101 97 Laboratory trial A 1-year-old Dorper ewe, with a cannula fitted into the rumen, was housed in a concrete pen at the Laboratory Animal Facility of the Toxicology Section at the Onderstepoort Veterinary Institute (OVI). She had free access to water and was fed oats hay and a maize meal-based pelleted concentrate. During a 2 week adaptation period and throughout the experimental period, regular clinical examinations and ECG recordings (Ectromed) were performed. Before and during the trial, blood samples were collected twice a week from the jugular vein and submitted for determination of serum activities of glutamate dehydro- genase (GLDH), AST, GGT, CK and LDH. Dried, milled plant material collected from the field outbreak was administered via the rumen cannula on consecutive Fig. 1: Sheep eagerly ingesting Geigeria burkei Harv. subsp. burkei var. hirtella Merxm. on days (n = 18) according to the dosing a farm in the Northern Province. regimen presented in Table 1. Dosing ceased once clinical signs were observed. The ewe was weighed weekly and the intraruminal dose adjusted accordingly. A sample of the dried, milled plant material was also submitted for feed analysis. RESULTS Plant identification The incriminated plant was identified as Geigeria burkei Harv. subsp. burkei var. hirtella Merxm.7,12 (Fig. 2) by the National Botanical Institute, Pretoria. Family Asteraceae Common name Most probably also vermeersiekte- bossie. Fig. 2: Geigeria burkei Harv. subsp. burkei var. hirtella Merxm. Description7,12 A several-stemmed perennial herb with a woody rootstock, forming a round bush, samples from 21 sheep, ranging from carboxylic ionophore antibiotic poison- semi-woody, 0.2–0.3 m tall. Stems densely severely affected (n = 11) to apparently ing, samples of the poultry litter (n = 2) covered with crinkled, whitish, multicel- healthy animals (n = 10), were collected were also submitted for thin layer chro- lular hairs, branching in upper part with from the jugular vein. The blood was matography (TLC) and calorimetric more than one branch from the apex of allowed to clot, the serum collected and analysis5. A necropsy was performed on a main stem, brownish. Leaves alternate, submitted for determination of aspartate sheep that was euthanased and samples sessile, linear, 20–50 × 0.5–1.5 mm, margin transaminase (AST), gamma-glutamyl of brain, lung, liver, spleen, kidney, heart strongly revolute, densely covered with transferase (GGT), lactate dehydrogenase and skeletal muscle including oesopha- glands and white, crinkled multicellular (LDH) and creatine kinase (CK) activities. gus were preserved in 10 % buffered hairs. Flower heads in axils of branches These serum enzyme activities were formalin and submitted for histopatho- with leaves involucrate. Involucre globose determined by an automated chemical logical examination. The tissues were to campanulate, 10–20 × 8–10 mm, 4- analyser (Technicon RA-1000 Analyser, routinely processed and stained with seriate, outer bracts long, leaf-like, appen- Technicon Instruments Corporation) haematoxylin-eosin (HE). A provisional diculate, inner bracts brownish, using the manufacturer’s methods and diagnosis of vermeersiekte was made and acuminate-lanceolate, margin in upper reagents,