Biomedical subjects
Publications and source records attributed to F S Malan.
A herd of Bonsmara bulls in the Eastern Transvaal was found to be suffering from mange. Scrapings were made and the mites that were collected was identified as Psorergates bos.
A new species of nematode, Cylicodontophorus reineckei, was collected from Burchell's zebra, Equus burchelli antiquorum H. Smith, 1841, in both the Etosha National and Kruger National Parks and from mountain zebra, Equus zebra hartmannae Matschie, 1898, in the Namib Naukluft Park in South West Africa/Namibia. These nematodes have an external leaf-crown with longer elements than those of the internal leaf-crown and a well-developed dorsal gutter. The very well-developed oesophageal funnel is both wider and deeper than the buccal capsule.
Fenbendazole, dosed to artificially infested cattle at 5 mg/kg live mass, was more than 60% effective in more than 60% of the treated animals against 1-7 day-old Dictyocaulus viviparus larvae reducing the worm load by 87%. It was more than 80% effective in more than 80% of the treated animals against 8-21 day-old worms and 21-34 day-old worms and reduced the worm burdens by 99% in both cases.
Fenbendazole, dosed to experimentally infested sheep at 5 mg/kg live mass, against immature Dictyocaulus filaria, was more than 80% effective in more than 80% of the animals.
The external ultrastructure of the anterior and posterior extremities of the nematodes, Strongylus asini , Strongylus vulgaris, Strongylus equinus and Strongylus edentatus, was studied with scanning electron microscopy (SEM). Fresh specimens of S. asini were collected from the caecum, ventral colon and vena portae of Equus burchelli and Equus zebra hartmannae ; S. vulgaris from the caecum, colon and arteria ileocolica of E. burchelli ; S. equinus from the ventral colon of E. z. hartmannae and S. edentatus from the caecum and ventral colon of both zebras , during surveys of parasites in zebras in the Etosha Game Reserve, South West Africa/Namibia, and the Kruger National Park, Republic of South Africa. The worms were cleaned, fixed and mounted by standard methods and photographed in a JEOL JSM - 35C scanning electron microscope (SEM) operating at 12kV . The SEM showed the following differences: the tips of the external leaf-crowns varied and were fine and delicate in S. asini , coarse and broad in S. vulgaris and, in S. equinus and S. edentatus, closely adherent, separating into single elements for half their length. The excretory pores showed only slight variation, and the morphology of the copulatory bursae did not differ from those seen with light microscopy. The genital cones differed markedly: S. asini had a ventral triangular projection and laterally 2 finger-like projections: in S. vulgaris there were numerous bosses on the lateral and ventral aspects of the cone; in S. equinus 2 finger-like processes projected laterocaudally ; and in S. edentatus 2 pairs of papilla-like processes projected laterally on the ventral aspects, and a pair of rounded projections and a pair of hair-like structures adorned the dorsal aspects.(ABSTRACT TRUNCATED AT 250 WORDS)
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Two helminth-free tracer calves were exposed to natural helminth infestation of a farm in the eastern Transvaal Lowveld for one month. On a nearby farm calves grazed with the herd for at least 3 months before slaughter so that the cumulative worm burden could be determined. The gastro-intestinal parasites increased markedly after rain. The major species and order or prevalence were: Cooperia pectinata, Cooperia punctata, Haemonchus placei and Oesophagostomum radiatum; minor species were Bunostomum phlebotomum, Trichostrongylus falculatus, Nematodirus helvetianus, Trichuris spp., Parafilaria bovicola and Paramphistomum spp. The highest worm burdens of Cooperia spp. on the first farm were between December and March and with the exception of O. radiatum, which had a peak in January, the other species reached peak worm burdens on the other farm in March.
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Infective larvae were harvested from a culture of eggs collected from adult Strongylus asini recovered from a free-ranging Burchell's zebra, Equus burchelli, in the Kruger National Park. Worm-free zebra, horse and donkey foals were successfully infested, but infestation failed in a mule foal. At slaughter, 117-125 days post-infestation, S. asini in their 4th moult were recovered from the liver and portal veins. This is the first report of successful experimental infestation of these hosts with S. asini.
The anthelmintic efficacy of fenbendazole, dosed to artificially infested cattle at 5 mg/kg live mass was determined against immature and adult Haemonchus placei. Ostertagia ostertagi, Cooperia spp., Bunostomum phlebotomum and Oesophagostomum radiatum. At this dosage rate, fenbendazole was more than 80% effective in more than 80% of the animals treated against the abovementioned nematodes. The only exception was against the third-stage larvae of B. phlebotomum when it fell to more than 60% effective in more than 60% of the animals treated.
A single oral dose of fenbendazole (FBZ) paste at 7,5 mg/kg body mass was given to 5 horses. It was highly effective against adults of the following genera: Cyathostomum, Cylicostephanus, Cylicondontophorus, Poteriostomum, Cylicocyclus, Triodontophorus, Oesophagodontus (and other genera belonging to the subfamily Cyathostominae). Similarly, high efficacy was obtained against the adults of the following species: Oxyuris equi, Strongylus vulgaris, Strongylus equinus and Probstmayria vivipara. These results were confirmed in 12 horses and in addition FBZ at 7,5 mg/kg was highly effective against Parascaris equorum, Craterostomum and Gyalocephalus.
The entire gastro-intestinal tract and viscera of the abdomen and thorax, including the heart, aorta and its branches to the viscera, are removed from the carcass. All the branches of the aorta, with the exception of the A. gastrica sinistra, are dissected from the intestinal tract, and subsequently each branch is isolated from the mesentery, fat, pancreas, kidneys, etc. Usually, the A. ileocolica is grossly enlarged due to chronic arteritis with thrombus formation caused by 4th stage larvae, 4th moult and 5th stage Strongylus vulgaris. Descriptions of methods to examine the subperitoneal tissues, liver and lungs are included.
The tongue, pharynx, oesophagus and gums are examined for larvae of gasterophilus spp., and the nose and sinuses for oestrid larvae. The gastro-intestinal tract is divided into separate specimens-stomach, small intestine, caecum, ventral colon, dorsal colon, descending colon and rectum- and each is examined separately. Aliquots of ingesta of 1/4 by mass of the stomach and 1/10 by mass of the small intestine, caecum, ventral colon and dorsal colon are collected for microscopic examination. Each part of the wall of the caecum, ventral and dorsal colon is washed and specimens are collected for subsequent examination. The gut wall of the caecum and colon is examined macroscopically for larval stages. Ingesta in the descending colon are examined macroscopically for Gasterophilus larvae.
A single oral dose of fenbendazole (FBZ) at 10mg/kg body mass was given to 5 donkeys. A further 5 donkeys were dosed with a medicated lick (1 mg FBZ/g lick) until the oral consumption was 10mg/kg body mass. In both trials FBZ was highly effective against adults of the following genera: Cyathostomum, Cylicocyelus, Cylicostephanus, Cylicodontophorus, Poteriostomum, Cabellonema, Craterostomum and Triodontophorus; similarly high efficiency was obtained against the following species: Habronema majus, Habronema musca, Strongylus vulgaris and Oxyuris equi and worms identified as belonging to the subfamily Cyathostostominae. These results were confirmed in horses and in addition FBZ at 10mg/kg was highly effective against Gyalocephalus capitatus, Oesophagodontos robustus and Parascaris equorum.
The anthelmintic efficacy of fenbendazole FBZ against Moniezia expansa was tested in sheep and cattle at a dosage rate of 10 mg FBZ per kg body mass. Twenty seven out of 30 lambs and 8 out of 12 calves were cured of the infestation.
Fenbedazole, dosed to artificially infested cattle at 7,5 mg/kg live mass, was more than 80% effective in more than 80% of the treated animals against immature and adult Haemonchus placei, Ostertagia ostertagi; Cooperia spp., Bunostomum phlebotum and Oesophagostomum radiatum.
A single oral dose of fenbendazole (FBZ) at 10 mg/kg body mass was given to 5 donkeys. A further 5 donkeys were dosed with a medicated lick (1 mg FBZ/g lick) until the oral consumption was 10 mg/kg body mass. In both trials FBZ was highly effective against adults of the following genera: Cyathostomum, Cylicocyclus, Cylicostephanus, Cylicodontophorus, Poteriostomum, Cabellonema, Craterostomum and Triodontophorus; similarly high efficiency was obtained against the following species: Habronema majus, Habronema musca, Strongylus vulgaris and Oxyuris equi and worms identified as belonging to the subfamily Cyathostominae. These results were confirmed in horses and in addition FBZ at 10 mg/kg was highly effective against Gyalocephalus capitatus, Oesophagodontos robustus and Parascaris equorum.