Scanning electron microscopy of the tegumental surface of Heterobilharzia americana (Trematoda; Schistosomatidae)

An attempt is made in this paper to define more clearly the tegumental microstructure of the schistosome, Heterobilharzia americana. The adult parasites were examined with scanning electron microscopy at 75-10 000 magnifications. The morphology of the oral and ventral suckers, the tegument, and the gynecophoral canal with the in copula female were closely scrutinized. The tegument of the female is simple and uniform in structure, an adaptation which may allow for a more efficient mode of penetration through the smaller mesenteric venules. The male tegument, however, is characterized by papilla-like elevations of irregular size, shape, and distribution. These papillae may represent different kinds of sensory endings.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Studies on the parasites of zebra. II. Cylicostephanus longiconus n. sp. (Nematoda: Strongylidae) from the mountain zebra, Equus zebra hartmannae (Matschie , 1898)

A new species of nematode, Cylicostephanus longiconus, was collected from mountain zebra, Equus zebra hartmannae (Matschie, 1898), on the Kelpie farm in the Khomas Hochland, South West Africa/Namibia. These nematodes have 1 large dorsal and 2 small subventral teeth in the oesophageal funnel and submedian papillae with very long tips. The males have a very well-developed dermal collar and genital cone.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Studies on the parasites of zebras. 1. Nematodes of the Burchell's zebra in the Kruger National Park

Nineteen species of gastro-intestinal nematodes were recovered from 10 Burchell's zebra. These include: Cyathostomum alveatum, C. montgomeryi and C. tetracanthum; Cylicocyclus auriculatus, C. gyalocephaloides, C. insigne and C. triramosus; Cylicodontophorus schürmanni and Cylicodontophorus n. sp., Cylicostephanus bidentatus, C. calicatus and C. minutus; Poteriostomum ratzii, Craterostomum acuticaudatum, Triodontophorusminor, Habronema majus, H. muscae, H. zebrae, and Draschia megastoma, as well as Cylindropharynx spp. The highest burdens encountered were those of Cylicocyclus triramosus (159 491), Cylindropharynx (19 875), Cylicocyclus auriculatus (15 792), Cylicostephanus calicatus (16 658) and Cyathostomum tetracanthum (13 723). The nematodes consistently present in all zebras were: Cylicostephanus calicatus, Cylindropharynx spp. and Draschia megastoma.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Studies on the parasites of zebras. IV. Cylicodontophorus reineckei n.sp. (Nematoda: Strongylidae) from the Burchell's zebra, Equus burchelli antiquorum H. Smith, 1841 and the mountain zebra, Equus zebra hartmannae Matschie, 1898

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 Afrfca/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.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.am201

The recovery of helminths postmortem from equines. II. Helminths and larvae of Gasterophilus from the gastro-intestinal tract and oestrids from the sinuses.

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.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Scanning electron microscopy of Strongylus spp. in zebra

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. The most significant micrograph was the shedding of the cuticle of the 4th moult of a female S. asini.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.University of Pretoria. Council for Scientific and Industrial Research. Department of Agriculture and Fisheries of South Africa

Recovery of helminths postmortem from equines. I. Parasites in arteries, subperitoneum, liver and lungs

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 articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Studies on the parasites of zebras. III. Nematodes of the mountain zebra from the farm "Kelpie" and the Namib-Naukluft Park, South West Africa/Namibia

Twelve mountain zebra which were culled at monthly intervals on the farm "Kelpie" in South West Africa/Namibia were examined for helminths. The zebras varied in age from 2-15 years, the middle group of which, aged 4-7 years, had the highest worm burdens. Fourteen species of nematodes belonging to the families Atractidae, Strongylidae, Oxyuridae, Setariidae and Spiruridae were recovered. The highest worm burdens were those of Crossocephalus sp. with 692-61 066 680 and Probstmayria vivipara with 1 257 810-42 004 300. The predominance of the atractids is discussed. The nematodes consistently present were: Cylicodontophorus n. sp. (44-2 107), Triodontophorus spp. (2-934), Cylindropharynx spp. (20-2 332), Crossocephalus sp. and P. vivipara. Two new species, Cylicostephanus longiconus and Cylicodontophorus n. sp., were reported. An additional 3 mountain zebra, culled in the Namib-Naukluft Park, were also examined for helminths. Of 3 zebras ranging in age from 2- 7 years, the 2 older animals had the highest helminth burden. Ten species of the nematodes belonging to the same families mentioned above were recovered. The only Spiruridae present were 3 Habronema majus in 1 zebra. The highest worm burdens were those of Crossocephalus sp. With 64 052-883 070 and P. vivipara with 50 720-220 200. The nematodes consistently present were the same as those in the "Kelpie" zebra. In addition, a 2nd, new species of Cylicodontophorus was reportedThe articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Council for Scientific and Industrial Research. University of Pretoria

Studies on Haemonchus contortus. XII. Effect of Trichostrongylus axei in Dorper lambs on natural pasture lightly infested with H. contortus

Weaned Dorper lambs on natural pasture were predosed with 40 000 infective larvae (L₃) of Trichostrongylus axei, irradiated (0,3 kGy) L₃ of T. axei or closantel at 10 mg/kg either in September or November 1978 and were compared with Merino yearlings predosed with 40 000 L₃ of T. axei in November 1977. The following summer (December- March) only 178,6 mm of rain fell and very few H. contortus were present on pastures. Artificial challenge with 20 000 L₃ of Haemonchus contortus with the local strain from the University of Pretoria's experimental farm was given 6--7 months after predosing with T. axei. When compared with the controls, significant reductions occurred only in Group 11 (T. axei irradiated at 0,3 kGy on Day +63) (P=0,025); Group 2 (T. axei on Day 0) (P = 0,003) and Group 4 (T. axei and closantel on Day 0) (P = 0,049). We concluded that predosing with T. axei was unsuccessful in Dorpers and Merinos artificially challenged 6--7 months later with H. contortus.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Department of Agriculture.am201