Studies on schistosomiasis. 8. The influence of age on the susceptibility of sheep to infestation with Schistosoma mattheei

Show simple item record Van Wyk, J.A. (Jan Aucamp) Van Rensburg, L.J. Heitmann, L.P.
dc.contributor.editor Bigalke, R.D.
dc.contributor.editor Cameron, Colin McKenzie
dc.contributor.editor Gilchrist, Frances M.C.
dc.contributor.editor Morren, A.J.
dc.contributor.editor Verster, Anna J.M.
dc.contributor.editor Verwoerd, Daniel Wynand
dc.contributor.editor Walker, Jane B.
dc.contributor.other De Kock, V.E. 2016-07-06T11:08:47Z 2016-07-06T11:08:47Z 2016 1976
dc.description The articles have been scanned in colour with a HP scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to final presentyation PDF-Format. en_ZA
dc.description.abstract Twenty-eight Dorper wethers, allocated according to age into 4 groups of 7 animals each, and 1 group of 7 Merino wethers, were compared for susceptibility to Schistosoma mattheei infestation. The group mean ages of the Dorper sheep varied from 5-61 months and their live mass from 25-66 kg, while the Merinos were 8 months old and had a mean mass of 19 kg. Despite the marked differences in the age and live mass of the Dorper sheep and the inclusion of 2 breeds in the experiment, no statistically significant differences were found in cercariae which failed to penetrate the sheep the mean percentage development of cercariae to adult worms, worm distribution in the mesenteric and gastric radicles of the portal vein and the pulmonary arterial system, and worms not removed by perfusion. Significant differences between groups (5% significance level) were found, however, in the number of worms recovered from the hepatic portal system, and in the worm sex ratio. On 3 occasions the total number of eggs excreted per female schistosome in the mesentery per 24 hours differed significantly between groups, but each time a different group or groups of sheep were responsible for the variation which was probably due, therefore, not to the age or breed of the sheep, but to daily variations in individuals. Highly significant differences occurred in the infectivity of the 6 cercarial pools used for infestation in spite of standardized collection and handling of the cercariae. Possible reasons for this are discussed and a solution suggested. Frequent egg counts (5 per sheep per week) were done during the first 25 days of patency, until the sheep were slaughtered. Schistosome ova were detected in the faeces of only 1/18 sheep examined on Day +43 after infestation, and 3/17 on Day +44, whereafter this increased rapidly to 15/34 on Day +45, 25/33 on Day +46, etc. A highly significant correlation was found between the total worm egg excretion in the faeces of the sheep per day and the numbers of female schistosomes in the mesentery, especially shortly after the onset of egg production. en_ZA
dc.identifier.citation Van Wyk, JA, Van Rensburg, LJ & Heitmann, LP 1976, 'Studies on schistosomiasis. 8. The influence of age on the susceptibility of sheep to infestation with Schistosoma mattheei’, The Onderstepoort Journal of Veterinary Research, vol. 43, no. 2, pp. 43-54. en_ZA
dc.identifier.issn 0330-2465
dc.language.iso en en_ZA
dc.publisher Published by The Government Printer, Pretoria en_ZA
dc.rights ©1976 ARC - Onderstepoort and Faculty of Veterinary Science, University of Pretoria (original). ©2016 University of Pretoria. Department of Library Services (digital). en_ZA
dc.subject Veterinary medicine en_ZA
dc.subject.lcsh Veterinary medicine -- South Africa
dc.title Studies on schistosomiasis. 8. The influence of age on the susceptibility of sheep to infestation with Schistosoma mattheei en_ZA
dc.type Article en_ZA

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