The role of Hyalomma ticks in foot infestations and temporary lameness of sheep in a semi-arid region of South Africa

Show simple item record Kok, D.J. Fourie, L.J.
dc.contributor.editor Verwoerd, Daniel Wynand 2013-09-09T11:23:57Z 2013-09-09T11:23:57Z 2013 1995
dc.description 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. en
dc.description.abstract An outbreak of lameness amongst Merino lambs, associated with the presence of Hyalomma ticks, was investigated on a farm in the south-western Free State, South Africa. The purpose was to follow the progress of the condition and to determine the extent of involvement of the two Hyalomma species which occur in the region. The flock of experimental sheep (n = 460) ranged free in natural veld under extensive farming conditions. During September and October 1993, adult ewes and lambs in this flock were examined at weekly intervals to determine tick identity, abundance and attachment-site preferences on lame and unaffected animals. Lameness occurred only among lambs, of which 68 were affected during the 8-week period. Hyalomma ticks tended to aggregate and mean numbers of ticks/aggregation were significantly higher on lame lambs (mean = 11,3) than on either the unaffected lambs (mean = 6,9) or the ewes (mean = 7,1). Most tick aggregations (72,4%) on the lame lambs occurred on the lower legs and feet, 34 out of 55 of these on the fetlocks or interdigital clefts. Hyalomma truncatum dominated (> 97%) on all animals examined. Only 15,8% of the Hyalomma marginatum rufipes recovered from the lame animals were attached to the legs. At two other localities at which H. marginatum rufipes was more abundant, or even dominant, few ticks attached to the lower legs or feet. Those that did were mostly H. truncatum (> 90%). Both H. marginatum rufipes and H. truncatum may attach to the same ventral and anogenital body regions, but H. truncatum has a tendency to attach also to the feet and lower legs. Although attachment of one or a few ticks in the axillar region or upper legs may cause lameness in sheep, the attachment of ticks to the interdigital clefts and fetlocks almost always causes lameness. The latter condition is more likely to occur in regions where H. truncatum dominates. en
dc.description.librarian mn2013
dc.description.sponsorship University of the Orange Free State. Foundation for Research Development. Poliomyelitis Research Foundation. en
dc.identifier.citation Kok, DJ & Fourie, LJ 1995, 'The role of Hyalomma ticks in foot infestations and temporary lameness of sheep in a semi-arid region of South Africa’. Onderstepoort Journal of Veterinary Research, vol. 62, no. 3, pp. 201-206. en
dc.identifier.issn 0330-2465
dc.language.iso en en
dc.publisher Published by the Agricultural Research Council, Onderstepoort Veterinary Institute en
dc.rights © ARC-Onderstepoort (original). © University of Pretoria. Dept of Library Services (digital). en
dc.subject Veterinary medicine en
dc.subject Hyalomma en
dc.subject Foot infestations en
dc.subject Temporary lameness en
dc.subject Sheep en
dc.subject Semi-arid region en
dc.subject.lcc Ticks as carriers of disease en
dc.subject.lcsh Veterinary medicine -- South Africa
dc.title The role of Hyalomma ticks in foot infestations and temporary lameness of sheep in a semi-arid region of South Africa en
dc.type Article en

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