Please be advised that the site will be down for maintenance on Sunday, September 1, 2024, from 08:00 to 18:00, and again on Monday, September 2, 2024, from 08:00 to 09:00. We apologize for any inconvenience this may cause.
dc.contributor.author | Theiler, Arnold, Sir, 1867-1936![]() |
|
dc.contributor.editor | Union of South Africa. Dept. of Agriculture | |
dc.date.accessioned | 2009-09-17T08:05:00Z | |
dc.date.available | 2009-09-17T08:05:00Z | |
dc.date.issued | 1911 | |
dc.description | The journals have been scanned with a SupraScan 10000RGB scanner; 24-bit true colour, 400 dpi, saved in TIFF-format. Copies of the master images have been converted to black & white, 1-bitmap images and OCRed with ABBYY Fine Reader v.9 software. Adobe Acrobat v.9 was used for the merging and conversion to the final presentation PDF-format. | en |
dc.description.abstract | In the experiments it has been proved: (1) That brown tick imagines which as larvae had become infected with East Coast fever and which had transmitted the disease in their nymphal stage were no longer infective for susceptible cattle. Four batches of ticks proved their infectivity in the nymphal stage on eight animals, but in their adult stage failed to transmit the disease to two susceptible animals. (2) Ticks belonging to the same batches which were feeding on two animals rendered immune to East Coast fever by inoculation in the nymphal stage did not transmit the disease in their adult stage to six animals, thus proving that the brown tick which has become infected in one stage cleans itself in the following stage by feeding on an immune or susceptible animal. (3) Ticks which became infected with East Coast fever in their larval stage and which passed their nymphal stage on a rabbit did not prove to be infective in their adult stage for susceptible cattle. This conclusion bears out that given above (2): showing that a tick loses its infectivity the first time it feeds on an animal susceptible or immune to East Coast fever. (4) Clean or infective ticks feeding on an animal which has recovered from an attack of East Coast fever do not transmit the disease in their next stage. This conclusion is in support of experiments undertaken eight years ago (vide Annual Report of the Government Veterinary Bacteriologist, 1904-05). (5) It has been demonstrated that certain batches of ticks collected at the same time and which fed under similar conditions do not transmit the disease in their next stage, even when infested in great numbers and on numerous animals. Other batches of ticks reared in exactly the same way and under similar conditions only infected a few animals, whilst again other ticks proved infective in almost every instance even when a minimum number were used. It is difficult to give an explanation of this fact, but it is quite likely that outside conditions have some influence. The ticks which did not transmit the disease were bred during the coldest time of the year. This may perhaps explain the fact that during the winter months the infection in the field is not so active as during the summer months, remembering at the same time that during the winter months tick life is generally weaker than in the summer. | en |
dc.description.sponsorship | The Equine Research Centre, Faculty of Veterinary Science, University of Pretoria gave financial support to this digitisation project. | en |
dc.format.extent | The report consists of 15 pages. | en |
dc.identifier.citation | Theiler, A 1911, 'Some observations concerning the transmission of East Coast fever by ticks', First Report of the Director of Veterinary Research, pp. 208-222. | en |
dc.identifier.uri | http://hdl.handle.net/2263/11307 | |
dc.language.iso | en | en |
dc.publisher | Pretoria : Government Printer and Stationery Office | en |
dc.rights | ©Union of South Africa, Dept. of Agriculture (original). ©University of Pretoria. Dept. of Library Services (digital). | en |
dc.subject | Veterinary medicine | en |
dc.subject | Veterinary reports | en |
dc.subject | South Africa | en |
dc.subject | Theileria parva | en |
dc.subject | Rhipicephalus | en |
dc.subject.lcsh | East Coast fever -- South Africa | en |
dc.subject.lcsh | Veterinary medicine -- South Africa | en |
dc.subject.lcsh | Theileria parva -- South Africa | en |
dc.title | Some observations concerning the transmission of East Coast fever by ticks | en |
dc.type | Technical Report | en |