East coast fever: Further laboratory investigations on the use of rabbits as vehicles for infecting ticks with theilerial piroplasms

Summary A series of experiments was carried out in which attempts were made to achieve maximum survival ofTheileria parva-infected bovine erythrocytes in inoculated rabbits. By varying the treatment of the rabbits and of the erythrocytes and by altering the route of inoculation, it was finally shown that the best and most consistent results could be obtained by the intravenous inoculation of 20 ml of infected bovine blood into splenectomised rabbits. When nymphalRhipicephalus appendiculatus ticks were fed on such rabbits, the resultant adult ticks showed highTheileria parva infection rates in their salivary glands.

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Sumario Se llevaron a cabo una serie de experimentos tendientes a lograr el máximo de supervivencia de eritrocitos bovinos infectados conTheileria parva, en conejos inoculados. Variando el tratamiento de los conejos y eritrocitos, como también la ruta de inoculación, se demostró finalmente, que el resultado mejor y más consistente se obtuvo con la inoculación de conejos esplenectomizados con 20 ml de sangre infectada de bovino, via intravenosa.

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Résumé Une série d'expériences a été conduite pour déterminer le moyen le plus s?r d'assurer chez le lapin le maximum de survie auxTheileria parva d'érythrocytes de bovins infectés. En variant le traitement du lapin et des érythrocytes de boeufs, ainsi que les voies d'inoculation, les résultats les meilleurs et les plus réguliers ont été obtenus par inoculation intraveineuse de 20 ml de sang de bovin infecté à des lapins préalablement splénectomisés. Les nymphes deRhipicephalus appendiculatus nourries sur ces lapins donnent des tiques adultes dont les glandes salivaires sont fortement infectées parT. parva.

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On ODA secondment from the ARC Institute for Research on Animal Diseases, Compton, Nr. Newbury, Berkshire, UK (ODA Research Project R2396).

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On ODA secondment from the Central Veterinary Laboratory, New Haw, Weybridge, Surrey, UK.

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FAO Animal Health Officer.

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Project supported by the United Nations Development Programme with the Food and Agriculture Organization of the United Nations as the Executing Agency, in co-operation with the East African Community. The Project is also supported by the Overseas Development Administration of the United Kingdom (Research Projects R2396 and R2494), the United States Department of Agriculture, the International Atomic Energy Agency and the Pfizer Corporation.