Radley, D.E.Brown, C.G.D.Cunnigham, M.P.Kimber, C.D.Musisi, F.L.Purnell, R.E.Stagg, S.M.2015-07-142015-07-141975Radley, D.E., Brown, C.G.D., Cunnigham, M.P., Kimber, C.D., Musisi, F.L., Purnell, R.E., Stagg, S.M. (1975). East Coast Fever: Challenge if Immunised Cattle by Prolonged Exposure to Infected Ticks. The Veterinary record, 96(24), 525-527.0019-2805https://kalroerepository.kalro.org/handle/0/4310Bos taurus steers, previously treated with acaricide but washed before the trial commenced, were introduced sequentially to a paddock with a high level of T. parva infected ticks. The 12 animals exhibited macroschizonts in lymph nodes at 7-12 days, a febrile response at 9-13 days, and died at 14-21 days. Tick counts were highest on ears (the maximum level was 330), and the build-up of tick attachment correlated with time to death. Four steers immunized three months previously with tick-derived T. parva stabilate material plus Terramycin ECF were kept in the paddock throughout the experiment (60 days). Prepatent period was 10-15 days, but despite high levels of tick attachment (peaks of 500 on ears), there were minimal symptoms and only a slight transient rise in antibody titre on day 40. A few macroschizonts were detected in lymph nodes during the first week of infection and they reappeared from days 34-38. A few piroplasms were seen intermittently in blood smears.enhttp://creativecommons.org/licenses/by/3.0/Journal ContributionEast coast feverCattleTicksSunlight exposure