Some effects of 60Co irradiation on Cowdria ruminantium in its tick host Amblyomma hebraeum Koch (Acarina: Ixodidae).
An attempt was made to attenuate Cowdria ruminantium by irradiation of the nymphal stage of its tick host, Amblyomma hebraeum. The irradiated nymphs were homogenized and serial dilutions of the resultant suspension were injected intravenously into heartwater-susceptible sheep. No attenuation could be demonstrated but the results indicate that progressively more micro-organisms will be destroyed the higher the irradiation dosage applied, and that dosages between 20 and 30 kilorad apparently prove fatal to all the pathogenic organisms.