Blood collected in either sodium heparin or disodium edetate vacutainers from febrile goats infected with 4 isolates of Cowdria ruminantium and cryopreserved with 10% dimethyl sulphoxide at -70 degrees C and -196 degrees C was an effective stabilate to initiate heartwater infections in goats. A homogenized pool of whole Amblyomma variegatum ticks in Snyder's buffer, maintained at -196 degrees C, was used to infect a goat with C. ruminantium. Liver and spleen collected from Swiss mice infected with the Kwanyanga isolate of C. ruminantium were homogenized in Snyder's buffer, maintained at -196 degrees C and were used to initiate infections in mice. Fresh blood collected from febrile goats and maintained at 4 degrees C for as long as 72 h was infectious to mice. Neutrophils separated from blood of C. ruminantium infected goats and maintained in modified RPMI medium at 37 degrees C for 68 h were infectious for a goat. Similarly neutrophils from a 2nd infected goat maintained for 96 h at 37 degrees C were infectious for mice.