Heartwater in the Caribbean: isolation of Cowdria ruminantium from Antigua.

Adult Ambylomma variegatum ticks were collected from 184 cattle, 13 sheep and one goat in Antigua, and ground in phosphate buffered saline. The resultant supernates were cryopreserved in liquid nitrogen. Five supernate pools, each derived from approximately 100 ticks collected from different herds, were thawed and each was inoculated intravenously into a separate experimental goat. One goat exhibited a febrile response with Cowdria ruminantium demonstrable in brain biopsies; after recovery, this animal showed no reaction to a lethal challenge with a Guadeloupe isolate of C ruminantium.