Experimental transmission of Cowdria ruminantium (Rickettsiales) by the American reptile tick Amblyomma dissimile Koch, 1844.

A Senegalese isolate of the rickettsia Cowdria ruminantium was transmitted transstadially by nymphs of the American reptile tick Amblyomma dissimile. Only eight nymphs, fed as larvae on a Saanen goat reacting to heartwater, were required to transmit fatal heartwater to another susceptible goat. Since A. dissimile usually feeds on snakes, iguanas and lizards in central America, the tick is not considered to play a significant role in the transmission of heartwater between ruminants. However, the tick could play a role in maintaining a rickettsial reservoir in reptile populations, since it has been shown that an African reptile can be a subclinical carrier of C. ruminantium, infective to vector ticks.