Evaluation of jackrabbits as nonruminant hosts for Anaplasma marginale

Two black-tailed jackrabbits (Lepus californicus), 1 splenectomized and 1 intact, were inoculated with 0.2 ml of a 1:5 dilution of a Florida Anaplasma marginale stabilate. Five months later, both hares were inoculated with 1 ml of whole blood from a calf with acute anaplasmosis. Neither hare developed any signs of clinical anaplasmosis. Pooled blood (7 ml) from these jackrabbits which was inoculated into 2 Anaplasma-susceptible, splenectomized calves failed to induce hematologic or serologic signs of anaplasmosis for at least 90 days. Two susceptible, splenectomized calves were inoculated with 35 ml of pooled whole blood from 9 wild-collected black-tailed jackrabbits from a known anaplasmosis enzootic area. Both steers remained free of anaplasmosis signs for 90 days.