Isolation of a virulent strain of Ehrlichia phagocytophila from the blood of cattle in the Isle of Man.

A blood sample from a cow in the Isle of Man caused a severe Ehrlichia phagocytophila infection when inoculated into a splenectomised calf. The parasite was passaged successively into a further splenectomised calf and then into two intact animals. One of the splenectomised calves and one of the intact animals died of the infection which was characterised by causing a sustained febrile response apparently correlated with a marked invasion of monocytes by the rickettsiae.