Large Babesia species transmitted to splenectomized calves by field collections of British ticks (Haemaphysalis punctata).

Abstract

BETWEEN 1902, when it was first established that babesiosis (redwater) in Britain was caused by a piroplasm1, and 1911 it was thought that the common cause of this disease was Babesia bigemina, a large piroplasm. In 1911, M'Fadyean and Stockman described2 a small piroplasm, Babesia divergens, from British cattle. During 1968 the original colour paintings used by M'Fadyean and Stockman were given to one of us and a study of the early literature that these illustrations stimulated suggested that a large Babesia species, like B. bigemina, really did exist in British cattle in the early years of this century. Because the large Babesia has not been seen since 1911 it has been thought that M'Fadyean and Stockman were mistaken or that the large Babesia they depicted had been imported from South Africa and had contaminated their experimental animals. Their colour paintings were reproduced in a paper3 calling attention to the possibility that the large Babesia might still be present in Britain, and that this might be so is supported by Dutch literature4,5 which describes the rediscovery of a large Babesia in cattle in the Netherlands and its identification with Babesia major, a large piroplasm first described in 19266.