Besnoitiosis in Australian wildlife and significance to cattle

Summary

A previous study of South Australian cattle published in 2012 demonstrated low level antibodies to Besnoitia besnoiti in a large proportion of the surveyed cattle. At the same time, Western Grey kangaroos in South and Western Australia had been reported to be suffering, and occasionally dying from nose-bleeds (epistaxis), and the presence of Besnoitia-like organisms demonstrated in the nasal flushes of these clinical cases. 
 Investigations of one property in the Tailem Bend area of South Australia and of a serum bank of a further 299 sera by serological (ELISA and Western Blot) means and with molecular tools (PCR) demonstrated that these Besnoitia-like organisms were not Besnoitia besnoiti. Attempts were made to isolate the organisms and a cell culture was established from a macropod animal (pouch-young of a Yellow-footed rock wallaby, grown at 35oC). 
Unfortunately no more fresh clinical cases have since become available, and isolation efforts have as yet been unsuccessful. In the meantime, there have been reports from Europe that the initial ELISA used in the first South Australian cattle study has also caused non-specific reactions in European surveys and has since been improved. B besnoiti, the cause of Elephant Skin Disease in cattle, has been reported as re-emerging as a major disease in recent years. 
Thus, in conclusion: while the exact nature and identity of the Besnoitia-like organisms involved in the nose-bleeds of Western Grey kangaroos could not (yet) be accomplished, the evidence suggests it not to be the Besnoitia besnoiti of cattle and should therefore not be considered to be a known threat to the Australian cattle industry.