Reversion is the most important disease of black currant crops world-wide yet, despite research over more than 70 years, the causal agent of this disease has not been identified. The isolation of a new virus from reverted black currant, which had a very close association with the two recognised forms of black currant reversion disease, and was detected in vector gall mites from reverted plants and in plants on which such mites had fed, has been reported. These data suggest that this virus, tentatively called black currant reversion associated virus (BRAV), may be the causal agent of reversion disease. The detection of BRAV by immuno-capture reverse-transcriptase PCR (IC-RT-PCR) in redcurrant and in the wild species, Ribes spicatum and R. alpinum, other known hosts of the reversion agent, but not in the non-host, gooseberry, graft-inoculated with scions from reverted black currant plants is reported. The erratic distribution of BRAV in reversion-affected black currant plants, another characteristic of the reversion agent, is also reported. Taken together with earlier findings, these new data add further support to the suggestion that BRAV is the causal agent of reversion disease. The ways in which changes to the various parameters of sample preparation and of the IC-RT-PCR protocol affect the sensitivity of BRAV detection are discussed.