Experiments with English and South African redwater

Abstract

Conclusions: It would be seen from these notes that of four animals inoculated with English redwater, two failed to react or to show piroplasms, and in the other two instances a reaction ensued, accompanied with the appearance of piroplasms. Therefore it is safe to say that English redwater is not always inoculable, and differs in this respect from South African redwater. I do not feel justified in drawing any conclusions from the results of the injection of heifers 400, 418, 421 and 422 with blood of English heifer No. 428, for, as will be seen from Experiment 1, "A," this heifer did not appear to contract the infection in England, as no piroplasms were seen, due to an inoculation of English redwater blood, and the reaction was atypical. I therefore consider that the failure of heifer 428 to contract English redwater from the injection of virulent blood is another point in favour of my contention that English redwater is not always inoculable. The results obtained from the other five heifers, however, seem to be conclusive, as heifer 430 was certainly infected with English redwater.Therefore English redwater was not inoculable in our five South African heifers, and accordingly when tested they all contracted ordinary redwater, proving that they had not acquired any immunity against South African redwater.