Further notes on immunity in horsesickness

Abstract

The full history of the treatment accorded to each animal is apparent from the tables. Conclusion : These experiments show conclusively that when a horse or mule is inoculated with a certain strain of virus, the animal, as a rule, is immune against that particular strain, but when the animal is tested or hyperimmunised at a later date with virus of a different strain, reactions and deaths are noted, thus proving that the immunity afforded by the first inoculation is in no way complete. The last table shows the percentage of reactions (including doubtful reaction and dikkop) and deaths amongst the inoculated mules and horses included in the previous experiments. This table is compiled according to the number of the test (1st, 2nd, 3rd, etc.), and irrespective of the virus with which they were immunised or tested, and will serve as an indication of the results to be expected in practice. It is particularly instructive as demonstrating the difference between the immunity in horses and mules when obtained under the same conditions.