[Comparison between the official indirect method and the direct method of control of vaccines against sheep enterotoxemia].

The official methods of control of vaccines against sheep enterotoxemia are indirect in two ways : on the one hand they are carried out on animals for which the vaccine is not intended, and on the other hand they test only an immunological serum reaction. Another method consisting of direct testing by intravenous injection of toxin has been carried out on mice previously vaccinated with different doses. It has been shown that it is possible to obtain a certain level of protection giving a good dose-effect relation. However, immunity provided by this direct method is weak although the vaccine utilized is considered very efficacious with regard to the official norms of the direct test. These results, which are both encouraging and disappointing, will be the subject of a more intensive study of the different parameters in question.