VOL. 22.1972 MINUTES 403 onomy. The chairman of the Subgroup on relationships of the toxoplasmas. of Toxoplasma presented a progress Minute 8. Next meeting. The next meeting of report. this subcommittee will be held in conjunction Minute 6. Acceptance of a standard antitoxo- with the next International Congress. plasma serum. After an international assay had Minute 9. Open meeting. An open meeting of been carried out under the auspices of an the subcommittee was held on 11 August 1970. Expert WHO Committee, a standard antitoxo- Minute 10. Present membership. The present plasma serum was accepted by the Biological membership of the subcommittee is as follows: Standardization Committee. This serum is sup- J. Chr. Siim (Chairman), Copenhagen, Den- plied on demand from the Department of mark; C. R. Cole, Columbus, Ohio, USA; H. A. Standardization at the State Serum Institute in Feldman, Syracuse, New York, USA; P. C. C. Copenhagen. The establishment of reference Garnham, Berkshire, England; D. N. Zasukhin, laboratories in different geographic areas was Moscow, USSR. recommended but has not yet been imple- Minute 11. Adjournment. The meeting was mented. adjourned. Minute 7. Future work. Future work will continue the attempts to define the biological J. Chr. Siim, Chairman

Report (1969-1970) of the Subgroup on Taxonomy of Toxoplasma of the Subcommittee on the Genus Toxoplasma

14 August 1970

Mexico City, Mexico

Since the last informal meeting of the accordance with the new “Rcgles.” However, subcommittee in Leningrad in July 1969, the the similarity in the structure of the oocyst problem of the classification of Toxoplasma has does not necessarily mean that the genera are become clearer because of new discoveries the same. For example, there are several concerning the life cycle of the organism. compartments in Hoare’s table of the The research began when Hutchison showed which contain more than one genus (e.g., in 1965 that the feces of cats, which had been Pfeifferinella, Schellackia, Tyzzeria). The pro- fed cysts of , contained a found differences in the life cycle of Toxo- resistant, long-lived, infectious form of the plasma (with its extra or aberrant cystic and organism. pseudocystic development, involving multiplica- It was finally proved late in 1969 that the tion by endodyogeny) clearly indicate that it is nature of this form was coccidian, first by Siim, not , though when the full life cycle of Hutchison, and Work, and almost simul- certain species of the latter are known (e.g., I. taneously by Frenkel and Dubey, and by hominis and I. bigemina), it may be necessary Sheffield. The work was further confirmed by to remove them to Toxoplasma. observers in Germany (Piekarski, Werner, At present, therefore, it would seem unwise Janitschke, and Weiland), in Holland (Over- to interfere with the present name of Toxo- dulve), and in Hawaii (Wallace). plasma. It is necessary, however, to remove this Oocysts seen in the cat’s feces possessed a genus from the subclass Toxoplasmatea, which disporocystic, tetrazoic structure, and the was created for it by Biocca, and place it in the endogenous stages were those of a typical Coccidia. Scholtyseck et al. have proposed the coccidian with rapid schizogony and game- creation of a new family, Endodyococcidia. togony throughout the small intestine. The positions of the other genera in the Some workers at once jumped to the subclass Toxoplasmatea-, Fren kelia, conclusion that the genus Toxoplasma would and remain obscure at present, and it have to be replaced by the genus Isospora, would probably be better to defer the introduc- owing to the structure of the oocyst, and this tion of new names until further investigations was attempted in a publication by Overdulve are completed on the whole group. (1 970). It was a “conditional proposal,” not in P. C. C. Garnham