[Comparative study of experimental pathogenicity of Acanthamoeba strains (author's transl)].

We have tested pathogenicity on mice after the intranasal instillation of 8 Acanthamoeba strains isolated from swimming-pools. The A1 strain of A. culbertsoni has also been tested as pathogenic reference strain. Virulence is measured by determination of D.L. 50 for each strain from the study of the variation of mortality in relation to the inoculated dose. We have established that the most of Acanthamoeba strains (6 on 8) isolated from an external environment (swimming-pools) are able to kill a certain percentage of mice after intranasal instillation. But the potential pathogenicity revealed in this way varies greatly (D.L. 50 included between 4.10(2) and 4.10(5)) from one strain to another. Elsewhere there seems to be no correlation among Acanthamoeba between the observed pathogenicity and the fact that it belongs to a particular species.