Virulence in mice of atypical Toxoplasma gondii strains isolated in French Guiana compared to reference strains (type I, II and III). Ten mice/groups were inoculated intraperitoneally with different doses of tachyzoites for each strain, and the viability of mice was monitored daily. Survival was followed up for 31 days after injection and data were plotted as Kaplan-Meier curves (statistical significance of survival curves between RH and others strains, p ≤ 0.001).