Resumo

MITSUKA, Regina et al. Toxoplasma gondii: I. Evaluation of the virulence of eight strains. Braz. J. Vet. Res. Anim. Sci. [online]. 1998, vol.35, n.1, pp. 00-00. ISSN 1413-9596.  http://dx.doi.org/10.1590/S1413-95961998000100005.

In order to evaluate the virulence and pathogenicity of tachyzoites, eight Toxoplasma gondii strains isolated from different animal species and humans - LIV IV, LIV V e S 11 isolated from swine, RH e VPS from humans, AS 28 from mice, HV III from dog and CN from cat - were inoculated in mice and rabbits. All the strains were strongly virulent for mice. Groups of mice inoculated, intraperitonially, with 10⁴ tachyzoites died in an average of 6.0 to 7.8 days, after inoculation. The strains isolated more recently, LIV V and HV III (LD₅₀ of 7 and 15 tachyzoites, respectively) were the most virulent. The RH strain showed the lowest virulence, with LD₅₀ of 3160 tachyzoites. The LIV V strain also seems to be most virulent to rabbits.

Palavras-chave : Toxoplasma gondii; Pathogenicity; Laboratory animals.