Further characterization of the TS-4 temperature-sensitive mutant of Toxoplasma gondii in mice.
Maternal transmission of Toxoplasma gondii infection to fetuses is important in human and veterinary medicine. Animals, including mice, have been successfully vaccinated with living tachyzoites of the avirulent, nonpersistent, TS-4 temperature-sensitive mutant of T. gondii and have survived challenge infections. We examined in the murine model the persistence of TS-4 infection, transplacental and transmammary transmission, and virulence in neonates. Bioassays of mouse tissues and histological examination of tissues indicated that no viable organisms were present beyond 14 days after inoculation in adult female mice. The TS-4 mutant was not transmitted transplacentally in mice inoculated at 5, 10, or 15 days of gestation and not transmammarily transmitted in mice inoculated 2 days postpartum. Four groups of mouse pups were inoculated subcutaneously with 2 x 10(4), 2 x 10(5) tachyzoites, or with Hanks' balanced salt solution at 2, 3, or 10 days of age. Severe clinical disease and death were observed in 2- or 3-day-old mice and moderate to severe disease was observed in the 10-day-old mice. Results indicate that the TS-4 mutant can cause disease in young nursing mice but is avirulent for pregnant or nonpregnant adult mice.
Pinckney
R D
RD
Department of Pathobiology, College of Veterinary Medicine, Auburn University, Alabama 36849-5519.
Lindsay
D S
DS
Blagburn
B L
BL
D000818:Animals; D000831:Animals, Newborn; D000833:Animals, Suckling; D000913:Antibodies, Protozoan / Q000097:blood; D004195:Disease Models, Animal; D005260:Female; D018445:Infectious Disease Transmission, Vertical; D051379:Mice; D009154:Mutation; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000469:parasitology*; D013696:Temperature; D014122:Toxoplasma / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*; D014124:Toxoplasmosis, Animal / Q000469:parasitology* / Q000635:transmission; D014125:Toxoplasmosis, Congenital / Q000209:etiology*; D014774:Virulence
D000913:Antibodies, Protozoan