Prevention of abortion and neonatal death due to toxoplasmosis by vaccination of goats with the nonpathogenic coccidium hammondia hammondi.

Six does serologically negative to toxoplasma gondii were vaccinated with 1 million oocysts of the nonpathogenic coccidiym Hammondia hammondi 17 to 73 days before breeding. Two does were not inoculated with H hammondi. All does were mated with a T gondii-free buck. Between the 51st and 119th days of their pregnancies, 5 of the 6 Hammondia-vaccinated does and the 2 controls were each inoculated orally with 1,000 infective oocysts of the GT-1 strain of T gondii. Four of the 5 Toxoplasma-inoculated vaccinated does gave birth to 8 apparently healthy kids at the expected gestation period. The 5th vaccinated doe gave birth to 3 kids that died during delivery or were born dead. Toxoplasma gondii was isolated in mice inoculated with tissues of all kids born to vaccinated does. The vaccinated doe which was not inoculated with T gondii gave birth to 2 healthy noninfected kids. Of the 2 control pregnant does (not vaccinated, but inoculated with T gondii), 1 aborted due to toxoplasmosis 17 days after inoculation. The other control doe had 2 dead fetuses and retained fetal membranes in uterus when necropsied at the expected parturition time. the results indicate that it might be possible to develop a vaccine against toxoplasmic abortions in animals.