Detection of Toxoplasma gondii by polymerase chain reaction in sera of acutely infected mice

The presence of Toxoplasma gondii DNA was detected in sera of acutely infec ted mice by polymerase chain reaction. Adult mice were inoculated intraperi toneally with 5 x 10(3) T. gondii RH strain tachyzoites. Five mice were kil led every 3 hr from 3 to 21 hr post infection (PI) and every day from 1 to 7 days PI. Toxoplasma gondii DNA was first detected in 60% of the infected mice 18 hr PI and in 100% of the animals 21 hr PI and from 1 to 7 days PI. No mice survived longer than 7 days.