DETECTION OF TOXOPLASMA-GONDII PARASITEMIA BY POLYMERASE CHAIN-REACTION IN PERORALLY INFECTED MICE

Sequential blood samples collected from mice infected perorally with a n avirulent strain of T. gondii were analysed for parasite DNA by a po lymerase chain reaction method (PCR). Two pairs of primers specific fo r gene B1 and he repetitive DNA sequence TGR1(E) were used for DNA amp lification. Amplified products were detected by means of electrophores is with ethidium bromide staining. Parasitemia was also determined by cell culture. Parasitemia was never detected by the tissue culture met hod, whereas parasite DNA was continously detected with PCR from day 2 to day 21. These results confirm the high sensitivity of PCR for T. g ondii DNA in blood, and show that circulating DNA is present for long periods in mice following primary infection.