Abstract: 　Objective To study the curative effect of praziquantel against juveniles of Paragonimus westermani and the dynamic changes of T lymphocytes and their subpopulations in infected mice after treatment. Methods Mice infected with metacercariae of P. westermani were treated with praziquantel 10 days after infection for examining the curative effect. Results Mice infected orally each with 30 metacereariae of F. westermani were treated with praziquantel at doses of 400,500 and 600 mg/(kg·d) respectively for 3 d, the juvenile reduction rates were 71.01 % ± 10.38% ,82.29% ± 7.92% and 95.83% ± 3.24% respectively; when the mice were infected with 80 metacercariae and treated with a dose of praziquantel 600 mg/(kg·d) for 3 d, the worm reduction rate was 84.49% ±10.91%. T lymphocytes and their subpopulations began to increase at 1 wk and returned to normal at 8 wk after praziquantel treatment. Conclusion The efficacy of praziquantel against juvenile P. westermani was poorer than that against adult worms ; the efficacy was relevant to the drug dosage and the number of metacercariae infected. The T lymphocytes and their subpopulations may be regarded as an index for curative effect.

Key words: Paragonimus westermani, mouse, praziquantel, T lymphocyte, subpopulation