The reproductive capacity index for Trichinella pseudospiralis infective larvae was similar for worms isolated from mouse carcasses on the day upon which mice were killed (day 0: 104.4 +/- 18.6 [mean +/- SD]) and on day 5 following mouse death (106.1 +/- 23.6), but was reduced for worms recovered from carcasses on day 10 postkill (PK: 22.7 +/- 5.7). Larvae isolated from mouse carcasses held at 24 C after day 10 PK were not infective. The percentage of viable worms (tightly coiled or moving) isolated from carrion was similar on days 0 and 5 PK but had declined to 40.4% by day 10 PK and showed a further reduction to 11.8% for worms isolated from carrion on day 15 PK. Viable worms were not recovered from carcasses after day 15 PK.