Three stimuli, elevated temperature, hydrogen peroxide and mebendazole, were compared for their ability to induce heat-shock responses in Trichinella spiralis muscle larvae (L1). In vitro effectiveness of each 'stressor' was evaluated by viability score, protein content and levels of hsp90, hsp70 and hsp60. Detection of the respective heat-shock proteins was done by Western blotting and the heat-shock proteins and quantitation of the immunoblots by image analysis. Exposure of L1 to elevated temperature (e.g. 45 degrees C, 2 h) had no measurable effect. However, exposure to hydrogen peroxide resulted in the induction of constitutive and higher mol. wt heat-shock proteins. In these experiments, heat-shock protein induction correlated strongly with other damage parameters, including loss of viability and increased mortality. Larvae stored in the presence of mebendazole showed no signs of damage. These data indicate that when L1 suffer damage through the action of stimuli, enhancement of heat-shock protein production and damage suffered are causally related.