Trichinellosis in the exercised rat

Ahmad R. A. and Harpur R. P. 1982. Trichinellosis in the exercised rat. International Journal for Parasitology12: 59–63. Trichinella spiralis in Fischer (CDF/344) inbred rats was used to investigate the effect of exercise on a parasitic infection. Sixty male rats were trained for 2 months by running on a drum, a distance of 1.26 km day^?1 in 60 min (4 days week^?1) or 1.5 km in 90 min (5 days week^?1). They were then given 0, 100 or 500, and 0,100 or 1000 infective Trichinella spiralis larvae respectively; the numbers of larvae encysted in the muscle of the rats 4 weeks later were determined. Trained animals had a significantly lower body weight which they maintained for 3 weeks after exercise ceased, but the training had no effect on the larval recovery. Likewise, exercise for 4 weeks after inoculation (i.e. during the chronic and invasive phases) had no effect. It is concluded that exercise does not modify the resistance of the rat to T. spiralis infection. It is difficult to separate the effects of exercise from the stress caused by exercise but because the rat-T. spiralis system is shown to be relatively insensitive to stress it is a good model with which to look for the effects of exercise per se.