Effect of the behavioural stress on susceptibility of Syrian hamsters to Schistosoma mansoni infection: effect on number and fertility of worm burden.

Effect of pairing on susceptibility of male Syrian hamsters to Schistosoma mansoni infection in comparison to their isolated counter-parts have been studied. Pairing resulted in significant differences between paired and isolated hamsters in measurements of eggs, miracidia, number of adult worms recovered and mean testicular number of males. Paired hamsters seemed to be immunologically suppressed and such a suppression resulted in increasing the fertility and number of worms recovered. The width of the male schistosomes recovered from the paired hamsters was two folds and the length was four folds greater than those recovered from isolated ones. The mean testicular number was 8.17 +/- 0.53 in males recovered from paired hamsters and 6.16 +/- 0.71 in those recovered from isolated ones. Of interest was, the demonstration of a male with two groups of testes recovered from a paired hamster. It was concluded that the stressed host reflex effects on the number and fertility of the schistosome worms burden, and hence the severity of the disease and its complications.