Effect of schistosomiasis mansoni on open-field exploratory behavior in mice.

The response of mice infected with Schistosoma mansoni to a novel environment has been investigated in an attempt to study the effects of the disease on brain cognitive function by using opto-varimix instrument and autotrack computer program. Two to 18 weeks infected mice showed lower ambulatory activities than their matched controls with the largest reduction occurring between weeks 6 to 10. Maximum effects were observed in week 8. The first 5 minutes of ambulatory activities, designated as the "first session", were 22.3% lower in infected mice as compared with controls. The decline in the first session activities of infected mice was slower than the controls. Infected mice showed fewer stereotype movements with maximum reduction in week 16 of infection. There was no correlation between mice ambulatory activities or stereotype movements and infection duration. The importance of these findings in relation to the course of the disease and the underlying mechanism(s) are discussed.