The effect of congenital Toxoplasma infection on mouse activity and relative preference for exposed areas over a series of trials.

Previous studies showed that mice with congenital Toxoplasma infections tend to be much more active and tend to show a smaller relative preference for more exposed and novel areas than do uninfected controls. However, in those studies, mice were exposed to behavioural testing procedures once only. Results described here show that these differences (and differences defaecation) are more than just transitory phenomena observed on a first exposure to a novel area. The differences between infected and uninfected mice were clear during each of five separate trials; moreover, they tended to increase from the first to the fifth trial. The possible implications of these findings for the continuation of the life-cycle of the parasite in the environment are considered.