Abstract
An observational study using video recordings and computer assisted data analysis showed that infection with Toxocara canis larvae had a marked effect on five readily and reliably differentiable categories of murine behaviour. The infection was also associated with an increase in the number of shorter bouts of each behaviour. These results indicate that infection with T. canis renders mice hyperactive, and would appear to justify a complete reappraisal of the role of this neurotropic parasite as a cause of behavioural abnormalities such as hyperactivity in children.