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Chronic Toxoplasma infections and familiarity-novelty discrimination in the mouse
Abstract:
Male mice were exposed to a black arm and the stem of a Y-maze; entrance to a white arm was blocked by a transparent door. Toxoplasma-infected mice were significantly less active and tended to produce fewer faecal boluses than uninfected controls. In a subsequent free-choice trial, in which both arms were black, the uninfected mice spent significantly more time in the novel (previously blocked) arm; the infected mice showed no preference for either choice arm. Possible explanations are discussed. In particular, it seems that Toxoplasma-infected mice may be less responsive to novel stimuli. This suggestion has important implications for our understanding of one of the major ways in which Toxoplasma passes from host to host. If Toxoplasma infections impair responsiveness to novel stimuli, then infected mice are more likely to be taken by predators.
Insights
Toxoplasma infection reduces mouse activity and responsiveness to new environments. Infected mice showed no preference in a Y-maze, unlike uninfected mice, suggesting impaired predator detection.
Area of Science:
- Behavioral neuroscience
- Infectious disease research
- Parasitology
Background:
- Toxoplasma gondii is a parasite with a complex life cycle involving rodents and felines.
- Altered host behavior is a known effect of Toxoplasma infection, potentially facilitating transmission.
Purpose of the Study:
- To investigate the effect of Toxoplasma infection on mouse behavior, specifically activity levels and response to novel stimuli.
- To assess how Toxoplasma-induced behavioral changes might influence predator-prey dynamics.
Main Methods:
- Male mice were infected with Toxoplasma gondii.
- Behavioral tests were conducted using a Y-maze with varying arm colors and accessibility.
- Activity levels and choice preferences in a novel environment were recorded and compared between infected and uninfected mice.
Main Results:
- Toxoplasma-infected mice exhibited significantly reduced activity and fewer fecal boli compared to controls.
- In a Y-maze test with novel stimuli, uninfected mice preferred the previously blocked arm, while infected mice showed no preference.
- Infected mice appeared less responsive to novel environmental cues.
Conclusions:
- Toxoplasma infection significantly alters mouse behavior, reducing activity and diminishing responses to novelty.
- These behavioral changes in infected mice may decrease their awareness of predators, increasing the likelihood of predation and parasite transmission.
- The findings highlight the impact of Toxoplasma on host behavior and its ecological implications for parasite transmission.