Effects of stress or infection on rat behavior show robust reversals due to environmental disturbance

Abstract

Background: The behavior of animals is intricately linked to the environment; a relationship that is often studied in laboratory conditions by using environmental perturbations to study biological mechanisms underlying the behavioral change. Methods: This study pertains to two such well-studied and well-replicated perturbations, i.e., stress-induced anxiogenesis and Toxoplasma gondii -induced loss of innate fear. Here, we demonstrate that behavioral outcomes of these experimental manipulations are contingent upon the ambient quality of the wider environment where animal facilities are situated. Results: During late 2014 and early 2015, a building construction project started adjacent to our animal facility. During this phase, we observed that maternal separation stress caused anxiolysis, rather than historically observed anxiogenesis, in laboratory rats. We also found that Toxoplasma gondii infection caused an increase, rather than historically observed decrease, in innate aversion to predator odors in rats. Conclusion: These observations suggest that effects of stress and Toxoplasma gondii are dependent on variables in the environment that often go unreported in the published literature.

Latent toxoplasmosis and olfactory functions of Rh positive and Rh negative subjects

“…It is high for a medium concentration of urine but low for very low and for very high concentrations of urine. Moreover, recently published results showed that the direction and size of the effect of toxoplasmosis on pleasantness of the cat urine smell could depend on some unknown environmental factor(s) [33]. It will be necessary to include several concentrations of cat urine into future studies and examine in detail the effects of sex-toxoplasmosis-concentration interaction.…”