Effect of nesting material on body weights of mice infected with Toxoplasma gondii.

Toxoplasmosis, a disease caused by the parasitic protozoan Toxoplasma gondii, can cause a number of clinical signs in mice, including weight loss. This weight loss likely is related to the host immune response and is important to monitor in Toxoplasma studies. Several studies have demonstrated that nesting material can affect body weights of mice. We therefore sought to assess the effects of nesting material on body weights of mice infected with Toxoplasma. We housed mice with or without nesting material and weighed and clinically assessed them twice weekly for 30 days prior to and 5 wk after Toxoplasma inoculation. Nesting material did not significantly alter the weights of mice after Toxoplasma inoculation but did decrease rates of growth prior to inoculation. Nesting material did not affect the clinical outcome of Toxoplasma infections, supporting the provision of nesting material in mouse Toxoplasma experiments.