Concurrent infections ofTrichinella spiralis andToxoplasma gondii in mice

Concurrent infections with two parasites: a nematode,Trichinella spiralis, and a protozoon,Toxoplasma gondii, were investigated. Antibody production (total immunoglobulin and IgM) was similar in double and single infections. However, the number ofToxoplasma cysts in the brains of mice infected withTrichinella and challenged 1–6 weeks later withToxoplasma was higher than in mice infected withToxoplasma alone, while mice infected withToxoplasma and challenged 4–14 days later withTrichinella had lower worm burdens in the intestine than animals infected withTrichinella alone. Greater loss in body weight was observed in mice infected with both parasites than in those infected with either parasite alone.