FIG. 1.

Course of lesion development in BALB/c mice infected with L. major (circles) or with both L. major and T. gondii (squares). The animals were infected intraperitoneally with 20 cysts of the ME-49 strain derived from the brains of C57BL/6 mice chronically infected with T. gondii and challenged in the hind footpads with 10⁶ stationary forms of the WHO MHOM/80/Friedlin strain of L. major during acute (A) or chronic (B) toxoplasmosis. (C) Mice were previously infected with L. major and, after 14 days, were challenged with T. gondii. The animals in the different experiments were monitored for 7 weeks, except for animals infected with T. gondii 5 days prior to infection with L. major, which were monitored for 16 weeks (A). The insert in panel A shows a curve of footpad swelling of resistant C57BL/6 mice infected with 10⁶ stationary forms of L. major. Each point represents the mean (± standard deviation) lesion size for 10 mice. Asterisks indicate that differences are statistically significant (P < 0.05), as evaluated by Students’ t test. Results from one representative experiment of two separately performed are shown.