In addition, the number of T. gondii cysts in the brains of the survivors was enumerated after 1 mo PI, and CCR5−/− mice had a 5-fold higher cyst number (2,563 ± 350) than control wild-type mice (538 ± 155) (p = 0.002) (unpublished data). The gene discussed is CCR5; the disease is cyst.