From the early 1920s until the advent of penicillin in the mid 1940s, a clinical course of
malaria was the only effective treatment of general paresis, a common manifestation of
tertiary syphilis that was nearly always fatal. For a number of reasons, Plasmodium vivax
became the parasite species most often employed for what became known as
malariotherapy. This provided an opportunity, probably unique in the annals of medicine, to
observe and investigate the biology, immunology and clinical evolution of a dangerous …