Invisible armies examines infectious diseases and how they have been carried around the world as cultures come into contact with each other, and also how some previously eliminated diseases, such as measles and TB, are making a comeback in the western world because of carelessness about immunisation programs. Diseases discussed include syphilis, malaria and smallpox. “Will we ever learn?” Never before have we had such powerful weapons against disease but the tendency to depend on them too much has led to a philosophy of cure rather than prevention. The program looks at AIDS, syphilis and diseases associated with tobacco use and salt. Norman Swan wrote and narrates this thought provoking series, which contends that the real causes of epidemics are social forces.