The Invisible enemy

A survey of the more important virus diseases and the efforts of WHO and other authorities to overcome them: foot and mouth disease; polio - why it is apparently a disease of advanced countries - and the Salk vaccine; yellow fever, and a question: “Can it be kept out of Asia?”; the difficulties of preventing influenza by vaccination; the importance of quarantine and other control measures at ports and airports. Narrated by James McKechnie.