Prisoners of the forgotten plague.

This documentary looks at sleepy sickness (encephalitis lethargica), a disease which left thousands of people motionless and speechless in the 1920s. Virologist John Oxford worries that encephalitis lethargica was caused by a virus and that it might one day return - a fact which is illustrated by the story of 23-year-old Becky Howells who nearly died because with the disease in September 1993. Neurologist Stavia Blunt treated Becky and says she has seen a case a year since. She worries that there may be numerous cases a year which are perhaps misdiagnosed. The programme includes much archive footage from the 1920s and Jean Price, the sister of Philip Leather who was hospitalised with the disease aged 13 and is now an old man, tells his story. Oliver Sacks tells of his famous 'awakening' of a group of sleepy sickness patients in the 1960s. John Oxford examines samples from patients who had the flu decades ago to see if they are flu-based in origin.