Smallpox surveillance in Bangladesh: I - Development of surveillance containment strategy.

A major epidemic of Variola major with an estimated 90 000 cases and 18 000 deaths occurred in Bangladesh in 1972. During a 3-year period methods of active surveillance (market search, outbreak investigation, and house-to-house search) were developed to supplement the passive reporting system. The percentage of smallpox cases detected increased from 11.8% in 1972 to 83% in 1975. Together with the implementation of improved methods of outbreak control, smallpox transmission was interrupted in October 1975.