Temporal and geographic patterns of isolates of nonpolio enterovirus in the United States, 1970-1983.

Surveillance data on nonpolio enterovirus (NPEV) from the Centers for Disease Control (Atlanta, Georgia) for the United States from 1970 to 1983 were analyzed for the temporal and geographic patterns of the most common types of NPEV isolated. The number of isolates varied from year to year, partly because of variation in the number of reporting laboratories and partly because of true variation in the rate of isolation. The most common types isolated also varied from year to year, yet the 15 most common types over the entire 14-year period accounted for 65%-89% of isolates for a given year. The 15 most common types of NPEV had two basic patterns of isolation, one in which a type had periodic epidemic years and the other in which it did not. In 11 of the 14 years there was one or more epidemic types, each accounting for greater than or equal to 20% of all isolates of NPEV that year. The six most common isolates in March, April, and May predicted an average of 59% of the total isolates detected in July-December of that year.