| lack of evidence for wild poliovirus circulation--united states, 1993. | following the isolation of wild poliovirus type 3 during january-february 1993 among members of a religious community objecting to vaccination in alberta, canada, surveillance for poliomyelitis was enhanced among related communities in the united states (1). in addition, during may-july 1993, a series of surveys was conducted in seven states (iowa, missouri, new york, ohio, pennsylvania, washington, and wisconsin) to determine whether wild poliovirus was circulating or had circulated recently am ... | 1995 | 7799910 |