Importation of Shiga bacillus dysentery into California. Clinical and public health significance.

Concurrent with the regional epidemic of classic Shiga dysentery in Central America during 1969 and 1970, a pronounced increase in the isolation of Shigella dysenteriae type 1 was noted in California. A retrospective study of 20 cases diagnosed in California in 1969 and 1970 revealed that 18 of the patients had traveled to Central America or Mexico during or immediately before the onset of symptoms. Sixteen were known to have been admitted to hospital; there was one death. Despite the concern that such importations might result in epidemics in this country among groups living in crowded, unsanitary settings, no definite secondary transmission was identified in this study. The problems of differential diagnosis, laboratory isolation of the agent, chemotherapy, and epidemic control are discussed.