Imported leprosy in the United States, 1978 through 1988: An epidemic without secondary transmission

Objectives. Leprosy remains a major health problem in many regions of the world. In the United States, although leprosy continues to be reported, approximately 90% of cases are imported (i.e., occur among immigrants and refugees). An increase in imported cases began in 1978. This study was conducted to analyze this trend and to characterize the contributing cases. Methods. Centers for Disease Control leprosy surveillance data from 1971 through 1988 were analyzed. Results. The number of imported cases reported annually was relatively constant from 1971 through 1977 (mean = 119 per year), increased to 307 in 1985, and then decreased to 102 in 1988. Of the 957 excess cases reported from 1978 through 1988, 73.4% were among persons from Southeast Asia, including 51.3% from Vietnam, Cambodia, and Laos (Indochina). There was no coincident increase in indigenous cases of leprosy; the mean annual number of such cases was 17.7 (range = 10 to 29). Leprosy remains endemic in Texas, Hawaii, Louisiana, and possibly California. Conclusions. An epidemic of imported leprosy began in the United States in 1978, peaked in 1985, and ended by 1988. This increase was primarily due to cases among refugees from Indochina and was limited by a decrease in the influx of Indochinese refugees in the mid-1980s. There is no evidence that these cases resulted in transmission in the United States.