Chancroid in the United States, 1981-1990: evidence for underreporting of cases.

Chancroid, a bacterial sexually transmitted disease (STD) characterized by genital ulceration, has reemerged in the United States during the last decade. From 1950 to 1980, cases were infrequently reported. After an epidemic in California in 1981, however, the numbers of cases increased, peaking in 1987 at 5,035. Despite a subsequent decline in numbers of reported cases to 4,223 in 1990, new areas continue to report outbreaks. Interpreting chancroid surveillance data is difficult because confirmatory culture media are not commercially available. In addition, states may not require that unconfirmed or even confirmed cases be reported. To determine if chancroid is more widely distributed than surveillance figures indicate, CDC contacted STD clinics in 115 health departments, located in 32 states, the District of Columbia, and Puerto Rico--areas chosen because they had reported five or more cases of chancroid in any single year during 1986-1990--to determine if cases might be occurring but not reported. Only 16 of the 115 clinics had culture media available for Haemophilus ducreyi, and only nine had laboratory facilities complete enough to definitively diagnose chancroid, syphilis, or genital herpes, the most common STDs characterized by genital ulcers. Five or more clinically likely cases occurring in 1990 were identified in 24 states, seven more than surveillance figures indicated. Surveillance can be improved if a) states utilize the definitions for chancroid cases adopted for use in 1990 and b) microbiology laboratories utilize enhanced diagnostic methods.