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Chancroid Follow-Up--California

In May 1981, 71 (92%) of 77 patients who presented to the Orange County (California) Special Diseases Clinic with genital ulcers had negative darkfield examinations, compared with 135 (69%) of 197 patients during the preceding 4 months. Haemophilus ducreyi was isolated from 30 patients with similar lesions in December 1981. Since then, 271 cultures from genital lesions in over 1,000 people have grown H. ducreyi, with the peak number occurring during January 1982 (Figure 3).

Although the CDC-recommended treatment regimen of erythromycin or sulfamethoxazole/trimethoprim had been uniformly used since January 1982, culture-confirmed chancroid cases continued to average 34 per month between December 1981 and June 1982. In an effort to reduce this number, more aggressive, nontraditional control measures were adopted in March 1982. These included offering prophylactic therapy to 287 women identified as prostitutes in the county jail, in addition to those who voluntarily requested an examination at the clinic. Prophylactic therapy was also offered to over 700 clinic patients who reported recent sexual contact with "door-to-door" prostitutes. By July, the number of positive cultures had dropped to 14; in August, 10 were reported. Thereafter, the monthly number of cases continued to decline, and only one culture-proven case has been reported in 1983, despite continued, active surveillance.

The profile of chancroid patients has remained consistent throughout this outbreak. Ninety-six percent of the culture-proven cases occurred among Hispanic males, at least 86% of whom had recent sexual contact with prostitutes. One hundred forty-two of the 271 patients offered descriptions of prostitutes to whom they had been exposed; 98 (69%) of these referred to women who solicited from door-to-door.

There were five known prostitutes among the 271 culture-proven chancroid patients. Two additional prostitutes from that area who had no chancroid symptoms were originally reported as having had H. ducreyi recovered from cervical specimens (1). However, subsequent microbiologic studies showed that these specimens were not H. ducreyi, but another species of Haemophilus. Simultaneous infection with H. ducreyi and Treponema pallidum was documented for 15 patients. In one patient, herpes simplex virus was cultured along with H. ducreyi.

Thirty-seven of the 41 H. ducreyi isolates examined between December 1981 and February 1983 shared a similar antibiogram and contained a common 3.2 megadalton plasmid, coding for B-lactamase production. This plasmid is identical to the gonococcal plasmid and is similar to one identified in a strain of H. ducreyi that has been epidemiologically linked to a chancroid case in Brazil (2). Over 200 B-lactamase-producing H. ducreyi strains from other geographic areas have been shown not to contain this particular plasmid. Reported by JR Greenwood, PhD, TJ Prendergast, MD, LR Ehling, MD, Orange County Health Dept, C Zavala, J Chin, MD, State Epidemiologist, California Dept of Health Svcs; Sexually Transmitted Diseases Laboratory Program, Center for Infectious Diseases, Field Svcs Div, Epidemiology Program Office, Div of Venereal Disease Control, Center for Prevention Svcs, CDC.

Editorial Note

Editorial Note: In 1982, Orange County, California, reported 240 cases of culture-confirmed chancroid, over seven times the number reported by all of California the previous year. Initial efforts to control this outbreak by treating patients and their sexual partners with recommended regimens were unsuccessful. The eventual success of the control program was attributed to the policy of offering prophylactic therapy to certain high-risk groups whose members were either asymptomatic or had genital ulcers with no definitive diagnosis. These groups included: 1) prostitutes in the county jail, 2) clinic patients reporting prostitute contact, and 3) clinic patients with darkfield-negative genital ulcers. Continued surveillance and therapeutic action will be necessary if chancroid is to remain controlled.


  1. CDC. Chancroid--California. MMWR 1982;31(14):173-5.

  2. Handsfield HH, Totten PA, Fennel CL, Falkow S, Holmes KK. Molecular epidemiology of Haemophilus ducreyi infections. Ann Intern Med 1981;95(3):315-8.

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