Herpes simplex virus in clinically suspected chancroid in Nairobi, Kenya.

Of 110 males selected for review with possible chancroid, 96 were clinically diagnosed as having chancroid, 7 as having herpetic lesions, and 7 as having syphilis. Of the 96 patients diagnosed clinically as chancroid, 76 (79.2%) were culture positive for H. ducreyi. 9 (9.4%) of these 96 patients yielded Herpes Simplex Virus (HSV). Both HSV and H. ducreyi were isolated from 5 of the patients, and from 4 of the patients HSV alone was isolated. 7 patients (6.4%) were clinically diagnosed as having herpetic ulcers. 5 of these grew HSV. Overall, 14 of the 110 patients (12.7%) yielded HSV. 1 patient, who presented with small vesicular lesions characteristic of HSV, yielded the virus on culture. The vesicles were initially negative for H. ducreyi, but 6 days later he had developed deep purulent ulcers in the same sites as the vesicular lesions and became culture positive for H. ducreyi snd HSV-negative. The possible association between HSV and chancroid is discussed in the light of these findings and comparisons made between the results of the present study and earlier findings made in Kenya and elsewhere, with suggestions being given as to the reasons for the apparent differences. The HSV isolation techniques used in this study may be less sensitive than those used in other studies, but it is highly unlikely that this possibility alone accounts for all of the observed differences. Patients with hepetic ulcers may be less likely to present early in the course of the disease, if at all, believing the infection to be minor and one that will heal on its own. It is also possible that HSV infection is less common in Kenya, either alone or as an initiator of chancroid, than in the US or Europe, becuase of a higher rate of childhood HSV infections in Kenya, which may confer a degree of immunity against genital HSV infection in this population. The lower prevalence of HSV in association with H. ducreyi reported may be at least partly the result of a much higher incidence in Kenya of chancroid which is not initiated by HSV. A higher incidence of HSV genital infection in Europe and America would also make it more likely that HSV would fortuitously be isolated more frequently from H. ducreyi positive lesions.