Background: Estimates of the duration of untreated genital infections with Chlamydia trachomatis vary. Accurately estimating the distribution of the duration of infection would be useful in the counseling patients, and is essential when modeling the burden of chlamydial disease and the potential impact of prevention programs.
Goal: The authors review the scientific literature to summarize what is known about the duration of genital chlamydial infection and the factors that affect it.
Study design: Literature review of animal and human studies.
Results: Animal studies document a longer duration of infection in primates than in mice or guinea pigs. Although animals spontaneously become culture negative over time, numerous studies document persistent nonculture evidence of chlamydiae in the upper genital tract. Studies in which women have been serially cultured suggest that most untreated infections remain culture positive for more than 60 days. Small series report that some infections may persist for years. Most infections eventually become culture negative; however, non-culture evidence of chlamydiae often persist in women with negative cultures. The duration of chlamydial infection is reduced in animals previously exposed to chlamydiae and in older humans, suggesting that partial immunity may result from exposure. Data are inadequate to define the median duration of untreated infection or to derive a curve that describes the natural history of untreated genital chlamydial infections.
Conclusion: Current data do not allow one to reliably estimate the duration of genital infections with C trachomatis. Systematic retesting could help to better define the duration of infection in patients who, against medical advice, delay treatment for genital chlamydial infections.