The evolving epidemiology of chlamydial and gonococcal infections in response to control programs in Winnipeg, Canada

Objectives. The purpose of this study was to describe and compare the transmission dynamics of chlamydia and gonorrhea in Winnipeg, Manitoba, Canada, and to assess implications for control programs. Methods. Chlamydia and gonorrhea surveillance case reports (1988 through 1995) and contact- tracing reports (1991 through 1995) were examined. Results. High incidence rates of both chlamydia and gonorrhea clustered in geographic core areas characterized by low socioeconomic status. A decline in the number of reported cases of chlamydia (61%) and gonorrhea (64%) occurred between 1988 and 1995. For chlamydia, the decline was most prominent in non-core area cases, while for gonorrhea it was similar in core and noncore areas. Conclusions. Chlamydia and gonorrhea appear to be evolving through different epidemic phases, with chlamydia transmission, in response to a newly introduced control program, becoming more core dependent and gonorrhea transmission becoming more sporadic in the face of a sustained control effort. Focused control programs, based on an understanding of the transmission dynamics of chlamydia and gonorrhea, may make their elimination a feasible goal.