California Gonorrhea Surveillance System: methodologic aspects and key results of a sample-based system.

Gonorrhea (GC) is a sexually transmitted infection caused by Neisseria gonorrhoeae and can cause a range of sequelae, including pelvic inflammatory disease, ectopic pregnancy and infertility among women, and epididymitis among men.1 Further, people infected with GC are more likely to acquire and transmit human immunodeficiency virus (HIV).2 After chlamydia, GC is the most commonly reported communicable disease in the U.S. and California.3 In 2006, 358,336 cases of GC were reported in the U.S., and 33,776 were reported in California.4 A key aspect of the epidemiology of GC is significant racial disparity, greater than for any other condition with a Healthy People 2010 objective.5 In California, the overall rate of GC infection in 2006 was 10.2 times higher among African Americans than among non-Hispanic whites, with more extreme disparities in some subpopulations.4 For example, among males aged 15 to 19 years, the rate among African Americans was 25.1 times higher than the rate for non-Hispanic whites. Similar disparities have been documented nationally.6 After several decades of steadily declining rates of GC in California, rates began increasing in 1999 and continued increasing through at least 2005 in all demographic subgroups (e.g., gender, race/ethnicity, age group, and geographic region).7 While the California Department of Public Health's (CDPH's) standard confidential morbidity report (CMR) surveillance system, structured on passive reporting from medical providers and laboratories, does include these demographic characteristics, it does not include risk factor data or detailed clinical data. Therefore, because of the large and increasing burden of GC, the profound racial disparities (a state and national priority target for action), and the need for more detailed risk and clinical data to identify factors associated with transmission, CDPH began work on a pilot system of expanded GC surveillance in one California health jurisdiction. This was a collaborative effort with the Centers for Disease Control and Prevention's (CDC's) Outcome Assessment through Systems of Integrated Surveillance (OASIS) workgroup enhanced GC surveillance project.8 This OASIS project included six other sites engaged in improving GC surveillance and, in particular, in collecting risk factor and clinical data for disease control and prevention. In many of these sites, the absolute number of GC cases was far too large to conduct interviews of all case subjects, given existing funding and staffing levels. Therefore, most OASIS project areas chose to focus on interviewing case subjects sampled from sexually transmitted disease (STD) clinics. In California, only 15% of GC cases are identified in STD clinics. Thus, we wanted to capture a representative sample of all cases, and not limit our enhanced GC surveillance efforts to STD clinics. Other approaches to enhanced GC surveillance, including provider-interview-based systems, have been explored successfully,9 but do not provide the level of risk data we felt was required for program development. During the second pilot phase of this enhanced GC surveillance system, conducted from 2004 to 2005, we expanded participation to include seven geographically distributed counties in California. In this article, we report on the final phase, the California Gonorrhea Surveillance System (CGSS), an enhanced surveillance system based on the previous model but developed independently by California in 2006 and fully implemented in all 61 local health jurisdictions (LHJs) by January 2007.