Geographic Bridges for Importation of STD in the Seattle Metropolitan Area: Barbarians at the Gates Roxanne P. Kerani, Matthew R. Golden, William L.H. Whittington, Hunter H. Handsfield, King K. Holmes

Background Bridges serve as links for subpopulations with differing prevalances of STD Geographic bridges may import STD from high to low prevalence regions Few studies have examined travel and STDs other than HIV

Objectives To describe geographic bridges residing in the Seattle Metropolitan Area (SMA) To compare attributes of partnerships involving partners residing in and outside of the SMA

Methods Data collected as part of a study of expedited partner treatment Study period: Oct, 1998 – Jan, 2002 Population: Residents of King Co., WA –Heterosexual –14+ years –Diagnosed & reported with gonorrhea or chlamydia –Contacted within 14 days of treatment

Methods Exclusions: –Current incarceration –No provider consent for contact –No sex partners (SP) in previous 60 days –Persons with unknown residence N = 3,123 Interviews included questions regarding up to nine SPs in previous 60 days

Bridgers Participants with partners residing both in (local) and outside (distant) the SMA

Methods Analyses of individuals: –Bivariate: T-tests and chi-squares –Multivariate: Logistic regression Analyses of partnerships –Bivariate: GEE models

Study Population

Bridgers 310 (9.5%) of participants reported at least one distant partner 140 (4.9%) of participants reported both local and distant partners (bridgers)

Percent Bridgers Demographics & STD Dx

Education, Employment, and Residence

Number of Sex Partners

Concurrency and Reason for Visit

Multivariate Results

Results - Partnerships Partnerships among bridgers: N=329 Residence of partners: –53% SMA –14% Elsewhere in WA –33% Within the US, outside WA

Partner Type and Ability to Contact

Partner Knowledge of Infection and Perceived Future Sex with SP

Partnerships: Perceived Transmission Direction

Summary 5% of patients were geographic bridges Bridgers were more likely to be white, older, employed, and of higher SES, and to report more partners and concurrency Distant partnerships were more likely to represent casual relationships with little potential for future contact

Limitations Study sample not representative of all gonorrhea and chlamydia cases in King Co. Direction of transmission is unknown We don’t know where sex took place Anonymous partners may be underrepresented

Conclusions Factors associated with bridging are generally those associated with low rates of STD Bridges may be important in maintaining GC/CT endemicity in low prevalence populations Is business travel related to risky sex? Control of disease in some populations may require enhanced collaboration between distant public health agencies