Spatial bridges for the importation of gonorrhea and chlamydial infection

An Investigation of Early Syphilis Among Men Who have Sex with Men: Alaska, 2018: Findings from a 2018 Rapid Ethnographic Assessment

The state of Alaska had a sharp increase in cases of primary and secondary syphilis among gay, bisexual, and other men who have sex with men (GBMSM) in 2018, centered in Anchorage. A rapid ethnographic assessment was conducted in October 2018 to examine contextual factors contributing to local increases in syphilis. The assessment team conducted qualitative interviews with 64 (N=49 interviews) key informants in Anchorage and Matanuska-Susitna Valley identified through the STD/HIV program at the Alaska Department of Health and Social Services, Division of Public Health (ADPH):  ADPH staff (n = 11; 22%) Medical Providers (n = 18; 37%), Community-Based Organizations/Partners (n = 9; 18%), and GBMSM Community Members (n = 11; 22%). This project was deemed exempt from IRB review. Primary factors affecting syphilis transmission, care, and treatment among GBMSM were: (1) Low awareness about the current syphilis outbreak and ambivalence about syphilis and other STIs; (2) Aspects of sexual partnering such as travel, tourism, and the use of online sites and apps to facilitate anonymous sex and multiple (both sequential/concurrent) partnering; (3) The synergistic effects of substance use, homelessness, and transactional sex; (4) Choosing condomless sex; and (5) Challenges accessing healthcare, including the ability to find appropriate and culturally competent care. Syphilis increases may have been influenced by factors which spanned multiple sectors of the Anchorage community, including individual behavior, community-level risk and protective factors, and use of and interactions with resources offered by ADPH, community-based organizations, and medical providers.

Structural bridging network position is associated with HIV status in a younger Black men who have sex with men epidemic

Younger Black men who have sex with men (BMSM) ages 16-29 have the highest rates of HIV in the United States. Despite increased attention to social and sexual networks as a framework for biomedical intervention, the role of measured network positions, such as bridging and their relationship to HIV risk has received limited attention. A network sample (N = 620) of BMSM respondents (N = 154) and their MSM and transgendered person network members (N = 466) was generated through respondent driven sampling of BMSM and elicitation of their personal networks. Bridging status of each network member was determined by a constraint measure and was used to assess the relationship between this bridging and unprotected anal intercourse (UAI), sex-drug use (SDU), group sex (GS) and HIV status within the network in South Chicago. Low, moderate and high bridging was observed in 411 (66.8 %), 81 (13.2 %) and 123 (20.0 %) of the network. In addition to age and having sex with men only, moderate and high levels of bridging were associated with HIV status (aOR 3.19; 95 % CI 1.58-6.45 and aOR 3.83; 95 % CI 1.23-11.95, respectively). Risk behaviors observed including UAS, GS, and SDU were not associated with HIV status, however, they clustered together in their associations with one another. Bridging network position but not risk behavior was associated with HIV status in this network sample of younger BMSM. Socio-structural features such as position within the network may be important when implementing effective HIV prevention interventions in younger BMSM populations.

Sexual networks, surveillance, and geographical space during syphilis outbreaks in rural North Carolina

BACKGROUND

Sexually transmitted infections (STIs) spread along sexual networks whose structural characteristics promote transmission that routine surveillance may not capture. Cases who have partners from multiple localities may operate as spatial network bridges, thereby facilitating geographical dissemination. We investigated how surveillance, sexual networks, and spatial bridges relate to each other for syphilis outbreaks in rural counties of North Carolina.

METHODS

We selected from the state health department's surveillance database cases diagnosed with primary, secondary, or early latent syphilis during October 1998 to December 2002 and who resided in central and southeastern North Carolina, along with their sex partners and their social contacts irrespective of infection status. We applied matching algorithms to eliminate duplicate names and create a unique roster of partnerships from which networks were compiled and graphed. Network members were differentiated by disease status and county of residence.

RESULTS

In the county most affected by the outbreak, densely connected networks indicative of STI outbreaks were consistent with increased incidence and a large case load. In other counties, the case loads were low with fluctuating incidence, but network structures suggested the presence of outbreaks. In a county with stable, low incidence and a high number of cases, the networks were sparse and dendritic, indicative of endemic spread. Outbreak counties exhibited densely connected networks within well-defined geographic boundaries and low connectivity between counties; spatial bridges did not seem to facilitate transmission.

CONCLUSIONS

Simple visualization of sexual networks can provide key information to identify communities most in need of resources for outbreak investigation and disease control.

Predictors of high chlamydia and gonorrhea positivity rates among men in the southern United States

BACKGROUND

Routine screening for Chlamydia trachomatis and Neisseria gonorrhoeae in men in the United States is not recommended. However, untreated men remain a potential reservoir for chlamydial and gonococcal infections and reinfection among women. Chlamydia and gonorrhea positivities and associated epidemiology were evaluated among males in the southern United States.

METHODS

Data were analyzed from 603320 males, aged 15 to 60 years, who were undergoing chlamydia and gonorrhea testing in sexually transmitted disease, family planning, correctional, college, and other facilities between 2001 and 2005.

RESULTS

Males screened were primarily non-Hispanic black (63%) or non-Hispanic white (37%). Overall, chlamydia and gonorrhea positivities were both 13%. From 2001 to 2005, the chlamydia positivity increased 32% and the gonorrhea positivity decreased 28%. With increasing age, chlamydia positivity decreased, while gonorrhea positivity remained relatively stable. However, in men aged less than 30 years, both chlamydia and gonorrhea positivities were significantly higher than in men aged 30 years or greater (P < .01). Non-Hispanic blacks had a 5-fold higher risk for gonorrhea and 1.5-fold higher risk for chlamydia than non-Hispanic whites (P < .001). Men living in metropolitan statistical areas had a 1.27-fold higher risk for gonorrhea than men living in non-metropolitan statistical areas (P <.001).

CONCLUSIONS

Chlamydia and gonorrhea positivity rates were high in males in the southern United States relative to the rates among men in the United States and were influenced by demographic and geographic factors.

Prevalence trends in Sweden for the new variant of Chlamydia trachomatis

In 2006, a new variant of Chlamydia trachomatis (nvCT) was discovered in Sweden that was not detectable with Abbott m2000 (Abbott) and Amplicor/COBAS Amplicor/TaqMan48 (Roche). The proportion of nvCT was 20-64% of the detected Chlamydia cases in counties using Abbott/Roche test systems. Although the ProbeTec system from Becton Dickinson (BD) could detect nvCT, the proportion of nvCT in counties using BD was 7-19%. The objective of the current study was to follow the nvCT proportions from 2007 to 2009 in two counties that used Roche and had introduced test systems able to detect nvCT in late 2006. The nvCT was also followed in two counties that used BD, and in all four counties the effect of nvCT on the serotype distribution of C. trachomatis wild-type strains was analysed. A total of 2576 specimens positive for C. trachomatis were collected in the four counties at three time points, and analysed for nvCT and serotype E. The proportion of nvCT declined significantly in the two counties using Roche, from 65% and 48% in 2007 to 24% for both counties in 2009 (p <0.001). The nvCT proportion increased in Norrbotten county, which used BD, from 9% in 2007 to 19% in 2009 (p 0.03). In Uppsala county, which also used BD but was surrounded by counties using detection systems from Roche, the proportion of nvCT declined from 24% in 2007 to 18% in 2009 (p <0.03). No major difference in the level of serotype E was seen. The proportion of nvCT seems to rapidly converge in the Swedish counties after the selective diagnostic advantage for nvCT has been lost in the Abbott/Roche counties.

Sexual networks are diverse and complex: prevalence of relationships bridging population subgroups in the Seattle Sex Survey

GOAL

To better understand how and how often individuals bridge demographic groups in their sex partnerships, and to describe the epidemiologic characteristics of bridging and associations with history of sexually transmitted infection (STI).

METHODS

We describe the frequency of different hypothetical sexual bridging types among men and women aged 18 to 39 participating in a random digit dialing survey conducted in 2003 to 2004, and the associations of bridging behavior with risk factors for and self-reported history of STI.

RESULTS

Of the 1013 participants who described their 2 most recent sexual partnerships, 753 (74%), were classified as a bridge of some type. Education bridges were most prevalent (46%), followed by spatial (34%), age (29%), race (24%), and gender bridges (3%).

CONCLUSIONS

Sexual networks are diverse and complex, and there are multiple potential paths for infection flow.

Social determinants and sexually transmitted disease disparities

Social determinants of health play an important role in sexually transmitted disease (STD) transmission and acquisition; consequently, racial and ethnic disparities among social determinants are influences upon disparities in STD rates. In this narrative review, we outline a general model showing the relationship between social determinants and STD outcomes, mediated by epidemiologic context. We then review 4 specific social determinants relevant to STD disparities: segregation, health care, socioeconomics and correctional experiences, followed by 2 facets of the resultant epidemiologic context: core areas and sexual networks. This review shows that disparities exist among the social determinants and that they are related to each other, as well as to core areas, sexual networks, and STD rates. Finally, we discuss the implications of our review for STD prevention and control with particular attention to STD program collaboration and service integration.

Partner age difference and prevalence of chlamydial infection among young adult women

OBJECTIVES

Sexual partner mixing by age is common among adolescents and adults. Although adolescent girls with older male partners are at increased risk of sexually transmitted infection, the importance of this association in young adults is unclear.

GOAL

To assess the association between partner age difference and prevalence of chlamydial infection among young women.

STUDY DESIGN

Using Wave III of the National Longitudinal Study of Adolescent Health (April 2, 2001-May 9, 2002), the authors examined the relation between the prevalence of chlamydial infection and the partner age among women aged 18 to 26 years.

RESULTS

Among women with most recent partners 2 to 8 years younger, the odds of chlamydial infection were approximately 2 times greater [adjusted odds ratio (OR), 1.8; 95% confidence interval (CI), 0.9, 3.5] than among women with partners within 1-year age difference, adjusting for number of partners in the past year. Prevalence of chlamydial infection was only slightly greater for women with partners 2 to 5 years older (adjusted OR, 1.4; 95% CI, 0.9, 2.3) and partners 6 or more years older (adjusted OR, 1.6; 95% CI, 0.9, 2.8), when compared with women with partners within 1-year age difference. The relation between most discordant partner age difference and chlamydial infection seems to vary by women's race/ethnicity, although these stratified estimates are imprecise.

CONCLUSIONS

These findings suggest that among young adult women, in contrast to adolescents, older male partners are only moderately associated with the prevalence of chlamydial infection. Young adult women have the lowest odds of infection with partners within 1 year of age difference.

Sexually transmitted diseases in the USA: temporal trends

This paper reviews the temporal trends in sexually transmitted diseases (STDs) and discusses the factors affecting the epidemiology of bacterial STDs.

Early Syphilis Among Men in Connecticut: Epidemiologic and Spatial Patterns

OBJECTIVE

The objective of this study was to describe the epidemiology of early syphilis among men in Connecticut, a moderate-prevalence region, in 2004.

STUDY DESIGN

The authors conducted a cross-sectional analysis of health department data.

RESULTS

Fifty-five cases were reported from 25 different towns. A majority of cases (82%) were reported among men who have sex with men, and 22% reported coinfection with HIV. Spatial analysis indicated moderate clustering of cases. Approximately half of 197 reported sex partners were not from Connecticut, including 28% from New York City and 20% from other states/countries. The median distance between partners was 48 km (30 miles). Twenty-three percent of syphilis cases had both local and nonlocal partners.

CONCLUSIONS

The current epidemiology of early syphilis in Connecticut is consistent with national trends. However, the dispersal of cases throughout the state and the high proportion of reported sex partners residing outside of Connecticut suggest that this state is not a core area of endemic transmission.

Spatial bridges and the spread of Chlamydia: the case of a county in Sweden

OBJECTIVES

The so-called small-world effect can have a great impact on efforts to control the incidence and prevalence of sexually transmitted infections. This is because a small number of so-called spatial bridgers (individuals who, through sexual contacts, interconnect geographically distant areas) can drastically lower the average path length in the sexual network and, as a result, make locally based intervention programs much less effective. The objectives of this study were to analyze the sociodemographic characteristics of these bridgers and to compare the result with the remaining study population. The purpose was to determine whether it is possible to identify them for targeted intervention programs.

STUDY DESIGN

During 2001, contact tracing was performed in approximately 98% of all cases with positive test results in Värmland County. The sexual networks obtained constituted a study population of 851 individuals. Statistical analysis was used to characterize individuals engaged in spatial bridging behavior.

RESULTS

Approximately 8% of the study population was characterized as spatial bridgers. Using multivariate analysis, we found almost no significant differences between these individuals and the rest of the study population when it came to sociodemographic variables, including education, economy, and ethnicity.

CONCLUSION

The number of spatial bridgers is high enough to create a small-world network with links that can fuel the endemic chlamydia in Värmland County. Sociodemographic information could not be used to characterize spatial bridgers. In interventions against chlamydia, spatial bridgers shall be considered as potentially important for sustaining the disease.

Gonorrhea Reinfection Among Sexually Transmitted Disease Clinic Attendees in Baltimore, Maryland

OBJECTIVES

We hypothesized that an active follow-up program to assess for reinfection after gonorrhea treatment could be a useful disease control strategy.

GOAL

We evaluated an active follow-up and repeat testing program for all Baltimore sexually transmitted disease clinic patients diagnosed with gonorrhea.

STUDY DESIGN

From September 2003 to May 2004, all clients with a treated gonorrhea infection were advised to return 3 months later for repeat testing. If clients did not return as scheduled, field outreach was attempted. At follow-up visits, urine was tested for gonorrhea and consenting participants completed a behavioral survey. In addition, we reviewed morbidity records for any intercurrent gonorrhea infections reported during the project period.

RESULTS

Of the 667 participants diagnosed with gonorrhea at baseline, 54 had a gonorrhea reinfection diagnosed for an incidence of 13.8 per 100 person-years. One hundred seventy-eight (27%) either presented for a follow-up visit or were located through field efforts, and of these, 5 (2.8%) had gonorrhea detected on follow-up urine testing. No measured factors had predictive value in identifying gonorrhea reinfection.

CONCLUSIONS

Although reinfection rates were high, we found that field staff intervention to increase follow-up testing rates did not identify a significant amount of repeat infections compared with passive surveillance.

Spatial bridging in a network of drug-using male sex workers

This study sought to determine whether drug-using male sex workers (MSWs) spatially bridge sexual networks across cities and to determine whether the behaviors of MSWs who bridge differ from the behaviors of those who do not. Data were collected from 42 MSWs in Houston, Texas, between May 2003 and February 2004. Spatial bridging was defined as having traded sex for money in another city before traveling to and trading in Houston. Cities bridged by MSWs were geographically plotted and were primarily located in the Gulf Coast and in Florida. Slightly less than half of MSWs were identified as spatially bridging from one city to another. A significantly higher proportion of MSWs who bridged cities were homosexual (55% vs. 23%) and HIV positive (31% vs. 5%). Those who bridged cities used marijuana and injected drugs more frequently and had significantly more male sex partners than MSWs who did not bridge cities. Despite the small sample size, this study found that many drug-using MSWs spatially bridge sexual networks in cities where they trade sex for money.