A brief tool to assess capacity to consent for medical care among homeless individuals with problematic substance use: study protocol.

Background: Public health care increasingly uses outreach models to engage individuals who are marginalized, many of whom misuse substances. Problematic substance use, together with marginalization from the health care system, among homeless adults makes it difficult to assess their capacity to consent to medical care. Tools have been developed to assess capacity to consent; however, these tools are lengthy and unsuitable for outreach settings.

Chlamydia public health programs and the epidemiology of pelvic inflammatory disease and ectopic pregnancy.

Background: Many countries have witnessed a disturbing increase in cases of Chlamydia trachomatis infection despite enhanced control programs. Since the goal of Chlamydia control is to prevent reproductive complications such as pelvic inflammatory disease and ectopic pregnancy, an understanding of recent trends in these conditions is needed to fully evaluate the effect of control efforts.

Methods: We analyzed 2 provincial, comprehensive health services administrative databases (encompassing hospitalizations and all physician-delivered services) for pelvic inflammatory disease and ectopic pregnancy trends from 1992 through 2009 in women of reproductive age in British Columbia, Canada.

Towards targeted screening for acute HIV infections in British Columbia.

Background: Our objective was to describe the characteristics of acute and established HIV infections diagnosed in the Canadian province of British Columbia. Province-wide HIV testing and surveillance data were analyzed to inform recommendations for targeted use of screening algorithms to detect acute HIV infections.

Methods: Acute HIV infection was defined as a confirmed reactive HIV p24 antigen test (or HIV nucleic acid test), a non-reactive or reactive HIV EIA screening test and a non-reactive or indeterminate Western Blot.

Using centralized laboratory data to monitor trends in herpes simplex virus type 1 and 2 infection in British Columbia and the changing etiology of genital herpes.

Objectives: Understanding the regional epidemiology of genital Herpes Simplex Virus (HSV) infections is important for clinical and public health practice, due to the increasing availability of type-specific serologic testing in Canada and the contribution of genital HSV-2 infection to ongoing HIV transmission. We used centralized laboratory data to describe trends in viral identifications of genital HSV in BC and assess the utility of these data for ongoing population surveillance.

Methods: Records of viral identifications (1997-2005) were extracted from the Provincial Public Health Microbiology & Reference Laboratory database.

Protective immunity to Chlamydia trachomatis genital infection: evidence from human studies.

Background. Some screening and treatment programs implemented to control Chlamydia trachomatis genital infections and their complications have shown initial reductions in infection prevalence, followed by increases to preprogram levels or higher. One hypothesis is that treatment shortens duration of infection, attenuates development of protective immunity, and thereby, increases risk of reinfection.

A population-based study of infectious syphilis rediagnosis in British Columbia, 1995-2005.

Background: The Canadian province of British Columbia has experienced an ongoing heterosexual infectious syphilis epidemic since July 1997. In this study, we sought to characterize individuals who received a diagnosis of syphilis more than once in a cohort of reported cases from 1995 through 2005 in British Columbia.

Methods: Data for all cases of primary, secondary, and early latent syphilis from 1 January 1995 through 31 December 2005 were extracted from the British Columbia Provincial Sexually Transmitted Disease Surveillance Database.

Considerations on Chlamydia trachomatis disease expression.

Chlamydia disease expression is the result of complex molecular and cellular interactions between the host and a pathogen which appears to have been sculpted by evolutionary forces. Recent genomic, immunologic, and epidemiologic findings are reviewed. A synthesis is offered which suggests that Chlamydia disease expression results from persistent infection and host immune responses.

Seeking sexual partners on the internet: a marker for risky sexual behaviour in men who have sex with men.

Objective: In order to generate a generalizable estimate regarding risk for STI and HIV acquisition in men who have sex with men (MSM) who seek partners on the internet, we examined the sexual practices of MSM who seek partners on the internet compared to MSM who do not, using a community-based sample of MSM from British Columbia.

Methods: 'Sex Now', a questionnaire that was developed to examine trends in sexual behaviour in gay men, was offered to men attending Gay Pride events throughout the province of British Columbia, Canada between May and August 2004. Logistic regression analysis was used to model the association between seeking sexual partners online and other variables of interest, using odds ratio as the measure of association.

A population-based approach to determine the prevalence of transmitted drug-resistant HIV among recent versus established HIV infections: results from the Canadian HIV strain and drug resistance surveillance program.

Objectives: Published results on primary or transmitted HIV drug resistance may be biased because they have been largely derived from specific cohort studies or higher risk individuals who present symptomatically. Here, we present results from a representative population-based study of newly diagnosed cases of HIV in Canada and compare the prevalence of transmitted drug resistance between recent and established infections.

Methods: Available archived sera taken for the purpose of diagnostic HIV testing from all treatment-naive HIV-positive individuals who were newly diagnosed between 2000 and 2001 were tested for recency of infection, HIV-1 subtype, and mutations conferring reduced susceptibility to reverse transcriptase inhibitors and protease inhibitors (PIs).

Sex-work harm reduction.

Sex work is an extremely dangerous profession. The use of harm-reduction principles can help to safeguard sex workers' lives in the same way that drug users have benefited from drug-use harm reduction. Sex workers are exposed to serious harms: drug use, disease, violence, discrimination, debt, criminalisation, and exploitation (child prostitution, trafficking for sex work, and exploitation of migrants).

The unexpected impact of a Chlamydia trachomatis infection control program on susceptibility to reinfection.

Background: After the introduction of a program to control Chlamydia trachomatis infection in British Columbia, Canada, case rates fell from 216 cases/100,000 population in 1991 to 104 cases/100,000 population in 1997. Since 1998, rates have increased, and case counts now exceed those recorded before the intervention.

Methods: We used Cox proportional-hazards survival analysis and developed a compartmental mathematical model to investigate the cause of resurgence in chlamydia cases.

The impact of syphilis mass treatment one year later: self-reported behaviour change among participants.

In 2000, syphilis mass treatment using oral azithromycin was delivered to at-risk British Columbians during a sex trade-related outbreak. The initiative included education, counselling and referral. This cross-sectional, observational study examines knowledge, attitudes and self-reported behaviour after one year among mass treatment participants compared with eligible non-participants.

Prenatal and congenital syphilis in British Columbia.

Objective: To describe the incidence of maternal syphilis and the corresponding rate of infection in exposed neonates in British Columbia before and after a serious outbreak of infectious syphilis in the heterosexual population.

Methods: We conducted a retrospective chart review of pregnant women with positive syphilis serology and reported cases of congenital syphilis in British Columbia from 1994 to 2003. Clinical charts were reviewed for demographic information, staging of maternal syphilis, and stage of pregnancy when treatment was received.

Impact of mass treatment on syphilis transmission: a mathematical modeling approach.

Background: Since 1997 Vancouver (British Columbia, Canada) has experienced an outbreak of heterosexually transmitted infectious syphilis, which prompted a mass treatment campaign in early 2000 in an attempt to control the disease. By 1 year postintervention, syphilis cases had rebounded significantly. We investigate the cause of this postintervention rebound.

Targeted mass treatment for syphilis with oral azithromycin.

From mid 1997 to end of 1999, there was a sexually-transmitted infectious syphilis outbreak mainly in heterosexual people in British Columbia, Canada, that was concentrated in Vancouver. The rate across the province increased from less than 0.5 to 3.