Comparing the Ecological Niches of Chlamydial and Gonococcal Infections in Winnipeg, Canada: 2007-2016.

BACKGROUND: Previous studies have shown substantial differences in geographic clustering of sexually transmitted infections (STI), such as chlamydia (CT) and gonorrhea (NG), conditional on epidemic phase. Chlamydia and NG have recently shown resurgent epidemiology in the northern hemisphere. This study describes the recent epidemiology of CT and NG in Winnipeg, Canada, combining traditional surveillance tools with place-based analyses, and comparing the ecological niches of CT and NG, in the context of their evolving epidemiology. METHODS: Data were collected as part of routine public health surveillance between 2007 and 2016. Secular trends for CT and NG, and CT/NG coinfection were examined. Gini coefficients and population attributable fractions explored the distribution, and concentration of infections over time and space. RESULTS: Rates of CT increased from 394.9/100,000 population to 476.2/100,000 population from 2007 to 2016. Gonorrhea rates increased from 78.0/100,000 population to 143.5/100,000 population during the same period. Each pathogen had its own ecological niche: CT was widespread geographically and socio-demographically, while NG was clustered in Winnipeg's inner-core. CT/NG co-infections had the narrowest space and age distribution. NG was shown to be undergoing a growth phase, with clear signs of geographic dispersion. The expansion of NG resembled the geographic distribution of CT. CONCLUSIONS: We demonstrated that NG was experiencing a growth phase, confirming theoretical predictions of geographic dispersion during a growth phase. During this phase, NG occupied similar geographic spaces as CT. Knowledge of different ecological niches could lead to better targeting of resources for subpopulations vulnerable to STIs.

Observational study of the populations accessing rapid point-of-care HIV testing in Winnipeg, Manitoba, Canada, through a retrospective chart review of site records.

OBJECTIVES: HIV point-of-care testing (POCT) has been available in Manitoba since 2008. This study evaluated the effectiveness of POCT at identifying individuals with previously unknown HIV status, its effects on clinical outcomes and the characteristics of the populations reached. METHODS: A retrospective database review was conducted for individuals who received HIV POCT from 2011 to 2014. Time to linkage to care and viral load suppression were compared between individuals who tested positive for HIV using POCT and controls identified as positive through standard screening. Testing outcomes for labouring women with undocumented HIV status accessing POCT during labour were also assessed. RESULTS: 3204 individuals received POCT (1055 females (32.9%) and 2149 males (67.1%)), being the first recorded HIV test for 2205 (68.8%). Males were more likely to be targeted with POCT as their first recorded HIV test (adjusted OR (AOR) 1.40). Between the two main test sites (Main Street Project (MSP) and Nine Circles Community Health Centre), MSP tested relatively fewer males (AOR 0.79) but a higher proportion of members of all age groups over 30 years old (AOR 1.83, 2.51 and 3.64 for age groups 30-39, 40-49 and >50, respectively). There was no difference in time to linkage to care (p=0.345) or viral load suppression (p=0.405) between the POCT and standard screening cohorts. Of 215 women presenting in labour with unknown HIV status, one was identified as HIV positive. CONCLUSIONS: POCT in Manitoba has been successful at identifying individuals with previously unknown HIV-positive status. Demographic differences between the two main testing sites support that this intervention is reaching unique populations. Given that we observed no significant difference in time to clinical outcomes, it is reasonable to continue using POCT as a targeted intervention. MESH TERMS: HIV infection; rapid HIV testing; vertical infectious disease transmission; community outreach; service delivery; marginalised populations.

Can enhanced screening of men with a history of prior syphilis infection stem the epidemic in men who have sex with men? A mathematical modelling study.

OBJECTIVES: The aim of this study is to determine the transmission impact of using prior syphilis infection to guide a focused syphilis screening intervention among men who have sex with men (MSM). METHODS: We parameterised a deterministic model of syphilis transmission in MSM to reflect the 2011-2015 syphilis outbreak in Winnipeg, Canada. Enhanced screening of 75% of men with prior syphilis every 3 months (A) was compared with distributing equivalent number tests to all MSM (B) or those with the highest partner number (C). We compared early syphilis incidence, diagnoses and prevalence after 10 years, relative to a base case of 30% of MSM screened annually. RESULTS: Strategy A was expected to avert 52% of incident infections, 44% of diagnosed cases and reduce early syphilis prevalence by 89%. Strategy B had the least impact. Strategy C was most effective, averting 59% of incident cases. When screening frequency was semiannual or annual, strategy A was the most effective. CONCLUSIONS: Enhanced screening of MSM with prior syphilis may efficiently reduce transmission, especially when identification of high-risk men via self-reported partner numbers or high-frequency screening is difficult to achieve.

Infectious syphilis in women: what's old is new again?

The aim of this study was to examine trends in infectious syphilis epidemiology among women in Winnipeg, Canada. A descriptive study of syphilis among Winnipeg residents between 2003 and 30 June 2015 was undertaken. Adjusted rate ratios (ARR) and 95% confidence intervals (95%CI) from Poisson regression analyses are reported. Characteristics of men and women were compared using logistic regression, with adjusted odds ratios (AOR) reported. Between 2014 and 2015, the rate of syphilis was 1.7/100,000, representing a five-fold increase since 2006-2013. All cases have been heterosexual, 90% 20-39 years of age, and 59% living in Winnipeg's inner core. Approximately 24% were pregnant at diagnosis; no cases of congenital syphilis have been reported. Compared to men, women were more likely to report alcohol use (AOR: 3.8, 95% CI: 1.2-11.9) and co-infection with chlamydia (AOR: 5.0, 95% CI: 1.1-22.9). In conclusion, the rates of infectious syphilis are increasing among women. Prenatal screening and education for inner-core women and the health care providers serving them should be prioritized.