Ontario researchers call for more STI testing, particularly among gay and bisexual men
30 October 2014 - Common sexually transmitted infections (STIs)-such as herpes, chlamydia, gonorrhea, syphilis, human papilloma virus (HPV)-can cause inflammation and/or sores on, around or
inside the wet delicate tissue lining the anus, mouth/throat, penis and vagina. In some cases, the inflammation and/or sores may be
painless, so affected people may not notice them and so not seek care.
The inflammation caused by STIs may make some people more susceptible to HIV infection.
Among people who already have HIV, STIs can be a problem for at least the following reasons:
- They weaken the immune system and increase the risk of getting other STIs.
- They increase the production of HIV and thereby increase the risk of spreading HIV.
- Germs such as syphilis can quickly spread to vital organs, including the brain.
- There has been an increase in difficult-to-treat strains of gonorrhea and such infections can be extremely unpleasant.
Many common STIs-herpes, chlamydia, gonorrhea, syphilis and HPV-can be spread through condomless oral, vaginal and anal sex.
Thus, regular (and in some cases frequent) medical checkups and screening for STIs are necessary for sexually active adults, particularly
those who have anonymous sex and/or multiple sex partners. Correct and consistent use of condoms is also helpful in providing protection
from many STIs.
For at least the past decade, cases of syphilis and HIV have been rising among gay and bisexual men in Canada and other high-income
countries. Indeed, reports from Canada suggest that cases of syphilis have risen at least 10-fold in that time, particularly among
men who have sex with men (MSM).
Researchers at the Ontario HIV Treatment Network (OHTN) have collaborated with leading HIV clinics in this province to study syphilis
testing. The researchers found that rates of such testing, though increasing, were less than ideal. To remedy this situation, they have
suggestions for both clinics and patients to ensure that more patients are screened and more STIs are detected and treated so that
their spread can decrease.
The Ontario Cohort Study (OCS) collects health-related information from 12 HIV clinics across the province. Participants who volunteered
for the study also completed questionnaires and since 2008 underwent annual interviews. Researchers analysed data from 4,232 participants
collected between the years 2000 and 2009.
The scientists sought and obtained information about syphilis testing by communicating with the Public Health Ontario Laboratories. These
labs provide syphilis testing for the entire province. The sequence of syphilis testing in Ontario is as follows:
- Blood samples are first run through an automated analyser called the Abbott Architect (this checks for antibodies to syphilis).
- If the Architect test result is positive, then confirmatory screening is done with a second test-RPR (rapid plasma reagin),
TPPA ( Treponema pallidum particle agglutination test) or FTA-ABS (fluorescent treponemal antibody absorbed test). These
secondary tests measure antibodies that attack fatty molecules released from cells damaged by the germ ( T. pallidum )
that causes syphilis or, in some cases, from T. pallidum itself.
Researchers at Ontario's public health labs think that this sequence of screening is likely to detect early syphilis cases better than
The basic profile of participants was as follows:
- average age - 45 years
- 86% men, 14% women
- average CD4+ cell count - 455 cells/mm 3
Scientists found that 4,232 participants had 7,313 syphilis tests during the nine-year study period.
Among different populations, the proportion of people who tested for syphilis was as follows:
- MSM - 84%
- women - 78%
- straight men - 75%
Most (86%) syphilis test requests were done by doctors and nurses in HIV clinics. The scientists noted: "Overall, 77% of syphilis tests
were ordered [at the same time as HIV viral load tests]."
Over the course of the study, researchers found that rates of syphilis testing had increased markedly. For instance, in the year 2000
only about 3% of participants had a syphilis test. By the year 2009, about 55% of participants had a syphilis test.
This increase in testing is an improvement over earlier years. However, it is still less than ideal.
Based on the results of testing, the research team estimated that over the lifetime of HIV-positive patients in Ontario "at least one in
five" will have syphilis.
In 2009, the researchers found that at least 4% of MSM in their study had a new case of syphilis.
Other studies in Western Europe and Australia have found broadly similar rates of syphilis in MSM, particularly HIV-positive MSM, as in the Ontario study.
Bear in mind that due to issues related to the design of the study, it is extremely likely that the research team underestimated the cases of syphilis in HIV-positive MSM in Ontario.
- Cases of syphilis have increased in many regions since the year 2000, in some cases by at least tenfold.
- According to Ontario researchers, "the vast majority of [syphilis cases are] among MSM, many of whom are co-infected with HIV."
- Although rates of syphilis testing have increased over time, they are still less than ideal.
- The researchers stated that they ".recommend that future efforts to improve timely detection and treatment of syphilis in [HIV-positive
MSM] include systematic and operational changes to health care practice, such as clinic-based interventions."
- The study's findings underscore the need for sexually active adults, particularly gay and bisexual men, to have regular, and in some
cases frequent, medical checkups and screening for STIs and prompt treatment when such STIs are diagnosed. Sexually active adults can
reduce their risk for STIs by consistent and correct use of condoms.
Syphilis - CATIE fact sheet
What the syph is
going on? Responding to syphilis outbreaks in Canada - Prevention in Focus
Management and Treatment of Specific
Infections: Syphilis - Canadian Guidelines on Sexually Transmitted Infections
treatment STBBI: Syphilis - L'Institut national d'excellence en santé et en services sociaux (INESSS)
New information for gay men living-with HIV: STI testing is good for your health - Ontario HIV Treatment Network
-Sean R. Hosein
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From Canadian AIDS Treatment Information Exchange (CATIE). For more information visit CATIE's Information Network at http://www.catie.ca
Source: CATIE: CANADIAN AIDS TREATMENT INFORMATION EXCHANGE