Syphilis in New South Wales. (Australia) prisons. Tony Butler1, Peter Robertson2, John Kaldor3 and Basil Donovan4,5. 1New South Wales Corrections Health ...
International Journal of STD & AIDS 2001; 12: 376± 379
ORIGINAL ARTICLE
Syphilis in New South Wales (Australia) prisons Tony Butler1, Peter Robertson2, John Kaldor3 and Basil Donovan4,5 1New
South Wales Corrections Health Service, Long Bay Correctional Centre, Malabar, Sydney, 2South Eastern Area Laboratory Service, Prince of Wales Hospital, Randwick, 3National Centre in HIV Epidemiology and Clinical Research, University of New South Wales, Sydney, 4Sydney Sexual Health Centre, Sydney Hospital, Sydney and 5Department of Public Health and Community Medicine, University of Sydney, Australia Summary: This paper describes the prevalence of, and risk factors for, exposure to syphilis in a random sample of male and female prisoners. We found that only 2% of male and 1% of female prison inmates in New South Wales (NSW) had con® rmed evidence of untreated syphilis, and none appeared to be in an infectious phase. In the multivariate analysis, indigenous ethnicity remained the most potent predictor for con® rmed syphilis (either past or present). There was some evidence to suggest that syphilis among indigenous prisoners may be associated with limited access to health services outside prison. The epidemiology of syphilis re¯ ects that of the general community suggesting that prisons could be used as sentinel sites to help evaluate the effectiveness of STD prevention and control strategies. Keywords: Prisoners, sexually transmitted diseases, indigenous, syphilis
INTRODUCTION Sexually transmissible diseases (STDs) tend to cluster in socially excluded populations and Ð virtually by de® nition Ð such populations are over-represented in prisons. Consequently, numerous studies have found high rates of STDs in prison populations, including syphilis1± 8. The fourth Australian National HIV/AIDS Strategy has therefore given priority to prisons as potential `transitional’ environments for the spread of blood-borne and sexually transmissible infections 9. Within Australia it has been estimated that over 90% of incident syphilis infections occur among indigenous people10, particularly those living in rural and remote areas where health services may be scant11. In those same areas, diversionary options are also limited so young indigenous people have a high likelihood of going to prison. Though indigenous people comprised only 1% of the total population of NSW in 1996, they accounted for 14% of the NSW prisoner population. NSW is home to about one-quarter of the indigenous population of Australia. As part of a more general survey of the health and welfare of NSW prisoners we sought to determine the prevalence and risk factors for syphilis in a representative sample of NSW prisoners. Other Correspondence to: Tony Butler, NSW Corrections Health Service, PO Box 150, Matraville, NSW 2036, Australia E-mail: butlert@chs.health.nsw.gov.au
results of the same study Ð including histories of childhood sexual assault; sexual behaviour while in prison; herpes simplex virus type 2, HIV, hepatitis C and hepatitis B virus infections Ð have been reported elsewhere7,8,12,13. METHODS A representative sample of 657 male and 132 female prisoners from 27 correctional facilities was selected as previously described 7,12,13. The sample comprised approximately 11% of full-time males and 40% of full-time female prisoners in NSW in 1996, and included 235 indigenous prisoners. Histories of syphilis and demographic and behavioural risk factors were derived from nurseadministered questionnaires. Serum from each prisoner was screened by both a rapid plasma reagin (RPR) test and a Treponema pallidum particle agglutination (TPPA) test. A reactive or weakly reactive result to either test led to a ¯ uorescent treponemal antibody (absorption)(FTA-Abs) con® rmatory test. A repeatedly uncon® rmed positive RPR or TPPA test was deemed to be a false positive result (Table 1). Testing for herpes simplex virus type 2, hepatitis B virus, and hepatitis C virus antibodies was by enzyme immunoassay as previously described 8,12. For indigenous prisoners, the last address used before entering prison was used as a surrogate measure of access to health services before entering prison. They were dichotomosed into living in a
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Butler et al. Syphilis in New South Wales (Australia) prisons
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Table 1. Syphilis status of NSW prisoners
History/Test result No history of syphilis/non-reactive RPR and TPPA No history of syphilis/non-reactive or weakly reactive RPR, reactive TPPA and FTA(Abs) Past history of syphilis treatment/nonreactive or weakly reactive RPR, reactive TPPA and FTA(Abs) tests No history of syphilis/reactive RPR,* nonreactive TPPA and FTA(Abs) No history of syphilis/non-reactive RPR, reactive TPPA non-reactive FTA(Abs) Past history of syphilis/non-reactive RPR, TPPA and FTA(Abs)
No. of females n= 119 (%)
No. of males n= 629 (%)
Interpretation
111 (93)
585 (93)
No syphilis
1 (1)
12 (2 )
1 (1)
4 (1)
Adequately treated syphilis
2 (2)
6 (1)
False positive RPR test
0 (0)
1 (0.2)
False positive TPPA test
3 (3)
17 (3)
Untreated latent syphilis
Previous syphilis diagnosis doubtful
*All except one were weakly reactive. RPR= rapid plasma reagin test, TPPA= Treponema pallidum particle agglutination test, FTA(Abs)= ¯ uorescent treponemal antibody (absorption) test
`highly accessible’ area or in any of the other 4 categories Ð `accessible’ through `very remote’ Ð according to the accessibility/remoteness index of Australia (ARIA) score14. All prisoners with previously undiagnosed syphilis were treated according to current guidelines 15. Ethics approval for the study was independently granted by the NSW Department of Corrective Services and the NSW Corrections Health Service. Odds ratios and Chi-square values for associations with con® rmed syphilis (2 positive treponemal tests) were analysed using SAS 8.0116. Variables that approached signi® cance (PMedian age 20 Born outside Australia No Yes History of STDs No Yes HSV-2 antibody No Yes HBV antibody No Yes HCV antibody No Yes Injecting drug use No Yes History of same sex partners Heterosexual Homosexual/bisexual Self-reported health status Poor/fair Good/excellent
N
Syphilis (%)
629 119
Univariate
Multivariate
OR
P value
95% CI
OR
P value
95% CI
3.2 2.5
1.0 0.8
0.7
0.2± 2.7
518 230
0.2 9.6
1.0 54.7
0.0001
7.3± 408.3
1.0 30.5
0.001
3.8± 243.7
395 353
3.8 2.3
1.0 0.6
0.2
0.2± 1.4
1.0 0.6
0.4
0.2± 1.9
419 273
2.9 2.9
1.0 1.0
0.9
0.4± 2.5
434 240
2.1 4.6
1.0 2.3
0.07
0.9± 5.6
1.0 3.5
0.02
1.2± 10.3
602 93
3.2 1.1
1.0 0.3
0.3
0.04± 2.5
530 218
2.1 5.5
1.0 2.7
0.01
1.2± 6.3
1.0 2.2
0.14
0.8± 6.2
546 201
2.0 6.0
1.0 3.1
0.006
1.3± 7.1
1.0 2.2
0.13
0.8± 6.2
480 263
1.3 6.5
1.0 5.5
0.0001
2.1± 14.0
1.0 3.9
0.02
1.3± 11.7
450 288
4.4 1.0
1.0 0.2
0.009
0.1± 0.8
1.0 0.2
0.007
0.04± 0.6
332 106
1.8 0.9
1.0 0.5
0.5
0.1± 4.3
611 70
3.0 2.9
1.0 0.9
0.9
0.2± 4.2
492 206
3.7 1.0
1.0 0.3
0.05
0.1± 1.1
1.0 0.3
0.09
0.05± 1.2
*Previous or current (n= 23). HSV-2= herpes simplex virus type 2, HBV= hepatitis B virus, HCV= hepatitis C virus
screening Ð as has been the practice in prison surveys elsewhere1± 6 Ð only 8 (1.3%) of the males and none of the females would have been diagnosed with untreated syphilis. Broadly, these ® ndings were consistent with our understanding of the current epidemiology of syphilis in Australia10,11. Indigenous ethnicity was the strongest predictor of previous or current syphilis. In NSW the highest syphilis noti® cation rates come from rural and remote areas with the highest concentrations of indigenous people17. The roughly equal prevalence of syphilis markers among indigenous men and women implied predominantly heterosexual transmission. While there was a suggestion that limited access to health services outside prison was associated with
syphilis among indigenous prisoners, we used a relatively crude surrogate measure. Future studies should employ a more reliable measure of this potentially important structural risk factor. Predictably, syphilis was also independently associated with hepatitis B antibodies and with greater reported numbers of sexual partners. However we are unsure why hepatitis C antibodies were so `protective’ for syphilis. One consideration is that injecting drugs was a relatively recent phenomenon among indigenous populations at the time of the survey so that the hepatitis C virus may not have had suf® cient time to widely disseminate. We previously found that indigenous ethnicity was associated with a decreased risk of hepatitis C12.
Butler et al. Syphilis in New South Wales (Australia) prisons
In this population we found that a self-reported history of syphilis was very unreliable. It is possible that some may have been misdiagnosed with other ulcerative disease: most prisoners with dubious prior syphilis had serological evidence of genital herpes. As we previously reported, less than 1% of the sample with antibodies to herpes simplex virus type 2 reported a prior diagnosis of genital herpes 8. Equally, some of the prisoners may not have understood the question or not have known what syphilis is. Self-reports of STDs in poorly served populations can be misleading18. Wherever possible biological data should be collected to assess these reports. In conclusion, we found only a limited pool of undiagnosed latent syphilis in this otherwise highrisk population. Nevertheless, as they re¯ ect the epidemiology of syphilis in the general community, prisons could be used as sentinel sites to help evaluate the effectiveness of STD prevention and control strategies. Acknowledgements: We wish to thank the NSW Corrections Health Service and the NSW Health Department for providing ® nancial support for the project and the Department of Corrective Services for granting permission to conduct the survey. We would also like to thank all of the interviewers who collected the blood specimens and administered the questionnaires. References 1
2
3 4
Alexander-Rodriguez T, Vermund S. Gonorrhoea and syphilis in incarcerated urban adolescents: prevalence and physical signs. Pediatrics 1987;80:561± 4 Beidinger H, Jenks J, Broussard D. Syphilis screening among women arrestees at the Cook County Jail Ð Chicago, 1996. MMWR 1999;47:432± 3 Martin J, Much D. Sexually transmitted diseases in prison women. Penn Med 1998;April:40± 2 Miranda AE, Vargas PM, St Louis ME, Viana MC. Sexually transmitted disease among female prisoners in Brazil: prevalence and risk factors. Sex Transm Dis 2000;27: 491± 5
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(Accepted 10 January 2001)
