Declining trend of serological syphilis among genitourinary medicine patients in the Gambia, West Africa.
BACKGROUND
Syphilis is a common disease in Africa and may be an important contributor to the HIV epidemic. Trends in syphilis prevalence are important in their own right and because syphilis is a cofactor for HIV infection. In this study we analyzed trends in serological syphilis prevalence at a sexually transmitted infections (STI) clinic in The Gambia.


METHODS
At the Genitourinary Medicine clinic of the Medical Research Council in The Gambia patients were routinely screened for syphilis using a 2-test algorithm, measuring rapid plasma reagin followed by the Treponema pallidum haemagglutination assay. Serological syphilis was defined as both tests being positive. We determined year to year trends in serological syphilis. Logistic regression was used to identify risk factors.


RESULTS
Over the period 1994-2007, 23,674 people were tested for syphilis. The prevalence of serological syphilis dropped from 11.2% in 1994 to 1.5% in 2007 (P <0.0001; chi test for trend). Significant risk factors for serological syphilis in women were found to be ethnicity, commercial sex work, and HIV infection. No associations between serological syphilis and possible risk factors in men were found.


CONCLUSIONS
This study identified a strong and significant downward trend in the prevalence of serological syphilis among patients attending the Genitourinary Medicine clinic in The Gambia in the period 1994-2007. These results suggest that syphilis prevalence may be declining in the general population, in the absence of a targeted control program. Research is needed to identify the reasons for this decline.
Hontelez
Jan A C
JA
Medical Research Council Laboratories, Fajara, The Gambia.
van der Loeff
Maarten F Schim
MF
Peterson
Ingrid
I
Peterson
Kevin
K
Ahadzie
Bankhole
B
Cotten
Matthew
M
Sarge-Njie
Ramu
R
Whittle
Hilton
H
D000293:Adolescent; D000328:Adult; D000554:Ambulatory Care Facilities / Q000706:statistics & numerical data*; D005260:Female; D005714:Gambia / Q000453:epidemiology; D015658:HIV Infections / Q000150:complications / Q000453:epidemiology / Q000821:virology; D015497:HIV-1; D015498:HIV-2; D006801:Humans; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D015995:Prevalence; D012307:Risk Factors; D011477:Sex Work; D012749:Sexually Transmitted Diseases / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D013587:Syphilis / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D013588:Syphilis Serodiagnosis; D014210:Treponema pallidum; D055815:Young Adult