Primary syphilis cases in Guangdong Province 1995-2008: opportunities for linking syphilis control and regional development.

Li-Gang Yang,Xi-Feng Sun,Bin Yang,Joseph D Tucker,Xiang-Sheng Chen,Yong-Feng Chen,Song-Ying Shen

doi:10.1186/1471-2458-10-793

Abstract

BackgroundSyphilis cases have risen in many parts of China, with developed regions reporting the greatest share of cases. Since syphilis increases in these areas are likely driven by both increased screening and changes in sexual behaviours, distinguishing between these two factors is important. Examining municipal-level primary syphilis cases with spatial analysis allows a more direct understanding of changing sexual behaviours at a more policy-relevant level.MethodsIn this study we examined all reported primary syphilis cases from Guangdong Province, a southern province in China, since the disease was first incorporated into the mandatory reporting system in 1995. Spatial autocorrelation statistics were used to correlate municipal-level clustering of reported primary syphilis cases and gross domestic product (GDP).ResultsA total of 52,036 primary syphilis cases were reported over the period 1995-2008, and the primary syphilis cases increased from 0.88 per 100,000 population in 1995 to 7.61 per 100,000 in 2008. The Pearl River Delta region has a disproportionate share (44.7%) of syphilis cases compared to other regions. Syphilis cases were spatially clustered (p = 0.01) and Moran's I analysis found that syphilis cases were clustered in municipalities with higher GDP (p = 0.004).ConclusionsPrimary syphilis cases continue to increase in Guangdong Province, especially in the Pearl River Delta region. Considering the economic impact of syphilis and its tendency to spatially cluster, expanded syphilis testing in specific municipalities and further investigating the costs and benefits of syphilis screening are critical next steps.

Highlights

Syphilis cases have risen in many parts of China, with developed regions reporting the greatest share of cases
Cross-sectional epidemiology studies among MSM in Guangdong Province have found a high prevalence of both syphilis [5,6] and HIV infection [5,7]
The diversity of secondary syphilis clinical manifestations makes this a less sensitive indicator of temporal changes in high risk sexual behaviours, so this study focused on changes in primary syphilis cases

Summary

Introduction

Syphilis cases have risen in many parts of China, with developed regions reporting the greatest share of cases. Since syphilis increases in these areas are likely driven by both increased screening and changes in sexual behaviours, distinguishing between these two factors is important. A commonly used term for syphilis infection in Southern China is “Guangdong boils”, thought to be related to the historical position of Guangdong as an important economic and trade hub that has concomitantly suffered from substantial syphilis epidemics in the past. Syphilis is the second most commonly reported communicable disease in Guangdong Province. A study in southern Guangdong Province among 477,656 pregnant women screened for syphilis found 0.5% had a positive treponemal test [4]. Cross-sectional epidemiology studies among MSM in Guangdong Province have found a high prevalence of both syphilis [5,6] and HIV infection [5,7].

Objectives

Methods

Results

Discussion

Conclusion