Trends of syphilis in Brazil: a growth portrait of the treponemic epidemic

Syphilis is a chronic infectious disease with its prevalence being described since the 15^th century. Although its etiological agent and also the treatment measures are widely known, syphilis is still a great public health problem worldwide, mainly in countries with limited resources associated to low investments in health primary care. The aim of the present study was to analyze the trend and regional distribution of syphilis in Brazil between 2007 and 2017. This is an ecological study using secondary data from the Brazilian notification system. The Ministry of Health selected 100 municipalities which presented the worse outcomes related to syphilis from the 5,570 Brazilian municipalities as a target for a comprehensive project in order to tackle the prevalence of syphilis, called the “No Syphilis Project”. These priority municipalities represent 57.7% of syphilis cases and about one third of the Brazilian population. They were compared with other 189 non-priority municipalities with more than 100 thousand inhabitants among the Brazilian regions (North, Northeast, Southeast, South and Center-West). Polynomial regression methods and Joinpoint analyses were used to analyze the trend, from which the Annual Average Percent Change (AACP) for each time period was calculated. There was a significant growth trend in all regions for the main three forms of syphilis (in pregnancy, congenital and acquired), especially in the South. The ratio between syphilis in pregnancy and congenital syphilis increased in both priority (AAPC: 8.54%; <i>p</i>&lt;0.001) and non-priority municipalities (AAPC: 2.61%; <i>p</i>=0.005), as well as in the regions, except the Center-West. High growth trends in syphilis prevalence were found in all municipalities, as well as all five regions between 2007 and 2017, showing that the challenge to reduce or even eliminate syphilis in Brazil is still difficult.

梅毒是一种慢性传染性疾病，其流行情况自15世纪起便有史料记载。尽管其病原体与治疗方案已广为人知，但梅毒仍是全球范围内的重大公共卫生难题，在初级卫生保健投入不足的资源匮乏国家尤为凸显。本研究旨在分析2007至2017年间巴西梅毒的流行趋势与区域分布特征。本研究为生态学研究，数据来源于巴西传染病报告系统的二手数据。巴西卫生部从全国5570个市镇中遴选出100个梅毒防控成效最差的市镇，作为"无梅毒项目（No Syphilis Project）"的综合防控试点对象，以应对梅毒流行问题。上述重点防控市镇的梅毒病例数占全国总病例数的57.7%，覆盖巴西约三分之一的人口。研究将其与巴西五大区域（北部、东北部、东南部、南部及中西部）内其余189个人口超10万的非重点市镇进行对比。本研究采用多项式回归法与连接点（Joinpoint）分析法分析流行趋势，并计算各时间段的年度平均百分比变化（Annual Average Percent Change, AACP）。巴西所有区域的三大主要梅毒类型（妊娠梅毒、先天性梅毒与获得性梅毒）均呈现显著增长趋势，南部区域尤为突出。妊娠梅毒与先天性梅毒的病例比值在重点市镇（AAPC：8.54%；p<0.001）与非重点市镇（AAPC：2.61%；p=0.005）均有所上升，除中西部区域外的所有巴西区域也呈现相同趋势。2007至2017年间，巴西所有市镇及五大区域的梅毒流行率均呈现高速增长态势，这表明在巴西降低乃至消除梅毒仍是一项极具挑战性的任务。