Risk factors associated to the carriage of HD.

Epidemics of yaws-like cutaneous ulcers are regularly documented in children in the tropics. They occur mainly in poor and remote communities without access to health facilities. The integration of molecular tools into yaws control efforts has made it possible to describe Haemophilus ducreyi (HD) as a major cause of cutaneous ulcers. The objective of this study was to determine the prevalence of HD as cause of cutaneous ulcers, investigate its presence in asymptomatic individuals and identify associated risk factors. A cross-sectional study was conducted in yaws endemic districts of Cameroon. Participants included people presenting yaws-like ulcers and asymptomatic individuals. Swab samples were collected from each participant and tested for HD and Treponema pallidum (TP) using an established qPCR method. Additionally, demographic, habitat, proximity, and hygiene characteristics were collected using a structured questionnaire. A total of 443 individuals participated in the study, including 271 ulcer cases and 172 asymptomatic contacts. The prevalence of HD in ulcers was 30.3% (Confidence Interval (CI) 95% [24.8–35.7]) and the prevalence of asymptomatic HD carriage was 8.6% (CI95% [4.5–12.9]). TP was also detected in our sample among ulcer cases but in lower proportion (5.2% CI95% [2.5–7.8]) compared to HD. The adjusted logistic regression model showed that women were as much at risk of having HD cutaneous ulcer as men regardless of age. Physical proximity to a confirmed ulcer case was the major factor identified favouring HD transmission. HD ulcers were more likely to be present on Bantu individuals compared to Baka as well as HD colonization. These findings highlight HD as the most common cause of cutaneous ulcers in yaws-endemic communities in Cameroon. The exact implications of detecting HD on intact skin are not yet clear. Further studies are needed to understand the significance of this carriage in the spread dynamics of the disease.热带地区儿童的雅司样皮肤溃疡（yaws-like cutaneous ulcers）疫情常被文献报道。此类溃疡主要发生在缺乏医疗资源的贫困偏远社区。将分子检测技术整合至雅司病（yaws）防控工作中，使得杜克雷嗜血杆菌（Haemophilus ducreyi, HD）被明确为皮肤溃疡的主要致病原成为可能。本研究旨在明确HD作为皮肤溃疡致病原的流行率，调查其在无症状个体中的携带情况，并识别相关危险因素。研究在喀麦隆雅司病（yaws）流行地区开展了一项横断面研究（cross-sectional study）。研究对象包括出现雅司样溃疡的患者与无症状接触者。研究人员从每名参与者身上采集拭子样本，采用已建立的qPCR（quantitative real-time PCR）方法检测HD与梅毒螺旋体（Treponema pallidum, TP）。此外，通过结构化问卷收集了人口学特征、居住环境、接触史与卫生习惯相关信息。本研究共纳入443名参与者，其中271名溃疡患者与172名无症状接触者。溃疡样本中HD的检出率为30.3%（95%置信区间（Confidence Interval, CI）[24.8–35.7]），无症状HD携带率为8.6%（95%CI [4.5–12.9]）。研究样本中也在溃疡患者中检出了TP，但其占比（5.2%，95%CI [2.5–7.8]）低于HD。校正后的逻辑回归模型（logistic regression model）显示，无论年龄如何，女性与男性罹患HD相关性皮肤溃疡的风险相当。与确诊溃疡病例的近距离接触是证实的促进HD传播的主要危险因素。相较于巴卡人（Baka），班图人（Bantu）出现HD相关性溃疡以及HD定植的概率更高。本研究结果表明，HD是喀麦隆雅司病流行社区中皮肤溃疡最常见的致病原。在完整皮肤上检出HD的确切意义尚不明确，仍需开展进一步研究以阐明该携带现象在疾病传播动态中的作用。