The impact of a single round of community mass treatment with azithromycin on disease severity and ocular Chlamydia trachomatis load in treatment-naive trachoma-endemic island communities in West Africa
The impact of a single round of community mass treatment with azithromycin on disease severity and ocular Chlamydia trachomatis load in treatment-naive trachoma-endemic island communities in West Africa
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DOI：
10.1186/s13071-017-2566-x
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发表时间：
2017-12-28
影响因子：
3.2
通讯作者：
Bailey, Robin L.
中科院分区：
文献类型：
--
作者：
Last, Anna R.;Burr, Sarah E.;Bailey, Robin L.
背景：沙眼是一种被忽视的热带病，由眼部感染沙眼衣原体引起。世界卫生组织（世卫组织）建议，如果1-9岁儿童滤泡性沙眼（TF1-9）的患病率在地区一级超过10%，每年进行三轮社区大规模阿奇霉素（MDA）药物治疗，以实现之后将地区一级TF1-9的消除目标降至5%以下。为了在几内亚比绍的沙眼流行岛屿社区评估这一策略，我们在四个岛屿进行了一项以人口为基础的横断面沙眼调查。对每位参与者的上睑结膜进行沙眼临床评估，并获得结膜拭子（n = 1507）。我们使用微滴数字PCR检测Ct感染并估计细菌负荷。我们在第二次横断面调查中访问了相同的家庭，并在MDA后一年对这些家庭进行了眼科检查并获得结膜拭子（n = 1029）。结果：mda前TF1-9为22.0%（136/618）。总体Ct感染率（CtI）为18.6%（1-9岁为25.4%）。mda（估计覆盖率70%）后，1-9岁儿童TF1-9和CtI分别显著降低(7.4% （29/394,P < 0.001）和3.3% (34/1029,P < 0.001) （6.6%, P < 0.001）。中位眼Ct负荷从2038份/拭子降至384份/拭子（P < 0.001）。MDA后Ct感染呈高度聚集性（Moran’s I = 0.27, P < 0.05）。总体而言，Ct感染聚集性较少，高负荷感染病例聚集性较少，疾病严重程度较低。结论：尽管Ct感染聚集性病例的数量、平均Ct载量、疾病严重程度和高负荷Ct感染聚集性病例的存在显著减少，表明孤岛社区沙眼控制开始，但在一轮MDA之后，我们证明传播仍在继续。这些详细的数据有助于了解MDA背景下眼部Ct感染的流行病学，所采用的工具可能在类似环境下确定沙眼消除和监测活动方面具有实用价值。
Background: Trachoma, a neglected tropical disease, is caused by ocular infection with Chlamydia trachomatis (Ct). The World Health Organization (WHO) recommends three annual rounds of community mass drug treatment with azithromycin (MDA) if the prevalence of follicular trachoma in 1-9 year olds (TF1-9) exceeds 10% at district level to achieve an elimination target of district-level TF1-9 below 5% after. To evaluate this strategy in treatment-naive trachomaendemic island communities in Guinea Bissau, we conducted a cross-sectional population-based trachoma survey on four islands. The upper tarsal conjunctivae of each participant were clinically assessed for trachoma and conjunctival swabs were obtained (n = 1507). We used a droplet digital PCR assay to detect Ct infection and estimate bacterial load. We visited the same households during a second cross-sectional survey and repeated the ocular examination and obtained conjunctival swabs from these households one year after MDA (n = 1029).Results: Pre-MDA TF1-9 was 22.0% (136/618). Overall Ct infection prevalence (CtI) was 18.6% (25.4% in 1-9 year olds). Post-MDA (estimated coverage 70%), TF1-9 and CtI were significantly reduced (7.4% (29/394, P < 0.001) and 3.3% (34/1029, P < 0.001) (6.6% in 1-9 year olds, P < 0.001), respectively. Median ocular Ct load was reduced from 2038 to 384 copies/swab (P < 0.001). Following MDA cases of Ct infection were highly clustered (Moran's I 0.27, P < 0. 001), with fewer clusters of Ct infection overall, fewer clusters of cases with high load infections and less severe disease.Conclusions: Despite a significant reduction in the number of clusters of Ct infection, mean Ct load, disease severity and presence of clusters of cases of high load Ct infection suggesting the beginning of trachoma control in isolated island communities, following a single round of MDA we demonstrate that transmission is still ongoing. These detailed data are useful in understanding the epidemiology of ocular Ct infection in the context of MDA and the tools employed may have utility in determining trachoma elimination and surveillance activities in similar settings.