Improving the efficiency of reactive case detection for malaria elimination in southern Zambia: a cross-sectional study
Improving the efficiency of reactive case detection for malaria elimination in southern Zambia: a cross-sectional study
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DOI：
10.1186/s12936-020-03245-1
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发表时间：
2020-05-07
期刊：
影响因子：
3
通讯作者：
Moss, William J.
中科院分区：
文献类型：
--
作者：
Bhondoekhan, Fiona R. P.;Searle, Kelly M.;Moss, William J.
反应性病例检测（RCD）旨在通过识别和治疗居住在指示病例附近的寄生虫个体来加强疟疾监测和控制。在赞比亚，这一战略首先是在当地卫生机构或由社区卫生工作者被动发现有症状的疟疾病例，随后使用快速诊断测试（RDTs）对指示病例的筛查和治疗居民以及140米半径范围内的邻近（二级）家庭进行家访。然而，小的圆形半径可能不是在疟疾传播热点低流行地区识别寄生虫个体的最有效策略。为了评估是否可以通过增加识别寄生虫居民的概率来提高RCD效率，在疟疾低流行地区评估了环境风险因素和更大的筛查半径（250 m）。方法2015年1月12日至2017年7月26日，在赞比亚南部省乔马区马查医院集水区对居住在158个指标家庭和531个二级家庭的4170人进行调查，并填写基线问卷。采用PfHRP2 rdt和定量PCR （qPCR）检测恶性疟原虫的流行情况。利用Quickbird （TM）高分辨率卫星图像在ArcGIS中创建环境风险因素，并利用广义估计方程评估风险因素与有寄生虫个体的第二家庭之间的关系。结果继发病例（非指数病例）家庭寄生虫流行率RDT为0.7%，qPCR为1.8%。总体而言，通过qPCR或RDT， 8.5% （n = 45）的第二家庭至少有一名居民患有寄生虫病。第二家庭中有寄生居民的风险在靠近较高顺序流的地方显著增加，与指数家庭的距离增加则略有增加。靠近三级和五级河流的调整OR分别为2.97 （95% CI 1.04-8.42）和2.30 (95% CI 1.04-5.09)，每50米距离指数家庭的调整OR为1.24 （95% CI 0.98-1.58）。结论将靠近溪流作为筛查工具，与使用140 m圆形筛查半径相比，鉴定出的疟疾阳性第二家庭多16% （n = 3）。该分析强调了环境风险因素作为一种提高RCD效率的筛选策略的潜在用途。
Background Reactive case detection (RCD) seeks to enhance malaria surveillance and control by identifying and treating parasitaemic individuals residing near index cases. In Zambia, this strategy starts with passive detection of symptomatic incident malaria cases at local health facilities or by community health workers, with subsequent home visits to screen-and-treat residents in the index case and neighbouring (secondary) households within a 140-m radius using rapid diagnostic tests (RDTs). However, a small circular radius may not be the most efficient strategy to identify parasitaemic individuals in low-endemic areas with hotspots of malaria transmission. To evaluate if RCD efficiency could be improved by increasing the probability of identifying parasitaemic residents, environmental risk factors and a larger screening radius (250 m) were assessed in a region of low malaria endemicity. Methods Between January 12, 2015 and July 26, 2017, 4170 individuals residing in 158 index and 531 secondary households were enrolled and completed a baseline questionnaire in the catchment area of Macha Hospital in Choma District, Southern Province, Zambia. Plasmodium falciparum prevalence was measured using PfHRP2 RDTs and quantitative PCR (qPCR). A Quickbird (TM) high-resolution satellite image of the catchment area was used to create environmental risk factors in ArcGIS, and generalized estimating equations were used to evaluate associations between risk factors and secondary households with parasitaemic individuals. Results The parasite prevalence in secondary (non-index case) households was 0.7% by RDT and 1.8% by qPCR. Overall, 8.5% (n = 45) of secondary households had at least one resident with parasitaemia by qPCR or RDT. The risk of a secondary household having a parasitaemic resident was significantly increased in proximity to higher order streams and marginally with increasing distance from index households. The adjusted OR for proximity to third- and fifth-order streams were 2.97 (95% CI 1.04-8.42) and 2.30 (95% CI 1.04-5.09), respectively, and that for distance to index households for each 50 m was 1.24 (95% CI 0.98-1.58). Conclusion Applying proximity to streams as a screening tool, 16% (n = 3) more malaria-positive secondary households were identified compared to using a 140-m circular screening radius. This analysis highlights the potential use of environmental risk factors as a screening strategy to increase RCD efficiency.