最近的证据表明,在一些焦点中,通过伊维菌素的大规模药物管理(MDA),消除非洲的盘尾丝虫病可能是可行的。为了实现大陆消除传播,需要在目前尚不清楚地方性状况的所有实施单位(IU)中进行绘图调查。使用具有优化超参数选择的增强回归树模型,我们估计整个非洲的盘尾丝虫病的环境适用性为5×5公里。为了对包括适合环境的位置的IU进行分类,我们使用受试者工作特征(ROC)分析来确定与先前检测到盘尾丝虫病的位置一致的适合性的最佳阈值.然后使用该阈值基于具有最大平均预测的IU内的位置来对IU(更合适或更不合适)进行分类。对环境适宜性的平均估计表明,西非和中非的大部分地区,以及东非的重点地区,适合盘尾丝虫病传播,与当前控制和消除传播努力的存在相一致。ROC分析确定了0·71的平均环境适用性指数作为阈值,以基于IU内平均预测最大的位置进行分类。在考虑用于测绘调查的IU中,在至少一个5×5公里的位置中,50·2%的适用性超过此阈值。绘制整个非洲大陆盘尾丝虫病流行地图所需的庞大数据收集规模,为使用空间数据确定可能适合盘尾丝虫病传播的区域提供了机会。国家消除盘尾丝虫病计划不妨考虑将这些IU优先用于制图调查,作为人力资源,实验室能力,和计划时间表可能会限制调查的实施,并可能延迟最终合格区域的MDA启动。
Recent evidence suggests that, in some foci, elimination of
onchocerciasis from Africa may be feasible with mass drug administration (MDA) of ivermectin. To achieve continental elimination of transmission, mapping surveys will need to be conducted across all implementation units (IUs) for which endemicity status is currently unknown. Using boosted regression tree models with optimised hyperparameter selection, we estimated environmental suitability for onchocerciasis at the 5 × 5-km resolution across Africa. In order to classify IUs that include locations that are environmentally suitable, we used receiver operating characteristic (ROC) analysis to identify an optimal threshold for suitability concordant with locations where onchocerciasis has been previously detected. This threshold value was then used to classify IUs (more suitable or less suitable) based on the location within the IU with the largest mean prediction. Mean estimates of environmental suitability suggest large areas across West and Central Africa, as well as focal areas of East Africa, are suitable for
onchocerciasis transmission, consistent with the presence of current control and elimination of transmission efforts. The ROC analysis identified a mean environmental suitability index of 0·71 as a threshold to classify based on the location with the largest mean prediction within the IU. Of the IUs considered for mapping surveys, 50·2% exceed this threshold for suitability in at least one 5 × 5-km location. The formidable scale of data collection required to map
onchocerciasis endemicity across the African continent presents an opportunity to use spatial data to identify areas likely to be suitable for
onchocerciasis transmission. National
onchocerciasis elimination programmes may wish to consider prioritising these IUs for mapping surveys as human resources, laboratory capacity, and programmatic schedules may constrain survey implementation, and possibly delaying MDA initiation in areas that would ultimately qualify.