Controlling Tungiasis in an Impoverished Community: An Intervention Study

BackgroundIn Brazil, tungiasis is endemic in some resource-poor communities where various domestic and sylvatic animals act as reservoirs for this zoonosis. To determine the effect of control measures on the prevalence and intensity of infestation of human and animal tungiasis, a repeated cross-sectional survey with intervention was carried out.
Methodology/Principal FindingsIn a traditional fishing community in Northeast Brazil, humans and reservoir animals were treated, and premise-spraying using an insecticide was done, while a second fishing community served as a control. Both communities were followed up 10 times during a 12-month period. At baseline, prevalence of tungiasis was 43% (95% confidence interval [CI]: 35%–51%) and 37% (95% CI: 31%–43%) in control and intervention villages, respectively. During the study, prevalence of tungiasis dropped to 10% (95% CI: 8%–13%; p<0.001) in the intervention village, while the prevalence remained at a high level in the control village. However, after one year, at the end of the study, in both communities the prevalence of the infestation had reached pre-intervention levels. Whereas the intensity of infestation was significantly reduced in the intervention community (p<0.001), and remained low at the end of the study (p<0.001), it did not change in the control village.
Conclusion/SignificanceOur study shows that a reduction of prevalence and intensity of infestation is possible, but in impoverished communities a long-lasting reduction of disease occurrence can only be achieved by the regular treatment of infested humans, the elimination of animal reservoirs, and, likely, through environmental changes.
Trial RegistrationControlled-Trials.com ISRCTN27670575

背景：在巴西，潜蚤病（tungiasis）在部分资源匮乏社区呈地方性流行，各类家养与野生动物均可作为该人畜共患病的储存宿主。为明确防控措施对人与动物潜蚤病感染率及感染强度的影响，本研究开展了一项附带干预措施的重复横断面调查。
方法与主要结果：在巴西东北部的一处传统捕鱼社区，研究人员对人群及储存宿主动物实施了治疗，并使用杀虫剂开展房舍及周边环境喷洒；另一个捕鱼社区作为对照。在12个月的随访周期内，对两个社区共进行了10次追踪调查。基线阶段，对照村与干预村的潜蚤病感染率分别为43%（95%置信区间[CI]：35%–51%）与37%（95% CI：31%–43%）。研究期间，干预村的潜蚤病感染率降至10%（95% CI：8%–13%；p<0.001），而对照村的感染率仍维持在较高水平。然而在1年后研究结束时，两个社区的感染率均回升至干预前水平。干预村的感染强度显著降低（p<0.001），且在研究结束时仍维持较低水平（p<0.001），而对照村的感染强度未发生变化。
结论与意义：本研究表明，降低潜蚤病的感染率与感染强度具备可行性，但在贫困社区，唯有通过对受感染人群的定期治疗、清除动物储存宿主，且可能辅以环境改造，才能实现疾病发生的长效降低。
试验注册：Controlled-Trials.com ISRCTN27670575