Lovato Raquel, Guevara Angel, Guderian Ronald, Proaño Roberto, Unnasch Thomas, Criollo Hipatia, Hassan Hassan K, Mackenzie Charles D
Ecuadorian Onchocerciasis Program, Ministerio de Salud Pública, Quito, Ecuador.
Centro de Biomedicina, Laboratorio de Parasitología Molecular, Escuela de Medicina, Universidad Central del Ecuador, Quito, Ecuador.
PLoS Negl Trop Dis. 2014 May 22;8(5):e2821. doi: 10.1371/journal.pntd.0002821. eCollection 2014 May.
A clinically significant endemic focus of onchocerciasis existing in Esmeraldas Province, coastal Ecuador has been under an ivermectin mass drug administration program since 1991. The main transmitting vector in this area is the voracious blackfly, Simulium exiguum. This paper describes the assessments made that support the decision to cease mass treatment.
Thirty-five rounds of ivermectin treatment occurred between 1991-2009 with 29 of these carrying >85% coverage. Following the guidelines set by WHO for ceasing ivermectin distribution the impact on parasite transmission was measured in the two vector species by an O-150 PCR technique standard for assessing for the presence of Onchocerca volvulus. Up to seven collection sites in three major river systems were tested on four occasions between 1995 and 2008. The infectivity rates of 65.0 (CI 39-101) and 72.7 (CI 42-116) in 1995 dropped to zero at all seven collection sites by 2008. Assessment for the presence of antibodies against O. volvulus was made in 2001, 2006, 2007 and 2008 using standard ELISA assays for detecting anti-Ov16 antibodies. None of total of 1810 children aged 1-15 years (between 82 and 98% of children present in the surveyed villages) tested in the above years were found to be carrying antibodies to this antigen. These findings were the basis for the cessation of mass drug treatment with ivermectin in 2009.
This fulfillment of the criteria for cessation of mass distribution of ivermectin in the only known endemic zone of onchocerciasis in Ecuador moves the country into the surveillance phase of official verification for national elimination of transmission of infection. These findings indicate that ivermectin given twice a year with greater than 85% of the community can move a program to the final stages of verification of transmission interruption.
自1991年以来，厄瓜多尔沿海的埃斯梅拉达斯省存在一个盘尾丝虫病的临床显著流行区，一直在实施伊维菌素群体服药计划。该地区主要的传播媒介是贪婪的蚋，微小蚋。本文描述了所做的评估，这些评估支持了停止群体治疗的决定。
1991年至2009年期间进行了35轮伊维菌素治疗，其中29轮覆盖率超过85%。按照世界卫生组织制定的停止伊维菌素分发的指导方针，通过用于评估盘尾丝虫存在情况的O-150 PCR技术，对两种媒介物种中寄生虫传播的影响进行了测量。1995年至2008年期间，在三个主要河流系统的多达七个采集点进行了四次检测。1995年的感染率分别为65.0（置信区间39 - 101）和72.7（置信区间42 - 116），到2008年，所有七个采集点的感染率均降至零。2001年、2006年、2007年和2008年，使用检测抗Ov16抗体的标准ELISA检测方法，对盘尾丝虫抗体的存在情况进行了评估。在上述年份检测的1810名1至15岁儿童（占被调查村庄儿童的82%至98%）中，没有发现携带针对该抗原的抗体。这些发现是2009年停止伊维菌素群体药物治疗的依据。
在厄瓜多尔唯一已知的盘尾丝虫病流行区满足停止伊维菌素群体分发的标准，使该国进入官方核实全国消除感染传播的监测阶段。这些发现表明，每年两次给予社区超过85%的伊维菌素，可以使一个项目进入传播中断核实的最后阶段。
