Background

Mass drug administration (MDA) of ivermectin has become the main intervention to control onchocerciasis or “river blindness”. In Togo, after many years of MDA, Onchocerca volvulus infection has declined dramatically, and elimination appears achievable, but in certain river basins the current situation remains unknown. We have conducted parasitological, serological, ophthalmological, and entomological assessments in northern and central Togo within the river basins of Ôti, Kéran and Mô.

Methodology/Principal findings

Examinations were completed in 1,455 participants from 11 onchocerciasis sentinel villages, and O. volvulus transmission by Simulium damnosum sensu lato (s.l.) was evaluated. In children (aged 1–10 years), the prevalence of microfilariae (Mf) was 2.3% and in adults it ranged from 5.1 to 13.3%. Positive IgG4 responses to O. volvulus adult (crude) worm antigen (OvAg) and the recombinant Ov16 antigen were in all-ages 48.7% and 34.4%, and 29.1% and 14.9% in children, respectively. In the river basin villages of Kéran, Mô and Ôti, the IgG4 seroprevalences to OvAg in children were 51.7%, 23.5% and 12.7%, respectively, and to the Ov16 antigen 33.3% (Kéran) and 5.2% (Ôti). Onchocerciasis ocular lesions (punctate keratitis, evolving iridocyclitis and chorioretinitis) were observed in children and young adults. O. volvulus-specific DNA (Ov150) was detected by poolscreen in vector samples collected from Tchitchira/Kéran(22.8%), Bouzalo/Mô(11.3%), Baghan/Mô(2.9%) and Pancerys/Ôti(4.9%); prevalences of O. volvulus infection in S. damnosum s.l. were, respectively, 1%, 0.5%, 0.1% and 0.2%.

Conclusions/Significance

In the northern and central river basins in Togo, interruption of O. volvulus transmission has not yet been attained. Patent O. volvulus infections, positive antibody responses, progressive ocular onchocerciasis were diagnosed, and parasite transmission by S. damnosum s.l. occurred close to the survey locations. Future interventions may require approaches selectively targeted to non-complying endemic populations, to the seasonality of parasite transmission and national onchocerciasis control programs should harmonize cross-border MDA as a coordinated intervention.

中文翻译：

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经过数十年的丹参总皂甙sl载体控制和伊维菌素的大规模药物管理后，多哥北部和中部的盘尾丝虫感染和血清流行病，眼盘尾丝虫病和寄生虫传播

背景

伊维菌素的大规模药物管理（MDA）已成为控制盘尾丝虫病或“河盲症”的主要干预措施。在多哥，经过多年的MDA处理后，圆盘Onchocerca volvulus感染已大大减少，而且看来可以实现消除，但是在某些流域，目前的情况仍然未知。我们在Ôti，Kéran和Mô流域的多哥北部和中部进行了寄生虫学，血清学，眼科和昆虫学评估。

方法/主要发现

来自11个盘尾丝虫病定点村庄和O的1,455名参与者完成了考试。评价了由白僵菌（Simulium damnosum sensu lato，sl）引起的肠扭转传播。在儿童（1至10岁）中，微丝aria病（Mf）的患病率为2.3％，而在成年人中，其患病率为5.1％至13.3％。IgG4对O的阳性反应。肠扭转成人（粗）蠕虫抗原（OvAg）和重组Ov16抗原在所有年龄段的儿童中分别占48.7％和34.4％，以及29.1％和14.9％。在Kéran，Mô和Ôti的流域村庄，儿童中OvAg的IgG4血清阳性率分别为51.7％，23.5％和12.7％，Ov16抗原的IgG4血清阳性率分别为33.3％（Kéran）和5.2％（Ôti）。在儿童和年轻人中发现了盘尾丝虫病眼部病变（点状角膜炎，虹膜睫状体炎和脉络膜视网膜炎）。Ø。通过池筛选在从Tchitchira /Kéran（22.8％），Bouzalo /Mô（11.3％），Baghan /Mô（2.9％）和Pancerys /Ôti（4.9％）收集的载体样品中检测到肠扭转特异性DNA（Ov150）；O的患病率。肠扭转感染小号。damnosum sl分别为1％，0.5％，0.1％和0.2％。

结论/意义

在多哥的北部和中部流域，O中断。肠息肉的传播尚未实现。专利Ø。诊断为肠扭转感染，抗体反应阳性，进行性眼部盘尾丝虫病，以及由S引起的寄生虫传播。damnosum sl发生在靠近调查地点的地方。未来的干预措施可能需要选择性地针对不符合标准的地方性人群，寄生虫传播的季节性以及国家盘尾丝虫病控制计划应采用跨界MDA作为协调干预措施。