02946nas a2200433   4500000000100000008004100001653001200042653002200054653003900076653001500115653002800130653001800158653002400176653003500200653001100235653001400246100001500260700001600275700001100291700001300302700002100315700001500336700001700351700001400368700001600382700001500398700001700413700001800430700002100448700001200469700001400481700001500495700001400510700001600524700001600540245013000556520181200686022001402498       2018                            d10aBolivia10aDeworming program10aNeglected tropical diseases (NTDs)10aPrevalence10apreventive chemotherapy10aprotozoonosis10aschool-age children10aSoil-transmitted helminthiases10aSurvey10atapeworms1 aSpinicci M1 aMacchioni F1 aRojo D1 aGamboa H1 aLiz Villagrán A1 aVallejos Y1 aStrohmeyer M1 aRoselli M1 aGabrielli S1 aCancrini G1 aMonasterio J1 aCastellanos P1 aAdolfo Paredes G1 aMaury S1 aZárate A1 aRocabado R1 aOlliaro P1 aMontresor A1 aBartoloni A00aScaling down a deworming program among school-age children after a thirty-year successful intervention in the Bolivian Chaco.3 a<p><strong>OBJECTIVE: </strong>Preventive chemotherapy is the WHO-recommended control method for soil-transmitted helminthiases. In the Bolivian Chaco, 6-monthly single-dose mebendazole delivery to school-age children achieved a dramatic decrease in soil-transmitted helminthiases prevalence between 1987 and 2013. Consequently, in September 2016, preventive chemotherapy delivery was interrupted in 9 rural communities. In compliance with WHO recommendations, we intensified surveillance to monitor soil-transmitted helminthiases prevalence and detect potential changes that would require interventions.</p>

<p><strong>METHODS: </strong>We conducted two cross-sectional parasitology surveys 12 months apart (September 2016 - 2017) amongst school-age children living in the communities where preventive chemotherapy delivery had been halted. Study design, methods of sampling and sample analysis technique (direct microscopy, Kato-Katz technique) followed WHO recommendations, aiming to obtain data representative of the Bolivian Chaco ecological zone.</p>

<p><strong>RESULTS: </strong>We collected 426 samples in 2016 and 520 in 2017. Soil-transmitted helminthiases prevalence was unremarkable: 0.7% (95%CI 0-1.5%) in 2016 and 0.8% (0-1.5%) in 2017. Conversely, the prevalence of tapeworms (13% in 2016, 12% in 2017) and intestinal protozoan infections (81% in 2016 and 75% in 2017) continued to be high.</p>

<p><strong>CONCLUSIONS: </strong>Our findings support the role of preventive chemotherapy in reducing soil-transmitted helminthiases transmission, as otherwise poor hygienic and health conditions persist in the Bolivian Chaco. A national survey, involving areas from all the ecological zones of Bolivia, is now warranted. This article is protected by copyright. All rights reserved.</p>
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