Triple-drug treatment is effective for lymphatic filariasis microfilaria clearance in Samoa

Graves, Patricia M., Sheridan, Sarah, Scott, Jessica, Sam, Filipina Amosa Lei, Naseri, Take, Thomsen, Robert, King, Christopher L., and Lau, Colleen L. (2021) Triple-drug treatment is effective for lymphatic filariasis microfilaria clearance in Samoa. Tropical Medicine and Infectious Disease, 6 (2). 44.

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Following the first triple-drug mass drug administration (MDA) for lymphatic filariasis in Samoa in 2018, unexpected persistence of microfilaria (Mf) positivity in 18 (15%) of 121 antigen-positive persons was observed in a nationwide household survey 1–2 months later. Of the 18 Mf positive persons, 14 reported taking the MDA, raising concerns about MDA efficacy. In 2019, 5–6 months after the 2018 survey, a monitored treatment study was done to evaluate directly observed weight-based treatment in these Mf positive individuals. Mf presence and density were assessed before and 7 days after treatment, using 1 mL membrane filtered venous blood, and 60 uL thick blood films on slides prepared from venous or fingerprick blood. All 14 participants were still Mf positive on filters from venous blood pre-treatment samples, but two were negative by slide made from the same samples. Mf were cleared completely by day 7 in 12 of 13 participants followed up, and by day 30 in the remaining participant. Filtered blood using EDTA samples (to reduce clumping of Mf) is preferred over slides alone for improving the likelihood of detecting Mf and estimating their density. The triple-drug MDA strategy was effective at clearing Mf when given and taken at the correct dose.

Item ID: 70697
Item Type: Article (Research - C1)
ISSN: 2414-6366
Keywords: Albendazole, DEC, Ivermectin, Lymphatic filariasis, Microfilaria, Samoa
Copyright Information: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (
Funders: National Health and Medical Research Council (NHMRC)
Date Deposited: 19 Apr 2022 04:07
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