ORIGINAL RESEARCH article

Front. Malar.

Sec. Vectors

Volume 3 - 2025 | doi: 10.3389/fmala.2025.1570480

SC Johnson Guardian™ spatial repellent shows one-year efficacy against wild pyrethroid resistant Anopheles arabiensis, with similar blood-feeding inhibition efficacy to Mosquito Shield™ in a Tanzanian experimental hut trial

Provisionally accepted
Johnson  Kyeba SwaiJohnson Kyeba Swai1,2,3*Watson  Samuel NtabalibaWatson Samuel Ntabaliba1Emmanuel  MbubaEmmanuel Mbuba1,2,3Hassan  Ahamad NgoyaniHassan Ahamad Ngoyani1Noely  Otto MakungwaNoely Otto Makungwa1Antony  Pius MsekaAntony Pius Mseka1John  BradleyJohn Bradley4Madeleine  Rose ChuraMadeleine Rose Chura5Thomas  Michael MascariThomas Michael Mascari5Sarah  MooreSarah Moore1,2,3,6
  • 1Ifakara Health Institute, Ifakara, Tanzania
  • 2Swiss Tropical and Public Health Institute, Basel, Switzerland
  • 3University of Basel, Basel, Switzerland
  • 4London School of Hygiene and Tropical Medicine, University of London, London, London, United Kingdom
  • 5S. C. Johnson & Son, Inc., Racine, Wisconsin, United States
  • 6School of Life Sciences and Bioengineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania

The final, formatted version of the article will be published soon.

Background: Spatial repellents (SR) that passively emanate airborne concentrations of an active ingredient within a space disrupt mosquito behaviors to reduce human-vector contact. A clinical trial of SC Johnson’s Mosquito Shield™ (Mosquito Shield) demonstrated a 33% protective efficacy against malaria in Kenya. Mosquito Shield lasts for one month, but a longer duration product is needed for malaria control programs. SC Johnson’s Guardian™ (Guardian), is designed to provide longer continuous protection from disease-transmitting mosquitoes. Methods: we conducted experimental hut trials to i) evaluate the efficacy of Guardian over 12-months (between May 2022 and May 2023) and ii) assess the potential public health utility of Guardian by comparing it to Mosquito Shield over one month (midway through the Guardian evaluation) in November 2022) against wild pyrethroid resistant malaria vector mosquitoes. The primary endpoint was the number of blood-fed An. arabiensis, while secondary endpoints were proportion of An. arabiensis dead at 24-hours and proportion blood-fed. For Guardian, the number of mosquito landings was also evaluated by human landing catch, a method routinely used in community or implementation studies. Results: Over 12 months continuous use, Guardian reduced numbers of An. arabiensis blood-feeding by 82.7% (95% Confidence Interval (78.5 – 86.1)) and landing by 65.1% (59.4 – 70.0). Guardian also induced 20.1% mortality (18.4 – 21.8). Guardian was found to be superior to Mosquito Shield in reducing the number of blood-fed An. arabiensis with similar proportions blood-fed and dead at 24-hours. Conclusion: Guardian was effective in reducing blood-feeding and landing of wild pyrethroid resistant malaria vectors for 12-months and shows superior protective efficacy to Mosquito Shield in reducing the overall number of blood-feeding mosquitoes. Experimental hut studies are suitable for comparative evaluations of new spatial repellent products because they precisely estimate entomological endpoints elicited by spatial repellents known to significantly impact vectorial capacity and disease transmission.

Keywords: long lasting spatial emanators, Transfluthrin based spatial emanators, SC Johnson Guardian, SC Johnson Mosquito Shield, Entomological efficacy, comparative evaluation, Pyrethroid resistant Anopheles

Received: 03 Feb 2025; Accepted: 26 May 2025.

Copyright: © 2025 Swai, Ntabaliba, Mbuba, Ngoyani, Makungwa, Pius Mseka, Bradley, Chura, Mascari and Moore. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Johnson Kyeba Swai, Ifakara Health Institute, Ifakara, Tanzania

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