Using the ectocide Fluralaner administered per os to Rattus rattus to control the flea Xenopsylla cheopis, vector of Yersinia pestis in Madagascar: the Ectopeste project

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Raharimalala, Kolohina | Zela, Lamidi | Harimalala, Mireille | Rahelinirina, Soanandrasana | Pooda, Sié Hermann | Dobigny, Gauthier | Tokiniaina, Marie Lucienne | Rajerison, Minoarisoa | Mouline, Karine

Edité par CCSD -

International audience. In Madagascar, plague remains a major public health concern. The causative agent (bacterium Yersinia pestis) is mainly vectored by Xenopsylla cheopis, a flea commonly associated to black rats, Rattus rattus, that play a central role in plague eco-epidemiology. Fleas are becoming resistant to the molecules routinely used for their control, enhancing the need of alternative strategy for disease control.The EctoPeste project aims at exploring an innovative approach to control X. cheopis using fluralaner administered per os for a systemic toxic effect on blood-feeding fleas. Fluralaner is effective for up to three months against pet fleas. Its mode of action being different from other insecticides, this would help managing the flea resistance issue. Fluralaner in fleas and rodent droppings would amplify deleterious effect at population level. Per os administration would enable focused distribution to control for environmental toxicity.We will characterize insecticidal efficacy and duration of fluralaner treatments administered per os to wild R. rattus on laboratory-reared X. cheopis. Colonies of fleas susceptible and resistant to insecticides will be fed on control and fluralaner-treated rodents (6 per arm) during direct skin-feeding experiments at different times post-treatment (2 days to 4 months). Blood fed fleas’ mortalities will be followedup. Rodent feces will be analyzed for fluralaner concentrations for proxy-characterization of lethal concentrations provoking 50 and 90% flea mortalities (LC50 and LC90).Ectopeste experiments will start in May 2024, therefore, we expect to present the following results: (i) the induced mortalities of blood-fed fleas on treated rodents for each time point post-treatment (ii) the treatment efficacy duration (iii) the fluralaner concentration vs. induced mortalities relationship to determine LC50 and LC90 values.Our results will be discussed on the light of the approach efficiency in different contexts of Madagascar, especially urban ones, and potential community-based interventions.

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