Xenopsylla cheopis (Siphonaptera: Pulicidae) susceptibility to Deltamethrin in Madagascar.

Sebastien Boyer,Adélaïde Miarinjara,Nohal Elissa,Érika Martins Braga

doi:10.1371/journal.pone.0111998

Sebastien Boyer, Adélaïde Miarinjara + Show 2 more

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https://doi.org/10.1371/journal.pone.0111998

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Abstract

The incidence of bubonic plague in Madagascar is high. This study reports the susceptibility of 32 different populations of a vector, the flea Xenopsylla cheopis (Siphonaptera: Pulicidae), to the insecticide Deltamethrin. Despite the use of Deltamethrin against fleas, plague epidemics have re-emerged in Madagascar. The majority of the study sites were located in the Malagasy highlands where most plague cases have occurred over the last 10 years. X. cheopis fleas were tested for susceptibility to Deltamethrin (0.05%): only two populations were susceptible to Deltamethrin, four populations were tolerant and 26 populations were resistant. KD50 (50% Knock-Down) and KD90 (90% Knock-Down) times were determined, and differed substantially from 9.4 to 592.4 minutes for KD50 and 10.4 min to 854.3 minutes for KD90. Susceptibility was correlated with latitude, but not with longitude, history of insecticide use nor date of sampling. Combined with the number of bubonic plague cases, our results suggest that an immediate switch to an insecticide other than Deltamethrin is required for plague vector control in Madagascar.

Highlights

IntroductionEctoparasites (including ticks and fleas) are both pests and vectors of various diseases of humans, livestock, pets, and wild animals
Ectoparasites are both pests and vectors of various diseases of humans, livestock, pets, and wild animals
X. cheopis is the main vector, the black rat is frequently parasitized by the endemic flea S. fonquerniei, and this species contributes to the circulation of Y. pestis in the rural murine population [4]

Summary

Introduction

Ectoparasites (including ticks and fleas) are both pests and vectors of various diseases of humans, livestock, pets, and wild animals. They can transmit diverse pathogens of medical and/or veterinary significance, including viruses, bacteria, protozoa, and helminthes [1]. Plague is a life-threatening infectious disease caused by the Gram-negative bacterium Yersinia pestis [6,7,8]. It primarily affects rodents, but can cause outbreaks in human populations. X. cheopis is the main vector, the black rat is frequently parasitized by the endemic flea S. fonquerniei, and this species contributes to the circulation of Y. pestis in the rural murine population [4]

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