Field assessment of insecticide dusting and bait station treatment impact against rodent flea and house flea species in the Madagascar plague context

Abstract

Bubonic is the most prevalent plague form in Madagascar. Indoor ground application of insecticide dust is the conventional method used to control potentially infected rodent fleas that transmit the plague bacterium from rodents to humans. The use of bait stations is an alternative approach for vector control during plague epidemics, as well as a preventive control method during non-epidemic seasons. Bait stations have many advantages, principally by reducing the amount of insecticide used, lowering the cost of the treatment and minimizing insecticide exposure in the environment. A previous study reported promising results on controlling simultaneously the reservoir and vectors, when slow-acting rodenticide was incorporated in bait stations called “Boîtes de Kartman”. However, little evidence of an effective control of the fleas prior to the elimination of rodents was found. In this study, we evaluated bait stations containing insecticide powder and non-toxic attractive rodent bait for their potential to control rat fleas. Its efficacy was compared to the standard method. The impact of both methods on indoor and outdoor rodent fleas, as well as the human household flea Pulex irritans were analyzed at different time points after treatments. Bait stations did not cause any significant immediate or delayed reduction of rat fleas and increasing the number of operational bait stations per household did not significantly improve their efficacy. Insecticide ground dusting appeared to be the most efficient method to control indoor rat fleas. Both methods appeared to have little impact on the density of outdoor rat fleas and human fleas. These results demonstrate limited effectiveness for bait stations and encourage the maintenance of insecticide dusting as a first-line control strategy in case of epidemic emergence of plague, when immediate effect on rodent fleas is needed. Recommendations are given to improve the efficacy of the bait station method.

Poor vector competence of the human flea, Pulex irritans, to transmit Yersinia pestis

“…However, the so-called human flea associated with human dwellings in plague-endemic areas appears to have a high host preference for humans. In Madagascar, P. irritans has rarely been recovered from rodents captured inside houses, although it is the most abundant flea species sampled with light traps [ 35 , 59 ]. Blood meal analyses conducted in Uganda and the Democratic Republic of Congo also revealed that P. irritans preferred human hosts [ 60 ].…”

A Prototype Insecticide Applicator and Quality Control Monitoring for Plague Management on Prairie Dog Colonies

“…The air duster may also be an effective tool when used for vector control applications in other wildlife species (WHO 2006). The California ground squirrel (Otospermophilus beecheyi; Davis et al 2002, Hubbart et al 2011, great gerbil (Rhombomys opimus; Reijniers et al 2014), and numerous rodent species in Madagascar (Miarinjara et al 2019) are known to carry plague infected fleas, which may be controlled with applications of dust. Furthermore, bartonellosis, (Gutiérrez et al 2015) and tularemia (Roth et al 2018) are vector-borne diseases that are common to numerous wildlife species.…”

“…We compared the amount (g) of dust dispensed/burrow and duster operation time between year of application, type of equipment used, and individual duster units using pairwise t ‐tests with p ‐values adjusted for multiple tests by the Dunn‐Sidak procedure (Sokal and Rohlf 1995). We used the R statistical base package for our analyses (v3.2.3, R Development Core Team 2015).…”

Pratiques de protection des cultures en agroécosystèmes tropicaux et risques de maladies humaines et animales d’origine bactérienne

“…La lutte létale contre ces nuisibles doit aussi tenir compte du risque de transmission supérieur pour la peste (ou le typhus) que pour les zoonoses virales, car étant le fait de puces qui, en quittant les cadavres, recherchent activement d'autres hôtes (Miarinjara et al, 2019). Cela s'ajoute au risque sanitaire pour l'homme et les animaux domestiques carnivores, par la manipulation sans précaution des cadavres de rats infectés.…”