Palatability and toxicity of fipronil as a systemic insecticide in a bromadiolone rodenticide bait for rat and flea control

Abstract

Vector control in plague-infested areas requires a simultaneous killing of rodents and their fleas. We investigated the efficacy of a combination of a systemic insecticide, fipronil, in a rodenticide bait formulation under laboratory conditions. Four different concentrations of fipronil (0.05%, 0.005%, 0.0005% with acetone as a solvent, and 0.05% with propylene glycol as a solvent) and two controls (solvents only) were combined with the rodenticide bait (crushed organically grown wheat with 0.005% bromadiolone). Each concentration was offered together with an untreated non-poisonous challenge bait to 10 singly caged Rattus rattus L., each with 100 rat fleas Xenopsylla cheopis Rothschild (Siphonaptera: Pulicidae) in the nest. Treated bait consumption was relatively low and an unsatisfactory rat mortality of around 50% only was obtained in all tests. The palatability of the bait, however, was not affected by the fipronil concentration. Even at the lowest fipronil concentration, average flea mortality was still above 95%, and doses of more than I mg fipronil per kg rat body weight gave a nearly complete kill of fleas. Fipronil can be highly effective as a systemic insecticide to for flea control, provided that a more attractive bait base for roof rats is used.

Environmental influence on urban rodent bait consumption

“…The overall mean bait consumption was very low and this was probably due to the inadequate palatability of the paraffin bait blocks with rodenticide bromadiolone, as already noted by Leirs et al (2001). However, despite the Fig.…”

Plague risk in vulnerable community: assessment of Xenopsylla cheopis susceptibility to insecticides in Malagasy prisons

“…For highly insecticide resistant population, such as fleas from Antanimora, other approaches on flea control must be taken into account. Systemic insecticide might be a promising alternative to target on host fleas [ 19 – 21 ]. Systemic insecticides are toxic for fleas when ingested by rodents, which make them more accurate on targeting rodents’ fleas than insecticide dusting.…”

“…Besides, its chemical structure is different from insecticide recommended for flea control in plague foci, then can be efficient in localities where cross resistance is suspected among vectors. Besides, its systemic action is significant at low concentration [ 19 ]. Efficiency of systemic insecticides was tested on laboratory and feasibility on field was evaluated [ 19 , 22 – 26 ].…”

Preliminary Survey of Ectoparasites and Associated Pathogens from Norway Rats in New York City

“…Based on their medical importance, the collection of >6,500 individual ectoparasites from 133 Norway rats critically highlights the need for rodent control programs that also address ectoparasites. Previously, rodenticide baits containing insecticides have been investigated (Leirs et al 2001), and might act to reduce the incidence of accidental feeding by ectoparasites when rodent hosts are killed. However, further research is needed to identify compounds that, when added to cereal-based rodenticide grain baits, will not significantly reduce palatability to rodents (Borchert et al 2010).…”