Laboratory and field evaluation of rodent bait treated with fipronil for feed through and systemic control of Phlebotomus papatasi.

The sand fly Phlebotomus papatasi is the main vector of Leishmania major, etiologic agent of zoonotic cutaneous leishmaniasis (ZCL), which is endemic in North Africa, the Middle East, and Asia. In North Africa, Meriones shawi is one of the two main reservoir hosts of L. major. P. papatasi populations are maintained in borrowing rodents such as M. shawi. Three fipronil-treated rodent baits were evaluated for systemic and feed through insecticidal activity against P. papatasi feeding on M. shawi. Through blood feeding bioassays, mortality rates of females P. papatasi increased with the concentration of fipronil in the rodent bait varying from 0.001% to 0.005%. In the laboratory, more than 90.0% of P. papatasi were killed within 48h after blood feeding on the desert's jirds, M. shawi, treated up to 29 days prior with a single application of fipronil at a concentration of 0.001%, 0.0025% and 0.005%. Through larval bioassays, mortality rates of larvae that have fed on faeces of treated bait for M. shawi increase with the concentrations of fipronil. Faeces of orally-treated Meriones were significantly toxic to larvae for 5 weeks with a concentration of 0.005%. In the field, application of treated bait resulted in 80.0% reduction in the populations of P. papatasi up to 6 weeks after a single application of fipronil at a concentration of 0.005%. This is the first study to demonstrate field efficacy of fipronil-treated rodent baits for P. papatasi control and the first study to evaluate this approach in M. shawi, a principal ZCL reservoir host. These results suggest that fipronil-treated rodent baits can be used to effectively reduce the populations of P. papatasi associated with M. shawi in ZCL endemic areas.

[Laboratory and field evaluation of an imidacloprid treated rodent oral bait for a systemic control of Phlebotomus papatasi Scopoli, 1786 (Dipetra: Psychodidae)]. / Évaluation au laboratoire et sur le terrain de l'imidaclopride sous forme d'appâts pour les rongeurs afin de contrôler les populations de Phlebotomus papatasi Scopoli, 1786 (Dipetra: Psychodidae).

The objective of this study was to evaluate the systemic insecticidal activity of an imidacloprid-treated rodent oral bait, against Phlebotomus papatasi Scopoli, 1786 vector of Leishmania major Yakimoff & Schokhor, 1914 (Kinetoplastida: Trypanosomatidae), etiologic agent of zoonotic cutaneous leishmaniasis (ZCL). Shaw's gerbil Meriones shawi Duvernoy, 1842 (Rodentia, Gerbillidae) were treated with imidacloprid-treated bait (0.05%). In the laboratory, effects on adult and larval of Phlebotomus papatasi fed on treated M. shawi and on its faeces were studied. The effectiveness of this approach was tested under field conditions. In the laboratory, 100% of P. papatasi were killed within 24 hours after blood feeding on Meriones shawi treated up to four weeks prior with a single application of imidacloprid (0.05%) bait. In addition, none of the P. papatasi larvae that consumed feces from M. shawi treated with the imidacloprid bait survived to pupation. In the field, application of the imidacloprid bait resulted in a 90% reduction in the P. papatasi population up to four weeks prior with a single application of imidacloprid (0.05%) bait. This is the first study to demonstrate field efficacy of insecticide-treated rodent baits for P. papatasi control and the first study to evaluate this approach in M. shawi, a principal ZCL reservoir host. These results suggest that insecticide-treated rodent baits could be used to effectively reduce the populations of P. papatasi associated with M. shawi in ZCL endemic areas.