Field evaluation of a 0.005% fipronil bait, orally administered to Rhombomys opimus, for control of fleas (Siphonaptera: Pulicidae) and phlebotomine sand flies (Diptera: Psychodidae) in the Central Asian Republic of Kazakhstan

Abstract

Plague (Yersinia pestis) and zoonotic cutaneous leishmaniasis (Leishmania major) are two rodent-associated diseases which are vectored by fleas and phlebotomine sand flies, respectively. In Central Asia, the great gerbil (Rhombomys opimus) serves as the primary reservoir for both diseases in most natural foci. The systemic insecticide fipronil has been previously shown to be highly effective in controlling fleas and sand flies. However, the impact of a fipronil-based rodent bait, on flea and sand fly abundance, has never been reported in Central Asia. A field trial was conducted in southeastern Kazakhstan to evaluate the efficacy of a 0.005% fipronil bait, applied to gerbil burrows for oral uptake, in reducing Xenopsylla spp. flea and Phlebotomus spp. sand fly abundance. All active gerbil burrows within the treated area were presented with ~120 g of 0.005% fipronil grain bait twice during late spring/early summer (June 16, June 21). In total, 120 occupied and 14 visited gerbil colonies were surveyed and treated, and the resulting application rate was minimal (~0.006 mg fipronil/m2). The bait resulted in 100% reduction in Xenopsylla spp. flea abundance at 80-days post-treatment. Gravid sand flies were reduced ~72% and 100% during treatment and at week-3 post-treatment, respectively. However, noticeable sand fly reduction did not occur after week-3 and results suggest environmental factors also influenced abundance significantly. In conclusion, fipronil bait, applied in southeastern Kazakhstan, has the potential to reduce or potentially eliminate Xenopsylla spp. fleas if applied at least every 80-days, but may need to be applied at higher frequency to significantly reduce the oviposition rate of Phlebotomus spp. sand flies. Fipronil-based bait may provide a means of controlling blood-feeding vectors, subsequently reducing disease risk, in Central Asia and other affected regions globally.

Estimating the efficacy of community-wide use of systemic insecticides in dogs to control zoonotic visceral leishmaniasis: A modelling study in a Brazilian scenario

“…Oral treatments (e.g. treated baits [ 27 ] or chewable tablets [ 28 , 29 ]) could be used to significantly reduce dog handling.…”

Visceral leishmaniasis on the Indian Subcontinent: Efficacy of fipronil-based cattle treatment in controlling sand fly populations is dependent on specific aspects of sand fly ecology

“…Since simulation results suggest that larval mortality has greater impact on P. argentipes populations than adult mortality, fipronil application would be more efficacious in areas with greater FOF. Several studies have indicated phlebotomine sand fly sensitivity to fipronil [26,[29][30][31][32], with P. argentipes larvae being particularly vulnerable [32]. Poché et al recorded 100% larval mortality up to 21-days post treatment at all fipronil concentrations they administered to cattle (Bos taurus) [32].…”

“…Cattle are often heavily infested with ectoparasites such as ticks in India, which in addition to leading to disease transmission causes extensive harm to livestock production and health [70]. Prior research indicates that oral fipronil can remove ticks [23] and fleas [24,26] infesting rodents under laboratory and field conditions. Poché et al [32] noted a significant decrease in tick numbers on cattle treated orally with a single dose of 0.5 mg/kg fipronil under pen conditions.…”

“…Fipronil acts by disrupting the central nervous system of insects by interfering with the passage of chloride ions through the GABA-regulated chloride channels (Rhone-Poulenc Ag Company 1996, now known as Bayer Crop Science). It has been shown to be highly effective as an oral endectocide against several disease vectors such as fleas [23][24][25][26], ticks [23], mosquitoes [27,28], and P. papatasi [29,30], Phlebotomus mongolensis [26] and P. argentipes [31,32] sand flies. In terms of the efficacy of fipronil against sand flies, when administered to a host orally, it permeates in the blood and is excreted in the feces [33], allowing for control of both blood-feeding adult and fecal-feeding larval sand flies.…”

A spatial ecology study in a high‐diversity host community to understand blood‐feeding behaviour in Phlebotomus sandfly vectors of Leishmania

“…Preventive treatments with other insecticides including fipronil and cypermethrin were not associated with reduced feeding, and neither product used alone is indicated against sandflies and leishmaniasis control in dogs. However, in a recent field study, fipronil baits given to Rhombomys opimus rodents, reservoirs of L. major in central Asia, significantly reduced gravid female abundance (Poché et al ., ), and cypermethrin was found to be effective in controlling L. longipalpis sandflies when sprayed on the walls of human residences in Brazil (Barata et al ., ). It should be stressed, however, that none of the commercially available insecticide treatments against sandflies have repellent activity that is 100% effective, and studies in dogs suggest that sandfly biting frequencies and feeding preferences may vary among individuals of the same species (Risueño et al ., 2018, 2019).…”