Inhibition and Prevention Efficacy against Mosquito Bloodsucking and Dirofilaria immitis Infection by Administration of Topical Insecticide

Abstract

Inhibition and prevention of mosquito bloodsucking by a topical insecticide, and the consequent infection of Dirofilaria immitis were evaluated using a product containing 10% w/w imidacloprid plus 50% w/w permethrin (I-P solution). Nine healthy beagle dogs divided in three groups of 3 dogs each were administered I-P solution on day 3 (group 1), day 36 (group 2) and not administered (group 3 as a control) before starting the experimental infection. The results showed that the mosquito bloodsucking rate was significantly lower, 12.1% in group 1 (p<0.05) and 11.1% in group 2 (p<0.05), than the 40.6% in group 3, meaning that the inhibition rates in groups 1 and 2 against group 3 were 70.2% and 72.7%. The infection rate of experimental D. immitis infection was 33% in group 1, 33% in group 2 and 100% in group 3, meaning that the prevention rates in groups 1 and 2 against group 3 were 67% and 67%. KEY WORDS: canine, Dirofilaria immitis infection, mosquito bloodsucking, topical insecticide. A spot-type insecticide solution containing both imida-cloprid and permethrin (I-P solution) is expected to show, not only an insecticidal but also a bloodsucking repellent efficacies against mosquito biting, consequently, preventing Dirofilaria immitis infection. Only a few reports, however, have studied on the bloodsucking inhibitory efficacy of imi-dacloprid and permethrin against ticks and fleas [1, 4-6, 8], and mosquitoes [1, 7]. This study was conducted to assess the inhibitory efficacy of I-P solution against bloodsucking by mosquitoes and the preventive efficacy to D. immitis infection by an experimental infection procedure. MATERIALS AND METHODS Dogs and experimental groups: Nine healthy female bea-gles were obtained commercially (Nihon Nousan Kogyo Co., Ltd., Tokyo)(weight between 7 and 11 kg, age 9 months) and confirmed to be free of D. immitis infection by the Knott test for microfilaria and a commercial antigen-detecting ELISA kit for adult worms. They were also examined by physical, hematological, blood chemistry and fecal examinations, and confirmed as normal. They were then vaccinated with a commercial mixed vaccine for dog use, housed together in a single kennel with open windows, and fed commercial dog food with free access to clean water throughout the experimental period from June 2006 to Janu-ary 2007, at the laboratory animal facility (School of Veterinary Medicine, Yamaguchi University, Yamaguchi, Japan). Groups 1 and 2 were administered I-P solution on day 3 and day 36 before the experimental D. immitis infection, respectively , and group 3 served as a control of the experimental infection without administration of I-P solution. I-P solution: The solution contains a combination of 10% imidacloprid (100 mg/ml) and 50% permethrin (500 mg/ml) (Fortreon TM , Bayer Yakuhin Co., Ltd., Tokyo) and the standard dose is to drop 0.1 ml/kg of the solution on the inter-scapular portion of the back. According to the package insertion, the solution penetrates the sebum and spreads over the skin surface throughout the body wi...

Inability of Dirofilaria immitis infective larvae from mosquitoes fed on blood from microfilaremic dogs during low-dose and short-treatment regimens of doxycycline and ivermectin to complete normal development in heartworm naïve dogs

“…In addition, this approach includes vector mosquito control using conventional methods such as insecticide application, biological control, drainage of standing water and direct treatment of animals, particularly dogs, by topical application of repellent ectoparasiticides to repel and kill infected or uninfected adult mosquitoes before biting and transmission of mf to mosquitoes or L 3 to dogs occur [21,22]. For some time, it has been known that topical administration of insecticides is effective in reducing vector mosquito populations [25][26][27][28][29][30][31][32][33][34][35][36]. It has only recently been shown that oral administration of some isoxazalines has a similar effect [23] (in this issue) [24].…”

Shifting the paradigm in Dirofilaria immitis prevention: blocking transmission from mosquitoes to dogs using repellents/insecticides and macrocyclic lactone prevention as part of a multimodal approach

“…To our knowledge, the influence of a topical repellent (imidacloprid-permethrin, IP) in the prevention of heartworm transmission has been assessed previously only once [ 15 ]. In that experiment, however, the methodology was completely different: there were three dogs per group compared with eight in the present study, the experimental infection of the control untreated dogs (1–4 worms/dog) was lower than the threshold required by FDA (≥5 worms/dog), and the animals were treated with the product 3 or 36 days prior to exposure to D. immitis -infected mosquitoes.…”

“…Several studies have reported varying levels of success with the use of topically applied products for repelling and/or killing several different species of mosquitoes [ 11 – 13 ]. One study assessed the infection of dogs and cats by West Nile virus– infected mosquitoes [ 14 ], but only one of these studies included mosquitoes or animals infected with D. immitis [ 15 ]. Encouraged by the high level of effectiveness of one of these products (Vectra® 3D, dinotefuran-permethrin-pyriproxyfen, DPP; Ceva Animal Health) against Aedes aegypti [ 16 ] and Culex pipiens [ 17 ], we investigated the role of DPP in blocking heartworm parasite transmission in dogs in two studies.…”

Cloning and overexpression of transferrin gene from cypermethrin-resistant Culex pipiens pallens

“…Fighting these diseases takes many efforts including pesticide research, vaccine development, and mosquito control (N'Guessan et al 2010;Hayasaki and Saeki 2009;Bonin et al 2009;Jambulingam et al 2008). Insecticides play a central role in controlling mosquitoes.…”