The Experts below are selected from a list of 1362 Experts worldwide ranked by ideXlab platform
Michael K. Rust - One of the best experts on this subject based on the ideXlab platform.
-
international program to monitor Cat Flea populations for susceptibility to imidacloprid
Journal of Medical Entomology, 2018Co-Authors: Michael K. Rust, Michael W Dryden, Nancy C Hinkle, Byron L Blagburn, I Denholm, Patricia A Payne, Steven R Kopp, Martin S WilliamsonAbstract:An international team of scientists and veterinarians was assembled in 1999 to develop a monitoring program to determine the susceptibility of Cat Fleas, Ctenocephalides felis felis (Bouche) (Siphonaptera: Pulicidae), to imidacloprid. Cat Flea eggs were collected, shipped to laboratories, and tested for their susceptibility to imidacloprid. Over 3,000 C. felis populations were collected from 2002 to 2017 from 10 different countries. Of these, 66.3% were collected from Cats and 33.7% from dogs. C. f. felis populations (n = 2,200) were bioassayed by exposing Cat Flea eggs and the emerging larvae to a Diagnostic Dose (DD) of 3 ppm imidacloprid in larval rearing medium. Flea eggs hatched and developed in the untreated controls in 1,837 of the isolates (83.5%) bioassayed. Flea isolates (n = 61) that had ≥5% survival at the DD of 3 ppm were retested with a second DD of 3 ppm. None of them had ≥5% survival to the second dose of 3 ppm. Of the 1,837 valid C. felis isolates tested, there has been no evidence of a decreased susceptibility to imidacloprid over the past 17 yr. The methods outlined in this article should provide an acceptable protocol for testing many of the new active ingredients that have been registered for Cat Flea control.
-
large scale monitoring of imidacloprid susceptibility in the Cat Flea ctenocephalides felis
Medical and Veterinary Entomology, 2011Co-Authors: Michael K. Rust, Michael W Dryden, N. Mencke, D E Jacobs, Iris Schroeder, Byron L Blagburn, I Denholm, Patricia A Payne, R Bond, S WestonAbstract:Although on-animal topical treatment with compounds such as imidacloprid has revolutionized the control of the Cat Flea, Ctenocephalides felis (Bouche) (Siphonaptera: Pulicidae), the development of insecticide resistance is a continuing threat. As part of a highly co-ordinated and unprecedented resistance monitoring programme for C. felis, 1437 Flea isolates were collected by veterinary clinics in Australia, Germany, France, the U.K. and 29 states in the U.S.A. from 2002 to 2009. About 65% of the collections were made from June to October each year and 71% of the collections were from Cats. Collections of Flea eggs were sent to one of five different laboratories, where they were tested with a diagnostic dose of imidacloprid (3 p.p.m.) applied to larval Flea-rearing medium. Of the 1437 collections received, 1064 contained adequate numbers of eggs for testing. Of these isolates, untreated eggs failed to hatch in 22.7% and were not considered valid bioassays. Survival rates > 5% and development of adult Fleas (a threshold for further testing) occurred in only 22 isolates. They were re-tested with the same diagnostic dose and none produced > 5% adult emergence. Complete dose-response bioassays were performed on three of the isolates that had triggered a second test and produced slopes, intercepts and LC(50) values similar to those for existing susceptible laboratory strains. Results confirmed sustained susceptibility of C. felis to imidacloprid, despite its widespread use for over a decade.
-
advances in the control of ctenocephalides felis Cat Flea on Cats and dogs
Trends in Parasitology, 2005Co-Authors: Michael K. RustAbstract:Cat Fleas are the most important ectoparasite of Cats and dogs worldwide. During the past ten years, topical and oral appliCations of insecticides such as fipronil, imidacloprid, lufenuron and, most recently, selamectin have revolutionized Cat-Flea control. Recent studies show that these therapies eliminate the need to treat indoor and outdoor environments, and their use markedly reduces the severity and prevalence of Flea allergic dermatitis. Surveys have yet to reveal the development of insecticide resistance to these chemical compounds. Extending the longevity of these effective host-targeted therapies should be a major goal of the veterinary community.
-
review of insecticide resistance in Cat Fleas siphonaptera pulicidae
Journal of Medical Entomology, 1998Co-Authors: Robert L Bossard, Nancy C Hinkle, Michael K. RustAbstract:Insecticide resistance often is blamed for failures of insecticides to control Cat Fleas, Ctenocephalides felis (Bouche). Yet the genetics and adaptive advantage of resistance traits remain unexamined. Lethal doses of insecticides that kill 50% of the population fluctuate 7-fold within a Cat Flea strain. Many reports of Flea resistance may be attributable to variable mortality from effects of solvents, substrates, humidities, temperatures, colonization, and ages of Fleas. Resistance ratios (ratios of lethal doses of a resistant to a susceptible strain) are < 690-fold in Fleas; lower than many other arthropods. This, plus strain variability, hinders resistance detection. Relationships between resistance levels, control failures, and health threats are unclear. Insensitive acetylcholinesterase, knockdown recovery, glutathione transferase conjugation, and mixed function oxidase/cytochrome P450 are demonstrated resistance mechanisms in Cat Fleas. Ecological genetics of resistance in Cat Fleas probably involves Flea transfer among hosts, host movements, refugia, founder effects, and mortality from abiotic factors. Understanding Cat Flea resistance requires population monitoring before, during, and after insecticide treatments using conventional and rapid molecular bioassays. Sustained insecticide release devices such as Flea collars and long-lived insecticide residues for premises possibly contribute to the development of resistance. New systemic and topical insecticides, especially when given prophylactically, may act similarly. Eliminating insecticides prevents insecticide resistance but necessitates appliCation of biorational tactics incorporating mechanical, environmental, and cultural controls. Using high temperatures, low humidities, host grooming and such tactics as decreasing doses, increasing action thresholds, rotating insecticides, and leaving spatial and temporal refugia may suppress Cat Flea resistance.
-
influence of photoperiod on egg production of Cat Fleas siphonaptera pulicidae infesting Cats
Journal of Medical Entomology, 1992Co-Authors: Michael K. RustAbstract:Photoperiod affected the production of Cat Flea eggs by Cats infested with Cat Flea, Ctenocephalides felis (Bouche). Cat Flea eggs have a smooth chorion and do not adhere to the host. About 60% of fluorescing eggs placed in the pelage were recovered in collecting trays underneath the host in 2 h. An average of 87.7 eggs per Cat was laid during the last 8 h of the scotophase compared with 49.9 and 59.1 eggs during the other 8-h periods. Significant variation in the number of eggs collected daily existed among the six Cats. The activity budgets were similar for all the Cats with the maximum sleep period during the photophase. The possible adaptive advantages of synchronizing egg production with photoperiod are discussed.
Kevin R Macaluso - One of the best experts on this subject based on the ideXlab platform.
-
the complete mitochondrial genome of the Cat Flea ctenocephalides felis
Mitochondrial DNA Part B, 2020Co-Authors: Victoria I Verhoeve, Kevin R Macaluso, Mariah L Plumer, Timothy P Driscoll, Abdu F Azad, Joseph J GillespieAbstract:The Cat Flea, Ctenocephalides fells, is widely recognized as a global veterinary pest and a vector of pathogenic bacteria. We recently reported on the C. felis nuclear genome, which is characterized by over 38% protein coding gene dupliCation, extensive tRNA gene family expansion, and remarkable gene copy number variation (CNV) between individual Fleas. Herein, we describe the assembly of the C. felis mitochondrial genome, a novel resource for comparative genomics of Fleas and other insects. The order and content of mitochondrial genes is highly consistent with four previously sequenced Flea mitochondrial genomes, limiting CNV to siphonapteran nuclear genomes.
-
a chromosome level assembly of the Cat Flea genome uncovers rampant gene dupliCation and genome size plasticity
BMC Biology, 2020Co-Authors: Timothy Driscoll, Sayeedur M Rahman, Victoria I Verhoeve, Joseph J Gillespie, Spencer J Johnston, Mark L Guillotte, Kristen E Rennollbankert, Darren E Hagen, Christine G Elsik, Kevin R MacalusoAbstract:Fleas (Insecta: Siphonaptera) are small flightless parasites of birds and mammals; their blood-feeding can transmit many serious pathogens (i.e., the etiological agents of bubonic plague, endemic and murine typhus). The lack of Flea genome assemblies has hindered research, especially comparisons to other disease vectors. Accordingly, we sequenced the genome of the Cat Flea, Ctenocephalides felis, an insect with substantial human health and veterinary importance across the globe. By combining Illumina and PacBio sequencing of DNA derived from multiple inbred female Fleas with Hi-C scaffolding techniques, we generated a chromosome-level genome assembly for C. felis. Unexpectedly, our assembly revealed extensive gene dupliCation across the entire genome, exemplified by ~ 38% of protein-coding genes with two or more copies and over 4000 tRNA genes. A broad range of genome size determinations (433–551 Mb) for individual Fleas sampled across different populations supports the widespread presence of fluctuating copy number variation (CNV) in C. felis. Similarly, broad genome sizes were also calculated for individuals of Xenopsylla cheopis (Oriental rat Flea), indiCating that this remarkable “genome-in-flux” phenomenon could be a siphonapteran-wide trait. Finally, from the C. felis sequence reads, we also generated closed genomes for two novel strains of Wolbachia, one parasitic and one symbiotic, found to co-infect individual Fleas. Rampant CNV in C. felis has dire impliCations for gene-targeting pest control measures and stands to compliCate standard normalization procedures utilized in comparative transcriptomics analysis. Coupled with co-infection by novel Wolbachia endosymbionts—potential tools for blocking pathogen transmission—these oddities highlight a unique and underappreciated disease vector.
-
effect of rickettsia felis strain variation on infection transmission and fitness in the Cat Flea siphonaptera pulicidae
Journal of Medical Entomology, 2017Co-Authors: Sean P Healy, Lane D Foil, Lisa D Brown, Melena R Hagstrom, Kevin R MacalusoAbstract:Rickettsia felis is a human pathogen transmitted by the Cat Flea, Ctenocephalides felis (Bouche) (str. LSU), as well as an obligate symbiont of the parthenogenic booklouse Liposcelis bostrychophila (Badonnel) (str. LSU-Lb). The influence of genetic variability in these two strains of R. felis on host specialization and fitness and possible resulting differences on infection and transmission kinetics in C. felis is unknown. Utilizing an artificial host system, Cat Fleas were exposed to a R. felis str. LSU-Lb-infected bloodmeal and monitored for infection at 7-d intervals for 28 d. Quantitative real-time PCR was used to determine rickettsial load and infection density in newly exposed Cat Fleas, and transmission frequency between Cat Fleas. The effect of persistent R. felis infection on Cat Flea F1 progeny was also assessed. At 7 d postexposure 76.7% of the Cat Fleas successfully acquired R. felis str. LSU-Lb. In R. felis str. LSU-Lb-exposed Cat Fleas, the mean infection load (6.15 × 106), infection density (0.76), and infection prevalence (91/114) were significantly greater than R. felis str. LSU infection load (3.09 × 106), infection density (0.68), and infection prevalence (76/113). A persistent R. felis str. LSU-Lb infection was detected for 28 d in adult Cat Fleas but neither female:male ratio distortion nor vertical transmission was observed in F1 progeny. While infection kinetics differed, with higher intensity associated with R. felis str. LSU-Lb, no distinct phenotype was observed in the F1 progeny.
-
An Insight into the Sialotranscriptome of the Cat Flea, Ctenocephalides felis
2016Co-Authors: Jose ́ M. C. Ribeiro, Teresa C. F. Assumpção, Patricia H. Alvarenga, Van M. Pham, John F. Andersen, Ivo M. B. Francischetti, Kevin R MacalusoAbstract:Background: Saliva of hematophagous arthropods contains a diverse mixture of compounds that counteracts host hemostasis. Immunomodulatory and antiinflammatory components are also found in these organisms ’ saliva. Blood feeding evolved at least ten times within arthropods, providing a scenario of convergent evolution for the solution of the salivary potion. Perhaps because of immune pressure from hosts, the salivary proteins of related organisms have considerable divergence, and new protein families are often found within different genera of the same family or even among subgenera. Fleas radiated with their vertebrate hosts, including within the mammal expansion initiated 65 million years ago. Currently, only one Flea species–the rat Flea Xenopsylla cheopis–has been investigated by means of salivary transcriptome analysis to reveal salivary constituents, or sialome. We present the analysis of the sialome of Cat Flea Ctenocephaides felis. Methodology and Critical Findings: A salivary gland cDNA library from adult Fleas was randomly sequenced, assembled, and annotated. Sialomes of Cat and rat Fleas have in common the enzyme families of phosphatases (inactive), CD-39-type apyrase, adenosine deaminases, and esterases. Antigen-5 members are also common to both sialomes, as are defensins. FS-I/Cys7 and the 8-Cys families of peptides are also shared by both Fleas and are unique to these organisms. The Gly-His-rich peptide similar to holotricin was found only in the Cat Flea, as were the abundantly expressed Cys-less peptide and a novel short peptide family
-
an insight into the sialotranscriptome of the Cat Flea ctenocephalides felis
PLOS ONE, 2012Co-Authors: Jose M C Ribeiro, Patricia H. Alvarenga, Van M. Pham, John F. Andersen, Ivo M. B. Francischetti, Teresa C F Assumpcao, Kevin R MacalusoAbstract:Background: Saliva of hematophagous arthropods contains a diverse mixture of compounds that counteracts host hemostasis. Immunomodulatory and antiinflammatory components are also found in these organisms’ saliva. Blood feeding evolved at least ten times within arthropods, providing a scenario of convergent evolution for the solution of the salivary potion. Perhaps because of immune pressure from hosts, the salivary proteins of related organisms have considerable divergence, and new protein families are often found within different genera of the same family or even among subgenera. Fleas radiated with their vertebrate hosts, including within the mammal expansion initiated 65 million years ago. Currently, only one Flea species–the rat Flea Xenopsylla cheopis–has been investigated by means of salivary transcriptome analysis to reveal salivary constituents, or sialome. We present the analysis of the sialome of Cat Flea Ctenocephaides felis. Methodology and Critical Findings: A salivary gland cDNA library from adult Fleas was randomly sequenced, assembled, and annotated. Sialomes of Cat and rat Fleas have in common the enzyme families of phosphatases (inactive), CD-39-type apyrase, adenosine deaminases, and esterases. Antigen-5 members are also common to both sialomes, as are defensins. FSI/Cys7 and the 8-Cys families of peptides are also shared by both Fleas and are unique to these organisms. The Gly-His-rich peptide similar to holotricin was found only in the Cat Flea, as were the abundantly expressed Cys-less peptide and a novel short peptide family. Conclusions/Significance: Fleas, in contrast to bloodsucking Nematocera (mosquitoes, sand flies, and black flies), appear to concentrate a good portion of their sialome in small polypeptides, none of which have a known function but could act as inhibitors of hemostasis or inflammation. They are also unique in expansion of a phosphatase family that appears to be deficient of enzyme activity and has an unknown function.
Lane D Foil - One of the best experts on this subject based on the ideXlab platform.
-
effect of rickettsia felis strain variation on infection transmission and fitness in the Cat Flea siphonaptera pulicidae
Journal of Medical Entomology, 2017Co-Authors: Sean P Healy, Lane D Foil, Lisa D Brown, Melena R Hagstrom, Kevin R MacalusoAbstract:Rickettsia felis is a human pathogen transmitted by the Cat Flea, Ctenocephalides felis (Bouche) (str. LSU), as well as an obligate symbiont of the parthenogenic booklouse Liposcelis bostrychophila (Badonnel) (str. LSU-Lb). The influence of genetic variability in these two strains of R. felis on host specialization and fitness and possible resulting differences on infection and transmission kinetics in C. felis is unknown. Utilizing an artificial host system, Cat Fleas were exposed to a R. felis str. LSU-Lb-infected bloodmeal and monitored for infection at 7-d intervals for 28 d. Quantitative real-time PCR was used to determine rickettsial load and infection density in newly exposed Cat Fleas, and transmission frequency between Cat Fleas. The effect of persistent R. felis infection on Cat Flea F1 progeny was also assessed. At 7 d postexposure 76.7% of the Cat Fleas successfully acquired R. felis str. LSU-Lb. In R. felis str. LSU-Lb-exposed Cat Fleas, the mean infection load (6.15 × 106), infection density (0.76), and infection prevalence (91/114) were significantly greater than R. felis str. LSU infection load (3.09 × 106), infection density (0.68), and infection prevalence (76/113). A persistent R. felis str. LSU-Lb infection was detected for 28 d in adult Cat Fleas but neither female:male ratio distortion nor vertical transmission was observed in F1 progeny. While infection kinetics differed, with higher intensity associated with R. felis str. LSU-Lb, no distinct phenotype was observed in the F1 progeny.
-
development of microsatellites for genetic analyses and population assignment of the Cat Flea siphonaptera pulicidae
Journal of Medical Entomology, 2010Co-Authors: Claudia Husseneder, Lane D Foil, Susan P Garner, Kevin R MacalusoAbstract:Cat Fleas, Ctenocephalides felis (Bouche) (Siphonaptera: Pulicidae), are common ectoparasites of companion animals that negatively impact their hosts directly by causing dermatitis and blood loss during feeding and indirectly through the potential transmission of disease causing agents. We isolated and characterized seven novel microsatellite loci from a partial genomic library of the Cat Flea enriched for di-, tri-, and tetranucleotide repeats. We screened these loci in Cat Fleas from two laboratory colonies and one wild-caught population collected at a temporary animal shelter (Parker coliseum) in Baton Rouge, LA. Six loci were polymorphic, with two to 15 alleles per locus and an average observed heterozygosity of 0.21 across populations. Although the two laboratory Cat Flea colonies were isolated from each other for many years, they did not significantly differ in their genotypic composition. The Cat Flea population from Parker coliseum was genetically different from the laboratory colonies, but also showed high degrees of inbreeding. Multilocus genotypes of the polymorphic loci were sufficient to assign over 85% of Cat Fleas to their population of origin. Genetic markers for Flea population identity will allow further studies to examine the origins and movement of Cat Fleas with important genetic traits such as insecticide resistance or pathogen susceptibility. The use of microsatellites also could determine if there are host-specific strains of Cat Fleas and add insight into the development of the different subspecies of C. felis.
-
studies on the growth of bartonella henselae in the Cat Flea siphonaptera pulicidae
Journal of Medical Entomology, 2002Co-Authors: Jessica L Finkelstein, Tracy P Brown, Kathy L Oreilly, Jimmy Wedincamp, Lane D FoilAbstract:Two out of three pools of Cat Fleas, Ctenocephalides felis (Bouche), that were fed Bartonella henselae-positive Cat blood for 3 d and then bovine blood for 3 d, were polymerase chain reaction (PCR) positive for B. henselae. In a second experiment, three Cats were inoculated with a streptomycin-resistant strain of B. henselae. After the Cats were inoculated, caged Cat Fleas were fed on the Cats during three different periods, and then pooled and transferred to noninfected recipient Cats. In the first trial, the bacteria in the Flea feces were below level of detection when the Fleas were transferred from the infected Cats to the recipient Cat. After the Fleas had fed on the recipient Cat for 6 d, a bacteria level of 4.00 x 10(3) CFU/ mg was detected in the Flea feces. Subsequently, the bacteria level increased for 4 d and then declined. In another experiment, the bacteria level in the Flea feces was 1.80 x 10(3) CFU/mg at 2 h after collection and 3.33 x 10(2) CFU/mg at 72 h after collection. These data indiCated that this strain of B. henselae can persist in Flea feces in the environment for at least 3 d, and that B. henselae can multiply in the Cat Flea.
-
efficacy of diflubenzuron in simulated household and yard conditions against the Cat Flea ctenocephalides felis bouche siphonoptera pulicidae
Journal of Medical Entomology, 1993Co-Authors: Gregg Henderson, Lane D FoilAbstract:Diflubenzuron-treated carpet inhibited egg-to-adult development of the Cat Flea for up to 12 mo even with weekly vacuuming of the carpet. The efficacy of diflubenzuron was similar in treated soils over a 6-mo test period except in the case of treated soil that remained outside. Reduced efficacy is attributed to degradation of diflubenzuron by microorganisms and water.
Marie Varloud - One of the best experts on this subject based on the ideXlab platform.
-
synergy between dinotefuran and fipronil against the Cat Flea ctenocephalides felis improved onset of action and residual speed of kill in adult Cats
Parasites & Vectors, 2017Co-Authors: Romain Delcombel, Hamadi Karembe, Bakela Nare, Audrey Burton, Julian Liebenberg, Josephus J Fourie, Marie VarloudAbstract:The Cat Flea, Ctenocephalides felis felis (C. felis), is a cosmopolitan hematophagous ectoparasite, and is considered to be the most prevalent Flea species in both Europe and the USA. Clinical signs frequently associated with Flea bites include pruritus, dermatitis and in severe cases even pyodermatitis and alopecia. Ctenocephalides felis is also a vector for several pathogens and is an intermediate host for the cestode Dipylidium caninum. Treatment of Cats with a fast-acting pulicide, that is persistently effective in protecting the animal against re-infestation, is therefore imperative to their health. In addition, a rapid onset of activity (“speed of kill”) may also reduce the risks of disease transmission and Flea allergic dermatitis. The aim of this study was to evaluate the in vitro insecticidal activity and potential synergism between dinotefuran and fipronil against C. felis. A further aim was to evaluate the onset of activity and residual speed of kill of the combination in vivo on Cats artificially infested with C. felis. In the first study, the insecticidal activity of dinotefuran and fipronil separately and dinotefuran/fipronil (DF) in combination, at a fixed ratio (2:1), was evaluated using an in vitro coated-vial bioassay. In the second study, the onset of activity against existing Flea infestations and residual speed of kill of DF against artificial Flea infestations on Cats was assessed in vivo. Onset of activity against existing Flea infestations was assessed in terms of knock-down effect within 2 h post-treatment and onset of speed of kill assessed at 3 h, 6 h and 12 h post-treatment. Residual speed of kill was evaluated 6 h and 48 h after infestation, over a period of six weeks post-treatment. In vitro results revealed that the DF combination was synergistic and more potent against Fleas than either compound alone. The combination also proved effective when tested in vivo. Efficacy was > 97% [geometric mean (GM) and arithmetic mean (AM)] at 3 h after treatment, and ≥ 99.8% (GM and AM) at 6 h and 12 h post-treatment. At 6 h after Flea re-infestations, the efficacy of DF remained ≥ 90.8% (GM and AM) for up to 28 days, and at 42 days post-treatment persistent efficacy was still ≥ 54.3% (GM and AM). At 48 h after Flea re-infestations, DF remained almost fully effective for up to 28 days, with efficacies ≥ 99.4% (GM and AM) and was persistently ≥ 93.0% (GM and AM) effective for up to 42 days post-treatment. The combination of dinotefuran and fipronil in a single formulation exhibited strong synergistic insecticidal activity against C. felis in vitro, and also proved effective on artificially infested Cats. This activity had a rapid onset that persisted for 6 weeks against re-infestations of C. felis on Cats. The rapid curative insecticidal effect was observed as early as 3 h after treatment, and as early as 6 h after re-infestations for up to 6 weeks post-treatment. The insecticidal activity profile of DF makes it an optimal candidate for the protection of Cats against Flea infestations, and possibly also associated diseases.
-
Synergy between dinotefuran and fipronil against the Cat Flea (Ctenocephalides felis): improved onset of action and residual speed of kill in adult Cats
'Springer Science and Business Media LLC', 2017Co-Authors: Romain Delcombel, Hamadi Karembe, Bakela Nare, Audrey Burton, Julian Liebenberg, Josephus Fourie, Marie VarloudAbstract:Abstract Background The Cat Flea, Ctenocephalides felis felis (C. felis), is a cosmopolitan hematophagous ectoparasite, and is considered to be the most prevalent Flea species in both Europe and the USA. Clinical signs frequently associated with Flea bites include pruritus, dermatitis and in severe cases even pyodermatitis and alopecia. Ctenocephalides felis is also a vector for several pathogens and is an intermediate host for the cestode Dipylidium caninum. Treatment of Cats with a fast-acting pulicide, that is persistently effective in protecting the animal against re-infestation, is therefore imperative to their health. In addition, a rapid onset of activity (“speed of kill”) may also reduce the risks of disease transmission and Flea allergic dermatitis. The aim of this study was to evaluate the in vitro insecticidal activity and potential synergism between dinotefuran and fipronil against C. felis. A further aim was to evaluate the onset of activity and residual speed of kill of the combination in vivo on Cats artificially infested with C. felis. Methods In the first study, the insecticidal activity of dinotefuran and fipronil separately and dinotefuran/fipronil (DF) in combination, at a fixed ratio (2:1), was evaluated using an in vitro coated-vial bioassay. In the second study, the onset of activity against existing Flea infestations and residual speed of kill of DF against artificial Flea infestations on Cats was assessed in vivo. Onset of activity against existing Flea infestations was assessed in terms of knock-down effect within 2 h post-treatment and onset of speed of kill assessed at 3 h, 6 h and 12 h post-treatment. Residual speed of kill was evaluated 6 h and 48 h after infestation, over a period of six weeks post-treatment. Results In vitro results revealed that the DF combination was synergistic and more potent against Fleas than either compound alone. The combination also proved effective when tested in vivo. Efficacy was > 97% [geometric mean (GM) and arithmetic mean (AM)] at 3 h after treatment, and ≥ 99.8% (GM and AM) at 6 h and 12 h post-treatment. At 6 h after Flea re-infestations, the efficacy of DF remained ≥ 90.8% (GM and AM) for up to 28 days, and at 42 days post-treatment persistent efficacy was still ≥ 54.3% (GM and AM). At 48 h after Flea re-infestations, DF remained almost fully effective for up to 28 days, with efficacies ≥ 99.4% (GM and AM) and was persistently ≥ 93.0% (GM and AM) effective for up to 42 days post-treatment. Conclusions The combination of dinotefuran and fipronil in a single formulation exhibited strong synergistic insecticidal activity against C. felis in vitro, and also proved effective on artificially infested Cats. This activity had a rapid onset that persisted for 6 weeks against re-infestations of C. felis on Cats. The rapid curative insecticidal effect was observed as early as 3 h after treatment, and as early as 6 h after re-infestations for up to 6 weeks post-treatment. The insecticidal activity profile of DF makes it an optimal candidate for the protection of Cats against Flea infestations, and possibly also associated diseases
-
onset of efficacy and residual speed of kill over one month of a topical dinotefuran permethrin pyriproxyfen combination vectra 3d against the adult Cat Flea ctenocephalides felis felis on dogs
Veterinary Parasitology, 2015Co-Authors: Marie VarloudAbstract:Abstract This study was designed to assess the onset of therapeutic and residual insecticidal efficacy of a topical ectoparasiticide (Vectra®3D, DPP) on dogs over one month against the Cat Flea, Ctenocephalides felis felis. Adult dogs (n = 32, 11.0–18.7 kg) were infested with 100 adult Fleas on days −6, −2, 7, 14, 21 and 28. Based on Flea retention, the dogs were alloCated in two groups and were treated topically on day 0 with a control solution (CS) or DPP. Each group was divided in two subgroups in which live Fleas were counted by combing the dogs 2 or 6 h after treatment and at each re-infestation. The insecticidal efficacy was calculated using arithmetic and geometric means at each time point. The Flea retention rate ranged from 64.0 to 86.5% in the CS group throughout the study. Based on arithmetic means, the therapeutic efficacy was 96.4% 6 h post-treatment and residual efficacies ranged from 96.8 to 99.9% 2 h after each re-infestation. The residual speed of killing effectiveness, >96% at 2 h, persisted for one month after treatment. DPP administration was well tolerated. This study confirms that DPP starts killing Fleas within 2 h after treatment and reaches efficacy levels >95% at 6 h. We have shown that DPP kills >96.8% of Fleas for one month after treatment within 2 h after infestation.
Martin S Williamson - One of the best experts on this subject based on the ideXlab platform.
-
international program to monitor Cat Flea populations for susceptibility to imidacloprid
Journal of Medical Entomology, 2018Co-Authors: Michael K. Rust, Michael W Dryden, Nancy C Hinkle, Byron L Blagburn, I Denholm, Patricia A Payne, Steven R Kopp, Martin S WilliamsonAbstract:An international team of scientists and veterinarians was assembled in 1999 to develop a monitoring program to determine the susceptibility of Cat Fleas, Ctenocephalides felis felis (Bouche) (Siphonaptera: Pulicidae), to imidacloprid. Cat Flea eggs were collected, shipped to laboratories, and tested for their susceptibility to imidacloprid. Over 3,000 C. felis populations were collected from 2002 to 2017 from 10 different countries. Of these, 66.3% were collected from Cats and 33.7% from dogs. C. f. felis populations (n = 2,200) were bioassayed by exposing Cat Flea eggs and the emerging larvae to a Diagnostic Dose (DD) of 3 ppm imidacloprid in larval rearing medium. Flea eggs hatched and developed in the untreated controls in 1,837 of the isolates (83.5%) bioassayed. Flea isolates (n = 61) that had ≥5% survival at the DD of 3 ppm were retested with a second DD of 3 ppm. None of them had ≥5% survival to the second dose of 3 ppm. Of the 1,837 valid C. felis isolates tested, there has been no evidence of a decreased susceptibility to imidacloprid over the past 17 yr. The methods outlined in this article should provide an acceptable protocol for testing many of the new active ingredients that have been registered for Cat Flea control.
-
molecular characterisation of nicotinic acetylcholine receptor subunits from the Cat Flea ctenocephalides felis siphonaptera pulicidae
Insect Biochemistry and Molecular Biology, 2006Co-Authors: Chris Bass, Stuart J Lansdell, Neil S Millar, Iris Schroeder, Andreas Turberg, Linda M Field, Martin S WilliamsonAbstract:Abstract As part of a program to monitor the susceptibility of Cat Flea populations to the insecticide imidacloprid we have examined the Cat Flea nicotinic acetylcholine receptor, the target site protein of the neonicotinoid group of insecticides. Seven nAChR subunits (six α-type and one β-type) were identified in Cat Flea using a degenerate PCR-based strategy. Five of these were expressed in vitro by creating chimeras containing the N-terminal ligand-binding domain of the Cat Flea subunits and the C-terminal region of the Drosophila Dα2 (SAD) subunit. Two of the five chimeric subunits, Cfα1/Dα2 and Cfα3/Dα2, when co-expressed with rat β2 in Drosophila S2 cells, showed high-affinity binding of both epibatidine ( K d = 1.6 ± 0.6 and 0.13±0.06 nM, respectively), and imidacloprid ( K i = 1 4 2 ± 3 4 and 28.7±2.4 nM, respectively). It is likely therefore that Cfα1 and Cfα3 contribute to nAChR populations in vivo that are sensitive to imidacloprid. The identifiCation of Cat Flea nAChR subunits that have a high affinity for imidacloprid presents candidate genes in which to look for resistance-associated mutations if target-site resistance to imidacloprid arises in domestic pet Flea populations.
-
identifiCation of the rdl mutation in laboratory and field strains of the Cat Flea ctenocephalides felis siphonaptera pulicidae
Pest Management Science, 2004Co-Authors: Chris Bass, Iris Schroeder, Andreas Turberg, Linda M Field, Martin S WilliamsonAbstract:In many insect species, resistance to cyclodiene insecticides is caused by amino acid substitutions at a single residue (A302) within the M2 transmembrane region of the γ-aminobutyric acid (GABA) receptor sub-unit termed Rdl (resistance to dieldrin). These mutations (A302S and A302G) have also been shown to confer varying levels of cross-resistance to fipronil, a phenylpyrazole insecticide with a similar mode of action to cyclodienes. To investigate the possible occurrence of these mutations in the Cat Flea, Ctenocephalides felis (Bouch´ e), a 176-bp fragment of the Cat Flea Rdl gene, encompassing the mutation site, was PCR amplified and sequenced from nine laboratory Flea strains. The A302S mutation was found in eight of the nine strains analysed, although the relative frequency of the mutant allele varied between strains. Only one strain (R6) was found to be homozygous for the S302 allele in all the individuals tested, and this correlated with previous reports of low-level fipronil resistance in this strain. A PCR-based diagnostic assay, capable of screening individual Fleas for this mutation, was developed and used to survey a range of Fleas collected at random from veterinary clinics in the UK and USA. The A302S mutation was present at a high frequency in these domestic pet populations. 2004 Society of Chemical Industry