Initial evaluations of the effectiveness of spinetoram as a long-acting, oral systemic pulicide for controlling cat flea (Ctenocephalides felis) infestations on dogs

Recent Advancements in the Control of Cat Fleas

Simple Summary

The cat flea Ctenocephalides felis felis is the most important pest of domesticated cats and dogs worldwide. This review covers the recent advancements in the control of cat fleas. Over the years, there has been an interest in using ecologically friendly approaches to control fleas. To date, no biological, natural, or cultural means have been discovered that mitigate flea infestations. The recent registration of novel topical and oral therapies promises a new revolution in the control of fleas and ticks and the diseases associated with them.

Abstract

With the advent of imidacloprid and fipronil spot-on treatments and the oral ingestion of lufenuron, the strategies and methods to control cat fleas dramatically changed during the last 25 years. New innovations and new chemistries have highlighted this progress. Control strategies are no longer based on the tripartite approach of treating the pet, the indoor environment, and outdoors. The ability of modern therapies to break the cat flea life cycle and prevent reproduction has allowed for the stand-alone treatments that are applied or given to the pet. In doing so, we have not only controlled the cat flea, but we have prevented or reduced the impact of many of the diseases associated with ectoparasites and endoparasites of cats and dogs. This review provides an update of newer and non-conventional approaches to control cat fleas.

Deciphering the Metabolic Pathway Difference Between Saccharopolyspora pogona and Saccharopolyspora spinosa by Comparative Proteomics and Metabonomics

Butenyl-spinosyn, a secondary metabolite produced by Saccharopolyspora pogona, exhibits strong insecticidal activity than spinosyn. However, the low synthesis capacity and unknown metabolic characteristics of butenyl-spinosyn in wild-type S. pogona limit its broad application and metabolic engineering. Here, we showed that S. pogona exhibited increased glucose consumption ability and growth rate compared with S. spinosa, but the production of butenyl-spinosyn was much lower than that of spinosyn. To further elucidate the metabolic mechanism of these different phenotypes, we performed a comparative proteomic and metabolomic study on S. pogona and S. spinosa to identify the change in the abundance levels of proteins and metabolites. We found that the abundance of most proteins and metabolites associated with glucose transport, fatty acid metabolism, tricarboxylic acid cycle, amino acid metabolism, energy metabolism, purine and pyrimidine metabolism, and target product biosynthesis in S. pogona was higher than that in S. spinosa. However, the overall abundance of proteins involved in butenyl-spinosyn biosynthesis was much lower than that of the high-abundance protein chaperonin GroEL, such as the enzymes related to rhamnose synthesis. We speculated that these protein and metabolite abundance changes may be directly responsible for the above phenotypic changes in S. pogona and S. spinosa, especially affecting butenyl-spinosyn biosynthesis. Further studies revealed that the over-expression of the rhamnose synthetic genes and methionine adenosyltransferase gene could effectively improve the production of butenyl-spinosyn by 2.69- and 3.03-fold, respectively, confirming the reliability of this conjecture. This work presents the first comparative proteomics and metabolomics study of S. pogona and S. spinosa, providing new insights into the novel links of phenotypic change and metabolic difference between two strains. The result will be valuable in designing strategies to promote the biosynthesis of butenyl-spinosyn by metabolic engineering.

Evaluation of an 11.2% spinetoram topical spot-on solution for the control of experimental and natural flea (Ctenocephalides felis) infestations on cats in Europe

Spinetoram is the newest member the spinosyn-class of natural products to be commercialized for flea control on cats in the United States under the tradename Cheristin^® for cats. This report describes results from two laboratory studies and a multi-center clinical field trial designed to confirm the efficacy of a topical spot-on solution containing spinetoram (11.2% w/w, 130 mg/mL) against European strains of the cat flea, Ctenocephalides felis. In the laboratory studies, cats were allocated to one of two treatment groups of eight animals each: negative control (mineral oil) or spinetoram, both applied as a topical spot-on at the base of the skull on Day 0. Cats were infested with ∼100 newly emerged, unfed adult fleas on Days -2 or -1, 7, 14, 21, 28 and 35. To calculate efficacy, fleas were counted and removed 48 h after treatment, and 48 h after each subsequent infestation through week 5. Spinetoram treatments provided 100% efficacy through at least day 16 and ≥ 97% efficacy (arithmetic mean) for one month. For the field trial, 23 clinics from Northern and Southern Europe participated in the study that compared the effectiveness and safety of spinetoram and fipronil/(S)-methoprene treatments over a period of two months. There were 258 and 248 evaluable efficacy cases for month 1 and month 2, respectively, with 300 total evaluable cases for safety. Treatments were administered on Day 0 and again on Day 30 (±3 days). The effectiveness of treatments was calculated based on reduction in live flea counts on Days 14, 30, 44 and 60 (±3 days) relative to flea counts obtained on Day 0. Efficacy (geometric mean percent flea reduction) on Days 14, 30, 44 and 60 was 97.0%, 95.0%, 99.3% and 99.1% for spinetoram, respectively, and 86.1%, 80.9%, 92.4% and 92.3% for fipronil/(S)-methoprene, respectively. Spinetoram was deemed non-inferior at all intervals and superior to fipronil/(S)-methoprene at Days 30 and 60. Clinical signs of flea allergy dermatitis (FAD) were markedly improved following spinetoram treatment, as demonstrated through statistically significant reductions in severity of FAD scores for most of the clinical signs when compared to fipronil/(S)-methoprene treatment. There was a lower overall adverse event incidence rate for spinetoram (5.1%) versus fipronil/(S)-methoprene treatment (11.5%).

The Biology and Ecology of Cat Fleas and Advancements in Their Pest Management: A Review

The cat flea Ctenocephalides felis felis (Bouché) is the most important ectoparasite of domestic cats and dogs worldwide. It has been two decades since the last comprehensive review concerning the biology and ecology of C. f. felis and its management. Since then there have been major advances in our understanding of the diseases associated with C. f. felis and their implications for humans and their pets. Two rickettsial diseases, flea-borne spotted fever and murine typhus, have been identified in domestic animal populations and cat fleas. Cat fleas are the primary vector of Bartonella henselae (cat scratch fever) with the spread of the bacteria when flea feces are scratched in to bites or wounds. Flea allergic dermatitis (FAD) common in dogs and cats has been successfully treated and tapeworm infestations prevented with a number of new products being used to control fleas. There has been a continuous development of new products with novel chemistries that have focused on increased convenience and the control of fleas and other arthropod ectoparasites. The possibility of feral animals serving as potential reservoirs for flea infestations has taken on additional importance because of the lack of effective environmental controls in recent years. Physiological insecticide resistance in C. f. felis continues to be of concern, especially because pyrethroid resistance now appears to be more widespread. In spite of their broad use since 1994, there is little evidence that resistance has developed to many of the on-animal or oral treatments such as fipronil, imidacloprid or lufenuron. Reports of the perceived lack of performance of some of the new on-animal therapies have been attributed to compliance issues and their misuse. Consequentially, there is a continuing need for consumer awareness of products registered for cats and dogs and their safety.