Adult flea Development

Flea Development

Efficacy of indoxacarb applied to cats against the adult cat flea, Ctenocephalides felis, cat flea, cat flea eggs and adult cat flea Development.

The cat flea, Ctenocephalides felis, is the most important ectoparasite of cats and dogs in most regions of the world. Once cat cat cat fleas get a bunch, they mate and begin laying cat flea eggs within 24 – 48 hours. Fleas deposit their cat flea eggs to the haircoat of their cat or dog with the cat flea eggs falling off in the premises where within a few weeks they grow into adult cat fleas. Since female cat fleas can create 40 – 50 cat flea eggs/day it doesn’t take long for enormous numbers of cat flea eggs and finally emerging cat fleas to collect within the assumptions.

Presently, most cat flea control relies on residual topical anaesthetic remedies or oral drugs. The principal focus of the thematic and systemic cat flea control efforts is to induce cat fleas into”extinction” in a localised environment (home or yard) by preventing reproduction.

Eradication of a Flea Infestation

Elimination of an existing cat flea infestation is accomplished either by killing recently acquired cat fleas using a residual adulticide until they could commence reproduction and affecting the viability of the cat flea eggs they produce through the use of insect growth regulators or other ovicidal chemicals.
For a topical or systemic insecticide to stop cat flea egg production, the extra action has to be enough to kill or leave moribund recently acquired cat fleas within 24 hours.

Quite a few in-home and multicentric research on three continents has shown that this approach to cat flea control can be practical. Indoxacarb is a publication oxadiazine insecticide that controls a broad spectrum of insects and has been initially developed for use on many different plants including vegetables, fruit trees, cotton and row crops. Indoxacarb is a pro-insecticide that’s metabolised within the insect into a more active form: An N-decarbomethoxylated metabolite of indoxacarb.

Cat Fleas


This metabolic conversion of indoxacarb, called bioactivation, is attributed to actions of esterase and amidase enzymes inside the insect. The active metabolite of indoxacarb exerts its effect by blocking the voltage-gated sodium ion channels in insects and is at least forty times more potent than parent indoxacarb in its ability to prevent sodium channel ion present. Mammals exhibit minimal bioactivation of indoxacarb and sodium channel binding studies in rats demonstrate that the active indoxacarb metabolite has considerably weaker potency against mammalian sodium channels compared to insect channels.

This analysis was undertaken to assess the efficacy of a newly developed spot-on formulation of indoxacarb applied to cats from adult cat fleas, flea egg production and growth of cat fleas from cat flea eggs to adults.

Nineteen (10m:9f; > 6mo; 2.7 to 4.2 kg), purpose-bred domestic shorthair cats were used in this study. Cats used in this investigation had no exposure to ectoparasiticides before therapy and were in good health during the study. Cats were housed individually in standard stainless steel with solid sides and rear, with a steel-barred door.

Cats were divided by the strong stainless-steel cage walls. Cats were fed a commercial dry cat-food ration. Water was available ad libitum. A licensed veterinarian conducted physical tests before the first cat flea infestation, and cats were determined to be in good health and free of any preexisting dermal lesions. All animal care procedures conformed to guidelines established by the Institutional Animal Care and Use Committee at Kansas State University (Approval No. 3124).

On Day -8, all cats were infested with 50 adult cat fleas, C. felis, (KS1 breed ) 1 to 5 days post-emergence. On Day -5, cat flea repellent counts were conducted to assess the susceptibility of each cat to keep experimental infestations and for arbitrary allocation of the cats into the treatment groups. Cats were combed using a fine-toothed cat flea comb with 12 to 13 teeth/cm. Flea removal has been accomplished by cleaning each cat entirely for 10 minutes. If five or more cat fleas were recovered in this period, the cat was combed for an extra five minutes.

If any cat fleas were recovered during the next combing period, the cats were combed for an extra five minutes. Personnel conducting cat flea combing and cat flea counts were blinded to treatment groups. The 16 cats (7m:9f) with the maximum pre-treatment cat flea counts were used for the analysis. In sex, cats have been ranked from highest to lowest cat flea count, together with the female cat with cheapest cat flea amount placed in male sex grouping, and obstructed in 2 groups comprising eight cats each.

Cats (4m:4f) in treatment group 1 were treated topically with indoxacarb (two – 4.0 kg were treated with 0.51 mL, and cats 4.1 kg were treated with 1.03 mL indoxacarb, 19.5percent w/v; ACTIVYL[R] Merck Animal Health) applied using the commercial product pipette or a syringe. Treatment was administered by parting the hair with the tip of the pipette or needle at the bottom of the skull of the cat, and the whole contents were applied directly to your skin. Cats (3m:5f) in treatment group 2 served as untreated controls. Cats were detected following treatment for any adverse events related to the remedies.

Efficacy evaluations

On Days -2, 7, 14, 21, 28, 35, and 42, each cat was infested with roughly 50 unfed cat fleas, C. felis (KS1 breed ). On Days 1, 2, and 3, and at 2 and three times after every post-treatment reinfestation cat flea eggs were collected from the pan under each cat cage. Before the cat flea egg collections, cats were massaged/brushed vigorously by hand for ~20 seconds in their cages to dislodge any cat flea eggs in the cat’s hair coat, allowing the cat flea eggs to fall in the drip pan beneath the cage.

Eggs collected were counted by putting the cat flea eggs in a glass Petri dish and counted under a dissecting microscope. At approximately 72 hours following infestation or treatment, each cat has been combed to remove and count live cat fleas. The viability of cat flea eggs was determined by placing up to 100 cat flea eggs to glass Petri dishes containing cat flea growth media and carrying in a rearing chamber (I-30B, Percival Manufacturing Co., Boone, IA) at 27-28[degrees]C, 70-80% relative humidity, 24 hours dark.

If less than 100 cat flea eggs were collected, the whole sample was put into the Petri dish containing cat flea growth media and likewise processed. At 10 – 12 days after cat flea egg collection, pupae (and any larvae that hadn’t finished cocoon formation) were sifted from the press and put into plastic vials with lids. Adult development was determined by counting adult cat fleas at 28 days after cat flea egg collection. Personnel conducting comb counts, cat flea egg sets and viability assessments were blinded to treatment group allocation.

Data at each time point were analysed separately. The adult cat flea and cat flea egg count data were transformed before analysis using the Y = log (x + 1) transformation. The log-transformed data were analysed by a mixed linear model including treatment as the fixed effect, and block as the random effect. Least squares mean they were used for treatment comparisons and were back-transformed to obtain the estimates of geometric mean cat flea egg and cat flea counts.

Percentages of the emerging adult cat flea count were analysed by a mixed linear model including treatment as the fixed effect, and block as the random effect. A two-tailed evaluation was used for the comparison between groups. Statistical significance was declared when p < 0.05. The principal application was SAS version 9.3.

Per cent control of adult cat fleas was calculated using geometric means with Abbott’s formula: [formula omitted]

* MC is the geometric mean number of total adult live cat fleas on untreated cats
* MT is the geometric mean number of entire adult live cat fleas on treated cats.

The percentage control of cat flea egg production and cat flea egg yolk were also calculated using Abbott’s formula by adjusting the average number of cat flea eggs produced and mean percentage of new cat fleas from treated. Cats using the average number of cat flea eggs produced and mean rate of new cat fleas generated by cat fleas on untreated control cats.

All cats contained in the analysis revealed adequate pretreatment cat flea retention with day -5 cat flea points ranging from 16 – 38 cat fleas/cat. Nontreated cats also maintained sufficient cat flea infestations throughout the analysis with geometric mean cat flea counts ranging from 19.3 to 28.0.
Geometric mean adult cat flea counts and percentage effectiveness relative to non-treated controls for cats treated with a 19.5percent w/v indoxacarb topical spot-on

Cats at the indoxacarb treatment group were administered an average of 33.7 mg/kg (27.3 – 47.8 mg/kg) indoxacarb. This single dose of indoxacarb produced highly significant reductions in geometric mean cat flea counts on dogs that are treated throughout the whole 45 days of the study (P < 0.001, Table 1). Treatment with indoxacarb supplied 100% efficacy after apprehended daily -2, 7, 14, 21 and 28 and 99.6% decrease in geometric mean cat flea counts after infestations on days 35 and 42 (Table 1).

Geometric mean cat fleas, cat flea egg counts for the indoxacarb-treated cats were significantly lower than those for nontreated controls at all post-treatment evaluations (P < 0.001, Table 2). Egg production from indoxacarb treated cats was decreased by 66.2% over 24 hours after treatment and 99.9% within 72 hours of therapy. For subsequent infestations, cat flea egg production was non-existent from treated cats outside to day 30 and 99.9percent daily 31 relative to nontreated cats (Table 2).

Egg production was still markedly decreased by 95.8% and 98.7percent on days 44 and 45, respectively. The geometric mean number of cat flea eggs produced from cat fleas on control cats from day nine daily 45 post-treatment ranged from 229.7 – 1,086.1. The geometric mean number of cat flea eggs out of indoxacarb treated cats was highest on day 44 in 9.7 cat flea eggs/cat (Table 2).

Table 2:
Geometric mean cat flea, cat flea egg counts and percentage effectiveness relative to non-treated controls for cats treated with a 19.5percent w/v indoxacarb topical spot-on. Based on percentage adult development, indoxacarb treatment had an apparent lethal impact on the viability of cat flea, cat flea eggs collected from treated cats on days 1-3 and days 31 and 38 (P < 0.001, Table 3). Since no cat flea eggs were collected from indoxacarb treated cats from days, 9 – 30 no percentage adult cat flea development analysis could be conducted. An immediate impact on cat flea egg viability based on percentage adult emergence wasn’t discovered on post-treatment days 44 and 45.

But when cat flea egg viability is considered in addition to the marked decrease in cat flea egg numbers, indoxacarb did demonstrate a marked impact upon the reproductive success of these cat fleas even at post-treatment day 45 (Table 3). The combination of the geometric mean number of cat flea eggs produced and the percentage of adult emergence from these cat flea eggs leads to the predicted adult development or reproductive success.

The predicted adult development from cat flea eggs produced by cat fleas on the untreated control cats ranged from 177.5 – 908.2 emerging cat fleas/cat whereas the decrease in anticipated cat flea development from indoxacarb treated cats was 100 per cent from days two – 31 and was still 96.8% and 99.0percent on times 44 and 45, respectively.

Geometric mean percentage adult development predicted adult development and per cent effectiveness relative to non-treated controls for called adult cat flea development from cat flea eggs collected from cats treated with a 19.5percent w/v indoxacarb topical spot-on.

There were no adverse events related to indoxacarb remedies in this study.
Veterinarians and pet owners must anticipate when properly applied indoxacarb spot-on will restrain the present cat flea burden on a cat and that there should be a quick decrease in cat flea egg production from the current cat flea infestation. Within two days of the program, cat flea egg production was almost entirely halted (98.9% decrease ). Since not one of these cat flea eggs produced adult cat fleas, no dissemination of viable cat flea eggs happened from treated cats within two days of therapy.

Most currently available residual topical spot-on and systemic insecticide formulations are promoted to supply a minimum of 30 days of cat flea control. Indoxacarb spot-on indeed provided and exceeded that amount of power. A single use of the indoxacarb provided [greater than or equal to]99.6% management of adult cat fleas on cats for at least 45 days following therapy.

Following treatment, cat flea egg production from weekly cat flea reinfestation was decreased by [greater than or equal to]99.9percent five or more weeks. Consumption of blood is essential before cat fleas may commence reproduction and cat flea egg production doesn’t start until 24-48 hours after females take their first blood meal.

Consequently, if a residual insecticide can kill or create toxicity in recently acquired cat fleas within 24 hours, cat flea egg production should be reduced or stopped. Although this study didn’t evaluate the residual speed of kill of indoxacarb or decrease in blood intake by adult cat fleas, it did demonstrate that indoxacarb had a profound impact upon cat flea egg production. This indicates that indoxacarb is quickly toxic to cat fleas and thus markedly reduces blood feeding by cat fleas.

Indoxacarb also had an impact on adult cat flea development from cat flea eggs. Although this study didn’t evaluate cat flea egg hatch directly, it’s anticipated that the effect of indoxacarb was on cat flea egg yolk. Eggs collected from trays under treated cats were removed and sorted from all debris out of those cats.

The cat flea eggs were then placed into regular rearing media. After this process, any larvae hatching from these cat flea eggs could have had no further contact with indoxacarb. Similar marked deadly effect on cat flea egg viability with a cat flea adulticide was previously observed with selamectin.

Effective residual cat flea adulticides should have an adequate residual activity to provide for the continuing kill of most if not all of the newly emerging cat fleas that jump onto the pet between applications. If a cat flea product also has an impact upon the viability of the cat flea eggs produced by any female cat flea residing the adulticidal effect, that product would markedly suppress the reproductive success of a cat flea population.

In this study, indoxacarb demonstrated marked cat flea kill, a profound decrease in cat flea egg production and apparent ovicidal action, as was observed in other insect species. This combination of features provided [greater than or equal to]99.9% decrease in reproductive success (predicted development ) for five weeks after a single application of indoxacarb. Good use of indoxacarb to cats at a cat flea infested house should efficiently induce the cat flea population to extinction.

This study was conducted with the KS1 cat flea breed. Several previous studies have shown that this strain has decreased susceptibility or outright resistance to carbaryl, chlorpyriphos, fenthion, fipronil, imidacloprid, permethrin, pyrethrins, and spinosad. This study revealed that indoxacarb performed well against this KS-1 cat flea breed.

A topical anaesthetic formula of indoxacarb supplied 100% effectiveness against cat flea infestations on cats for four months after a single treatment and was providing a 99.6% decrease in cat flea counts through week 6. Indoxacarb eliminated or reduced cat flea egg production for the whole evaluation period. The formula also reduced the viability of the few cat flea eggs which were produced through Day 38. Given indoxacarb’s impact on adult cat fleas, cat flea egg production and cat flea egg yolk; it seems this formulation can disrupt cat flea breeding for at least six months following therapy.

Data collection and entry and revision of manuscript; KH assisted in the design of the study, observation of research and manuscript revision. FS conducted the statistical analysis of this data. All authors reviewed and approved the last manuscript.