Comparative in vitro evaluation of contact activity of fluralaner, spinosad, phoxim, propoxur, permethrin and deltamethrin against the northern fowl mite, Ornithonyssus sylviarum.

BackgroundNorthern fowl mites (Ornithonyssus sylviarum) are obligate hematophagous ectoparasites of both feral birds and poultry, particularly chicken layers and breeders. They complete their entire life-cycle on infested birds while feeding on blood. Infestations of O. sylviarum are difficult to control and resistance to some chemical classes of acaricides is a growing concern. The contact susceptibility of O. sylviarum to a new active ingredient, fluralaner, was evaluated, as well as other compounds representative of the main chemical classes commonly used to control poultry mite infestations in Europe and the USA.MethodsSix acaricides (fluralaner, spinosad, phoxim, propoxur, permethrin, deltamethrin) were dissolved and serially diluted in butanol:olive oil (1:1) to obtain test solutions used for impregnation of filter paper packets. A carrier-only control was included. Thirty adult northern fowl mites, freshly collected from untreated host chickens, were inserted into each packet for continuous compound exposure. Mite mortality was assessed after incubation of the test packets for 48 h at 75% relative humidity and a temperature of 22 °C.ResultsAdult mite LC50 /LC99 values were 2.95/8.09 ppm for fluralaner, 1587/3123 ppm for spinosad, 420/750 ppm for phoxim and 86/181 ppm for propoxur. Permethrin and deltamethrin LC values could not be calculated due to lack of mortality observed even at 1000 ppm.ConclusionsNorthern fowl mites were highly sensitive to fluralaner after contact exposure. They were moderately sensitive to phoxim and propoxur, and less sensitive to spinosad. Furthermore, the tested mite population appeared to be resistant to the pyrethroids, permethrin and deltamethrin, despite not being exposed to acaricides for at least 10 years

Poultry red mite (Dermanyssus gallinae) infestation:A broad impact parasitological disease that still remains a significant challenge for the egg-laying industry in Europe

Abstract The poultry red mite, Dermanyssus gallinae, has been described for decades as a threat to the egg production industry, posing serious animal health and welfare concerns, adversely affecting productivity, and impacting public health. Research activities dedicated to controlling this parasite have increased significantly. Their veterinary and human medical impact, more particularly their role as a disease vector, is better understood. Nevertheless, red mite infestation remains a serious concern, particularly in Europe, where the prevalence of red mites is expected to increase, as a result of recent hen husbandry legislation changes, increased acaricide resistance, climate warming, and the lack of a sustainable approach to control infestations. The main objective of the current work was to review the factors contributing to this growing threat and to discuss their recent development in Europe. We conclude that effective and sustainable treatment approach to control poultry red mite infestation is urgently required, included integrated pest management

Safety of fluralaner oral solution, a novel systemic poultry red mite treatment, for chicken breeders’ reproductive performances

Abstract Background Poultry mites are the most significant pest affecting production systems in the chicken egg-laying industry, altering the health condition of the birds, and causing stress, mortality and decline of egg quality impacting economic performance. Fluralaner is a novel systemic parasiticide that is effective against poultry mites (Dermanyssus gallinae, Ornithonyssus sylviarum) in chickens after oral administration. The evaluation of the safety of this new product in breeder chickens is particularly relevant because poultry mite infestation affects long cycle production systems, such as layers and breeders farms, for which the productivity heavily depends on the health of the reproductive function. This study was designed to investigate the safety for reproductive performances of fluralaner in male and female chickens at 3 times the recommended dose (1.5 instead of 0.5 mg/kg body weight) and 2 times the recommended duration (4 administrations instead of 2 administrations, with a 7 day interval between administrations). Methods This randomized, parallel-group, blinded study included 432 Bovans brown parent stock chickens (48 males and 384 females, 17-week old). Birds were randomly assigned to 16 pens (three males and 24 females per pen), and then each pen assigned to one of the two treatment groups (8 pens, i.e. 216 birds per group). Fluralaner was administered via drinking water on a total of four occasions 7 days apart, at daily doses of 1.5 mg fluralaner/kg body weight, equivalent to 3 times the recommended dose of fluralaner per administration and 2 times the recommended number of administrations. Birds supplied with non-medicated drinking water served as controls. The treatments were given at time of peak egg production in the bird’s life: i.e. at 30 to 34 week of age. During that period, all adult chickens were clinically observed. The reproductive performances were carefully monitored including the number of eggs laid, egg weight, fertility and hatchability. Furthermore, the health and viability (up to 14 days of life) of randomly selected chicks was also monitored. Results There were no clinical findings related to fluralaner treatment. There were no statistically significant differences between the reproductive performances of treated and control groups, nor in their progeny chickens viability. Conclusions Oral administration of fluralaner was well tolerated by breeder chickens with a safety margin of approximately 3-fold obtained. Fluralaner had no effect on the egg number, weight and fertility, and no effect on egg hatchability or chick viability. Based on these results, a safe use of the new mite treatment proposed with fluralaner administered via drinking water is expected in layer and breeder field industrial conditions

Field efficacy and safety of fluralaner solution for administration in drinking water for the treatment of poultry red mite (Dermanyssus gallinae) infestations in commercial flocks in Europe

Abstract Background Welfare concerns, production losses caused by Dermanyssus gallinae, the poultry red mite (PRM), and widespread mite resistance to environmentally applied acaricides continue to drive an urgent need for new and effective control measures. Fluralaner is a novel systemic acaricide developed to address that need. A series of field studies was initiated to investigate the safety and efficacy of a fluralaner solution (10 mg/ml) administered in drinking water at a dose rate of 0.5 mg/kg on two occasions with a 7-day interval, for treatment of natural PRM infestations in chickens. Methods Blinded, negative-controlled studies were completed in Europe across eight layer, two breeder, and two replacement chicken farms. At each farm, two similar flocks were housed in similar PRM-infested units (either rooms within a building, or separate buildings) varying from 550 to 100,000 birds per unit. One unit at each farm was allocated to fluralaner treatment, administered in drinking water on Days 0 and 7. One unit remained untreated. Mite traps were placed throughout each unit on Days -1, 0 or 1, 3, 6, 9, and 13 or 14, then at weekly or two-weekly intervals, retrieved after 24 h and processed for mite counts. Efficacy at each farm was assessed by mean PRM count reductions from traps in treated units compared with those from control units. Production parameters and safety were also monitored. Results Efficacy was 95.3 to 99.8% on Day 3 and 97.8 to 100% on Day 9, thereafter remaining above 90% for 56 to 238 days after treatment initiation. Post-treatment improvement in egg-laying rate was greater by 0.9 to 12.6% in the treated group at 9 of the 10 layer or breeder farms. There were no treatment-related adverse events. Conclusion Fluralaner administered at 0.5 mg/kg via drinking water twice, 7 days apart, was well tolerated and highly efficacious against the PRM in naturally infested chickens representing a range of production types and management systems. The results indicate that this novel treatment has potential to be the cornerstone of an integrated approach to reducing or eliminating the welfare and productivity costs of this increasingly threatening pest

Efficacy and safety assessment of a water-soluble formulation of fluralaner for treatment of natural Ornithonyssus sylviarum infestations in laying hens

Abstract Background Northern fowl mite, Ornithonyssus sylviarum (Canestrini & Fanzago, 1877), infestations can stress birds, impairing welfare and causing substantial economic losses. A study was undertaken to determine the efficacy of an ectoparasiticide solution (fluralaner) for oral administration in the treatment of mite-infested hens. Methods Clinically healthy, naturally mite-infested laying hens (n = 132), approximately 32 weeks of age, were ranked by Day -9 mite vent counts and randomized among 12 study pens, each to hold one of four treatment groups. Three groups received fluralaner-medicated water by oral gavage at dose rates of 0.25, 0.5 or 1.0 mg/kg on Days 0 and 7; one group was an untreated control (three pens for each group). Five naturally infested untreated birds were included in each pen to act as mite-infested source birds. Thus each pen, treated and control, had six non-source birds for assessment of efficacy, plus five source birds to provide ongoing challenge. Primary efficacy assessments were based on mean O. sylviarum vent counts from non-source birds in the control and treated group pens on Days 1, 2, 6, 8, 12, 15, 19, 22 and 26. Results Source-birds maintained infestations throughout the study, validating the challenge to study birds. On Days 1 through 22, mean control group mite counts were significantly greater than those of the treated groups (P ≤ 0.013). Relative to the control group, mean O. sylviarum counts were reduced by at least 90% from Day 6 through Days 19, 22 and 22 in the fluralaner 0.25, 0.5 and 1.0 mg/kg groups, respectively. On Day 19, mean mite counts were lower in the 0.5 and 1.0 mg/kg groups compared with the 0.25 mg/kg group (P ≤ 0.018), and in the 1.0 mg/kg compared with the 0.5 mg/kg group (P = 0.014). There were no adverse events in treated birds. Conclusions A fluralaner solution administered twice by gavage to laying hens with a one-week between-treatment interval was safe and effective in quickly controlling O. sylviarum infestations despite continuous challenge from infested birds. By eliminating mites, this fluralaner solution has the potential to improve bird health and productivity, and to eliminate the burden of topical pesticide application

Safety of fluralaner oral solution, a novel systemic antiparasitic treatment for chickens, in laying hens after oral administration via drinking water

Abstract Background Poultry mites are the most significant pest affecting production systems in the egg-laying industry. Fluralaner is a novel systemic insecticide and acaricide that is effective against poultry mites (Dermanyssus gallinae, Ornithonyssus sylviarum) in chickens after oral administration. This study investigated the safety of oral administration of a 1% solution of fluralaner in drinking water to laying hens at the recommended treatment dose and at multiples of this dose. Methods One hundred-twenty healthy 28-week-old laying hens, weighing 1.4–2.1 kg at first administration, were included in the study, and allocated to 4 treatment groups of 30 hens each receiving daily doses of 0, 0.5, 1.5 and 2.5 mg fluralaner/kg body weight, equivalent to 0, 1, 3, and 5 times the recommended dose of fluralaner. The product was administered via drinking water on a total of six occasions, as 3-day treatment periods twice with an interval of 4 days with no treatment (treatment on days 1, 2, 3 and 8, 9, 10), representing 3 times the recommended number of administrations. Hens supplied with non-medicated drinking water served as controls. During the study, all hens were clinically observed, and their health was carefully monitored including body weight, food and water consumption, hematology, clinical chemistry, and withdrawal reflex test. Eggs laid over the study were evaluated for main characteristics (e.g. weight, shape, strength, shell thickness and soundness, albumen height, yolk color, Haugh unit and presence of blood and/or meat spots). Following euthanasia of the hens at the end of the second treatment period (day 11) or 18 days later (day 29), complete gross post-mortem examination, including organ weight determination, and histopathological examination of multiple tissues were conducted. Results There were no clinical findings related to fluralaner treatment. Statistically significant differences between the treated groups and the control group were observed for some clinical pathology parameters; none of these findings were considered to be of clinical nor zootechnical relevance. Organ weights, gross post mortem and histopathological examinations did not reveal any finding associated with treatment with fluralaner. Conclusions Oral administration of fluralaner via drinking water at the recommended treatment dose (0.5 mg/kg body weight twice at 1-week interval), is well tolerated and has a high safety margin up to an overall dose of 15 times the recommended one (5 times the daily dose given 3 times the number of days) in healthy adult laying hens. Based on the present results, the use of the new mite treatment based on fluralaner administered via drinking water is expected to be safe for laying hens under industrial conditions, and to have no negative impact on their egg quality and production

Comparative in vitro evaluation of contact activity of fluralaner, spinosad, phoxim, propoxur, permethrin and deltamethrin against the northern fowl mite, Ornithonyssus sylviarum.

BackgroundNorthern fowl mites (Ornithonyssus sylviarum) are obligate hematophagous ectoparasites of both feral birds and poultry, particularly chicken layers and breeders. They complete their entire life-cycle on infested birds while feeding on blood. Infestations of O. sylviarum are difficult to control and resistance to some chemical classes of acaricides is a growing concern. The contact susceptibility of O. sylviarum to a new active ingredient, fluralaner, was evaluated, as well as other compounds representative of the main chemical classes commonly used to control poultry mite infestations in Europe and the USA.MethodsSix acaricides (fluralaner, spinosad, phoxim, propoxur, permethrin, deltamethrin) were dissolved and serially diluted in butanol:olive oil (1:1) to obtain test solutions used for impregnation of filter paper packets. A carrier-only control was included. Thirty adult northern fowl mites, freshly collected from untreated host chickens, were inserted into each packet for continuous compound exposure. Mite mortality was assessed after incubation of the test packets for 48 h at 75% relative humidity and a temperature of 22 °C.ResultsAdult mite LC50 /LC99 values were 2.95/8.09 ppm for fluralaner, 1587/3123 ppm for spinosad, 420/750 ppm for phoxim and 86/181 ppm for propoxur. Permethrin and deltamethrin LC values could not be calculated due to lack of mortality observed even at 1000 ppm.ConclusionsNorthern fowl mites were highly sensitive to fluralaner after contact exposure. They were moderately sensitive to phoxim and propoxur, and less sensitive to spinosad. Furthermore, the tested mite population appeared to be resistant to the pyrethroids, permethrin and deltamethrin, despite not being exposed to acaricides for at least 10 years

In vitro activity of fluralaner and commonly used acaricides against Dermanyssus gallinae isolates from Europe and Brazil

Abstract Background The poultry red mite Dermanyssus gallinae negatively impacts bird welfare and health, and interferes with egg production and quality, while emerging acaricide resistance limits control options. Fluralaner, a novel miticide for administration in drinking water, is approved for control of D. gallinae infestations. Mite sensitivity testing is relevant to gauge field isolate susceptibility to available treatments. Methods Thirteen D. gallinae isolates collected during 2014 through 2016 from farms in Germany, France, Spain and Brazil, and a 2001 laboratory-maintained isolate were used for acaricide contact sensitivity testing. Tested compounds were cypermethrin, deltamethrin, phoxim, propoxur, and the recently available acaricides, spinosad and fluralaner. In each study, at least one isolate was exposed to increasing concentrations of at least one acaricide. In one study, additional testing determined the sensitivity of the 2001 isolate to fluralaner using a mite-feeding test, and of fluralaner, phoxim and spinosad using an immersion test. At least two replicates were used for each dilution. Vehicle and untreated controls were also included. Results Based on 90% mortality (LC90) values, the laboratory isolate was susceptible to fluralaner (15.6–62.5 parts per million, ppm), phoxim ( 4000 ppm). An isolate from Spain demonstrated reduced sensitivity to phoxim, propoxur and deltamethrin; an isolate from Brazil showed reduced sensitivity to propoxur and cypermethrin. Mite LC90 when exposed to fluralaner by blood feeding was < 0.1 ppm. Conclusions Contact sensitivity testing indicated apparent resistance to at least one of phoxim, deltamethrin, cypermethrin and propoxur in 13 field isolates from Europe and Brazil. All isolates were highly susceptible to fluralaner. Fluralaner was approximately 1000 times more active by feeding than by contact. Fluralaner’s distinct mode of action and efficacy against isolates largely refractory to those acaricides, makes it a promising option for the control of D. gallinae infestations of poultry

Nanoencapsulated deltamethrin as synergistic agent potentiates insecticide effect of indoxacarb through an unusual neuronal calcium-dependent mechanism

International audienceThe use of neurotoxic chemical insecticides has led to consequences against the environment, insect resistances and side-effects on non-target organisms. In this context, we developed a novel strategy to optimize insecticide efficacy while reducing doses. It is based on nanoencapsulation of a pyrethroid insecticide, deltamethrin, used as synergistic agent, combined with a non-encapsulated oxadiazine (indoxacarb). In this case, the synergistic agent is used to increase insecticide efficacy by activation of calcium-dependant intracellular signaling pathways involved in the regulation of the membrane target of insecticides. In contrast to permethrin (pyrethroid type I), we report that deltamethrin (pyrethroid type II) produces an increase in intracellular calcium concentration in insect neurons through the reverse Na/Ca exchanger. The resulting intracellular calcium rise rendered voltage gated sodium channels more sensitive to lower concentration of the indoxacarb metabolite DCJW. Based on these findings, in vivo studies were performed on the cockroach Periplaneta americana and mortality rates were measured at 24 h, 48 h and 72 h after treatments. Comparative studies of the toxicity between indoxacarb alone and indoxacarb combined with deltamethrin or nanoencapsulated deltamethrin (LNC-deltamethrin), indicated that LNC-deltamethrin potentiated the effect of indoxacarb. We also demonstrated that nanoencapsulation protected deltamethrin from esterase-induced enzymatic degradation and led to optimize indoxacarb efficacy while reducing doses. Moreover, our results clearly showed the benefit of using LNC-deltamethrin rather than piperonyl butoxide and deltamethrin in combination commonly used in formulation. This innovative strategy offers promise for increasing insecticide efficacy while reducing both doses and side effects on non-target organisms