Efficacy of Bravecto® Plus spot-on solution for cats (280 mg/ml fluralaner and 14 mg/ml moxidectin) in the prevention of feline Aelurostrongylus abstrusus infection evaluated in a multi-diagnostic approach.

BACKGROUND: Aelurostrongylus abstrusus is one of the most important respiratory nematodes of felines. Infections may lead to respiratory clinical signs with varying severity or even death, emphasizing the need for preventive treatment of cats with outdoor access to circumvent patent infections. METHODS: Therefore, the preventive efficacy of a spot-on formulation of 280 mg/ml fluralaner and 14 mg/ml moxidectin (Bravecto® Plus spot-on solution for cats, MSD) against A. abstrusus was evaluated in a negative controlled, randomized and partially blinded efficacy study with 28 purpose-bred cats in a non-terminal design. In three different treatment regimes, the minimum recommended dose of 40 mg fluralaner and 2.0 mg moxidectin/kg bodyweight (BW) was administered once at 12, 8 or 4 weeks (study group G1, G2 and G3, respectively) prior to experimental infection with 300 third-stage A. abstrusus larvae, while G4 served as placebo-treated control. RESULTS: From 30 to 46 days post infection (dpi; SD 114 to 130), faeces were sampled to monitor first-stage larvae (L1) excretion for efficacy determination. Secondary efficacy criteria, including respiratory parameters, serological antibody levels and computed tomography (CT) findings, were assessed once before enrolment (SD -7 to -1) and before infection (SD 75 to 83). After infection, CT evaluation was performed once at 47-50 dpi (SD 131 to 134), and respiratory parameters and antibody levels were regularly assessed twice or once a week, respectively (1 up to 78 dpi, SD 85 up to 162). All animals in the control group excreted L1 by 33-37 dpi and remained positive throughout the study period from 41 to 46 dpi (SD 125 to 130). In the treatment groups, only one animal each of G1 and G2 excreted L1 at two consecutive days, and four cats of G1, two of G2 and three of G3 were positive on single occasions. While the geometric mean (GM) of the maximum number of excreted L1 per 5 g of faeces was 7380.89 in the control group (G4), GMs were significantly lower in the treatment groups with 1.63 in G1, 1.37 in G2 and 0.79 in G3. Thus, based on GMs, the reduction in excreted L1 exceeded 99.9% in all three treatment groups. Based on CT severity scores, all lungs of the animals of the control group showed severe pulmonary changes post infection, whereas lungs of the cats of the treatment groups were either unaltered (4 animals), mildly (11 animals), or moderately altered (5 animals). Moreover, seroconversion was observed in all cats of the control group, but not in those of the treatment groups. CONCLUSIONS: The combination of diagnostic methods used in this non-terminal study yielded coherent and reliable results. A single administration of Bravecto® Plus spot-on solution for cats was well tolerated and effective in the prevention of aelurostrongylosis for at least 12 weeks.

Clinical safety and efficacy of a single-dose gentamicin, posaconazole and mometasone furoate otic suspension for treatment of canine otitis externa.

BACKGROUND: A single-dose, in-clinic, veterinary professional-administered treatment for canine otitis externa was developed to improve compliance and canine welfare. METHODS: This multicentre, controlled, examiner-masked, randomised field trial was conducted in 316 dogs over 42 days. Dogs were treated once, on day 0, with the investigational product containing gentamicin, posaconazole and mometasone furoate (Mometamax Ultra [MU]) or twice (days 0 and 7) with a control product containing florfenicol, terbinafine and betamethasone acetate (CP). The primary endpoint was a composite otitis index score of 4 or less (of 12) on day 14 and 3 or less (of 12) on day 28. RESULTS: On day 28, treatment success was recorded in 128 of 143 MU-treated dogs (89.5%), significantly non-inferior to 116 of 133 (87.2%) CP-treated dogs (Farrington-Manning test, Z = 4.1351, p < 0.0001). For mixed cultures of Staphylococcus pseudintermedius and Malassezia pachydermatis, there was 100% treatment success in MU-treated dogs (n = 33), significantly non-inferior to 90.2% (37 of 41) in CP-treated dogs (Farrington-Manning test, Z = 3.1954, p = 0.0007). LIMITATIONS: Efficacy in chronic otitis externa cases was not investigated. Cytology was not used to aid in diagnosis or for identification of secondary pathogens. CONCLUSION: This unique combination, single-dose product is safe and effective in dogs with otitis externa. It offers enhanced compliance, canine welfare and quality of life by eliminating the owner burden of treating this painful condition.

Efficacy of a spot-on formulation containing 280 mg/ml fluralaner and 14 mg/ml moxidectin (Bravecto® Plus) in the prevention of cat aelurostrongylosis under field conditions.

Aelurostrongylus abstrusus is the most important respiratory nematode of domestic cats. Effective control options are crucial to protect health and welfare of cats and to reduce the spread of aelurostrongylosis in both enzootic and free regions. The present study evaluated the efficacy of a spot-on formulation containing 280 mg/ml fluralaner and 14 mg/ml moxidectin (Bravecto® Plus, MSD) in the prevention of aelurostrongylosis in cats under field conditions. One hundred and fifty-two cats from Italy, Hungary and Bulgaria, were randomly divided in two groups, one treated with Bravecto® Plus on Study Days (SDs) 0 and 84 (74 cats, IVP Group) and one left untreated (78 cats, control group). Faecal samples were collected from all animals on SDs 42 ± 4, 84, 126 ± 4 and 168 ± 4 and subjected to the Baermann's technique and species-specific PCR for A. abstrusus. Each cat was subjected to a clinical examination on SDs 0, 84 and 168 ± 4 to check health condition and possible adverse events. The results of the faecal analysis were statistically analyzed for treatment group differences in the percentage of cats negative to the Baermann's test and PCR and percentage of reduction of fecal larvae counts as the primary and secondary efficacy criteria, respectively. The percentage of negative cats was higher in the IVP group compared to the control group and the percentage of reduction of fecal larvae counts in the IVP group compared to the control group was 100%. These results show that two administrations of Bravecto Plus® spot-on 12 weeks apart were safe and effective in the prevention of aelurostrongylosis for a period of almost 6 months.

Field efficacy of fluralaner (Bravecto® chewable tablets) for preventing Babesia canis infection transmitted by Dermacentor reticulatus ticks to dogs.

BACKGROUND: The isoxazoline fluralaner is effective for prevention of Babesia canis transmission from infected Dermacentor reticulatus ticks to dogs for 84 days in a controlled environment. This study was designed to evaluate the effectiveness of fluralaner chewable tablets for sustained prevention of B. canis infection of dogs in endemic areas under natural conditions. METHODS: In Europe, privately owned, clinically healthy pet dogs were enrolled and randomized either to receive fluralaner at 25-56 mg/kg (Bravecto® chewable tablets) on days 0 and 84, or to remain untreated during the D. reticulatus season. Blood samples were collected to evaluate B. canis exposure: on days 0 and 21 (exposure before day 0), during the study and at the end of the tick season (dogs suspected of having become infected after day 0). Efficacy was determined by the percentage reduction in B. canis transmission risk based on the difference in B. canis-positive tests in fluralaner-treated dogs compared with untreated dogs. In addition, ticks collected at monthly intervals throughout the study were identified to species level and females tested for B. canis DNA. RESULTS: A total of 152 dogs were enrolled in the study, although nine dogs were excluded because they tested positive for B. canis DNA or antibodies within 21 days after enrollment. During the study period, no fluralaner-treated dog became positive for B. canis, resulting in calculated efficacy of 100%. However, babesiosis infection was diagnosed in five untreated control dogs (Fisher's exact test, left-sided, P = 0.0312). Tick analyses revealed that one sample collected in Hungary was infected with B. canis. CONCLUSION: Oral administration of Bravecto chewable tablets at the recommended dosage to dogs completely prevented B. canis transmission under field conditions in an endemic area for 12 weeks.

Efficacy of oral fluralaner (Bravecto) against Tunga penetrans in dogs: A negative control, randomized field study in an endemic community in Brazil.

The sand flea Tunga penetrans is one of the zoonotic agents of tungiasis, a parasitic skin disease of humans and animals. The dog is one of its main reservoirs. This negatively controlled, randomized, double-masked clinical trial evaluated the therapeutic and residual efficacy of fluralaner for treatment of dogs naturally infested with T. penetrans. Sixty-two dogs from an endemically affected community in Brazil were randomly assigned to either receive oral fluralaner (Bravecto chewable tablets) at a dose of 25 to 56 mg fluralaner/kg body weight, or no treatment (31 dogs per group). Dogs were clinically examined using a severity score for acute canine tungiasis (SCADT), parasitological examinations as defined by the Fortaleza classification, and pictures of lesions on days 0 (inclusion and treatment), 7 ± 2, 14 ± 2, 21 ± 2, 28 ± 2, 60 ± 7, 90 ± 7, 120 ± 7 and 150 ± 7. The percentage of parasite-free dogs after treatment was >90% between days 14 and 90 post-treatment with 100% efficacy on study days 21, 28 and 60. Sand flea counts on fluralaner treated dogs were significantly lower (p<0.025) than control dogs on all counts from day 7 to 120. The number of live sand fleas on treated dogs was reduced by > 90% on day 7, > 95% on days 14 and 90, and 100% from day 21 to 60, and with a significant difference between groups from day 7 to 120. From day 7 to day 120, mean SCADT scores were significantly reduced in treated dogs with a mean of 0.10 compared to 1.54 on day 120 in untreated dogs. Therefore, a single oral fluralaner administration is effective for treating and achieving long lasting (> 12 weeks) prevention for tungiasis in dogs.

Assessment of fluralaner as a treatment in controlling Dermanyssus gallinae infestation on commercial layer farms and the potential for resulting benefits of improved bird welfare and productivity.

BACKGROUND: Poultry red mite (PRM) (Dermanyssus gallinae) infestations are a cause of anaemia, impaired productivity and stress-related behaviours linked to reduced hen welfare. A study investigated the potential health, welfare and productivity benefits following fluralaner treatment to eliminate PRM from infested hens. METHODS: A PRM-infested layer house was selected on a free-range farm (5400 hens) and an aviary farm (42,400 hens). Fluralaner (Exzolt®; 0.5 mg/kg body weight) was administered twice, 7 days apart (Weeks 0 and 1), via drinking water. Mite populations were monitored by traps. Cameras recorded nighttime hen behaviours weekly, pre- and post-treatment. On the free-range farm, daytime behaviours were also recorded weekly. For pre- and post-treatment corticosterone assessments, eggs were randomly collected on both farms, and blood samples were collected from 50 randomly selected aviary farm hens. Production parameters were assessed using farm records. RESULTS: Throughout the post-treatment period, fluralaner efficacy against PRM was > 99% on both farms. On the aviary and free-range farms, treatment was followed by significant nighttime increases in the proportion of resting hens (P < 0.0001; P = 0.0175, respectively). Significant post-treatment versus pre-treatment nighttime reductions were observed in head shaking (aviary, P < 0.0001; free-range P = 0.0233) and preening (P = 0.0032; P = 0.0018) and on the aviary farm in bouts of body shaking (P = 0.0108), vertical wing shaking (P = 0.0002), head scratching (P = 0.0335), and gentle feather pecking (P < 0.0001). On the free-range farm there were significant daytime reductions in head scratching (P < 0.0001), head shaking (P = 0.0492) and preening (P = 0.0012). Relative to standard production parameters, no differences were detected on the aviary farm, but on the free-range farm the laying rate decline with increasing age was less than expected and the increase in egg weight greater than expected. Post-treatment increases in egg and plasma corticosterone were suggestive of stress factors in addition to mite infestation. Red blood cell counts and haematocrit increased following treatment. CONCLUSION: Fluralaner treatment eliminated mite challenge, leading to improved hen welfare and health, based on reductions in stress-related behaviours and restoration of the anaemia-inducing effects of mite blood feeding.

Efficacy of Bravecto® Plus spot-on solution for cats (280 mg/ml fluralaner and 14 mg/ml moxidectin) for the prevention of aelurostrongylosis in experimentally infected cats.

BACKGROUND: The feline lungworm Aelurostrongylus abstrusus affects the lower respiratory tract in cats worldwide. As infections may lead to chronic respiratory changes or even death, preventive treatment in cats with outdoor access is warranted. METHODS: The preventive efficacy of a spot-on solution (Bravecto® Plus spot-on solution for cats, MSD) against cat aelurostrongylosis was evaluated using three different preventive treatment regimes in a negative controlled, randomized and partially blinded laboratory efficacy study with 31 purposed-bred cats. The minimum recommended dose of 2.0 mg moxidectin + 40 mg fluralaner/kg bodyweight was applied once 12 (Group [G]1), 8 (G2) or 4 (G3) weeks before experimental infection with 300 third-stage larvae (L3) of A. abstrusus. Another group served as untreated control (G4). Individual faecal samples were analysed as of day 30 post infection (pi) to monitor larvae excretion. Necropsy was performed at days 47-50 pi. The lungs were examined macroscopically for pathological findings and (pre-)adult worms were counted to assess preventive efficacy. RESULTS: Beginning at day 32-40 pi, all cats of the control group were constantly shedding larvae of A. abstrusus, whereas only one animal of G1 excreted larvae at several consecutive days. In addition, two cats of G1 and G3 and three of G2 were positive on a single occasion. The geometric mean (GM) of the maximum number of excreted larvae was 7574.29 in the control group compared to 1.10 (G1), 1.19 (G2) and 0.53 (G3), resulting in a GM reduction of > 99.9% in all treatment groups. All lungs of the control animals showed severe or very severe alterations at necropsy, while in 94.44% of the treated cats lung pathology was rated as absent or mild. The GM number of (pre-)adult A. abstrusus retrieved from the lungs was 26.57 in the control group, 0.09 in G1 and 0.00 in G2 and G3. Thus, GM worm count reduction was 99.66% in G1 and 100% in G2 and G3. CONCLUSIONS: A single application of Bravecto® Plus spot-on solution at a dose of 2.0 mg moxidectin + 40 mg fluralaner/kg bodyweight reliably prevents cat aelurostrongylosis for at least 12 weeks.

Assessment of laying-bird welfare following acaricidal treatment of a commercial flock naturally infested with the poultry red mite (Dermanyssus gallinae).

The poultry red mite (PRM), Dermanyssus gallinae, a potential vector of pathogens to animals and humans, causes impaired bird welfare. A study investigated changes in behavioural variables, physiological biomarkers, and health parameters following acaricidal treatment of PRM infestation of laying hens on a commercial farm. Mite traps determined the challenge to 12,700 hens before and after drinking water administration of the acaricide, fluralaner (Exzolt®, 0.5 mg/kg; Weeks 0 and 1). Weekly daytime direct observations and night-time video recordings monitored bird behaviours from Weeks -6 through +6. Blood samples were collected from randomly-selected birds (Weeks -6, -1, and +6). Following treatment, mite count reductions (>99%) were statistically significant (P < 0.0001), as were night-time reductions in the percent of hens showing activity, preening, head scratching (all P < 0.0001), and head shaking (P = 0.0007). Significant daytime reductions were observed in preening and head scratching (both P < 0.0001), head shaking (P = 0.0389), severe feather pecking (P = 0.0002), and aggressive behaviour (P = 0.0165). Post-treatment, comb wounds were significantly reduced (P = 0.0127), and comb colour was significantly improved (P < 0.0001). Heterophil/lymphocyte ratio was significantly reduced at Weeks 1 and 6 (P = 0.0009 and P < 0.0001, respectively). At Week 6, blood corticosterone (P = 0.0041) and total oxidant status (P < 0.0001) were significantly reduced, and haemoglobin and mean corpuscular haemoglobin significantly increased (P < 0.0001). Farm production records indicated that those post-treatment improvements were accompanied by significant reductions in weekly mortality rate (P = 0.0169), and significant recovery in mean weekly egg weights (P < 0.0001) and laying rate (P < 0.0001). The improvements in behavioural variables, physiological biomarkers, and health parameters that were observed following the elimination of PRM on a commercial farm indicate that infestations can be a cause of reduced hen welfare.

Efficacy of orally and topically administered fluralaner (Bravecto®) for treatment of client-owned dogs with sarcoptic mange under field conditions.

BACKGROUND: Successful canine sarcoptic mange treatment requires immediate efficacy to eliminate active mites, and sustained activity to prevent re-infestation from in-contact animals and fomites. With extended acaricidal activity, fluralaner has been shown to be effective for treating this disease. To confirm this potential under field conditions, two fluralaner formulations were administered to mite-infested, client-owned dogs. METHODS: Households qualified for inclusion if they had at least one dog positive for Sarcoptes scabiei mites, confirmed by skin scraping, and at least one dog with clinical signs evocative of sarcoptic mange. Households were allocated to groups of dogs to receive a single treatment with either oral (Bravecto® chewable tablets, MSD Animal Health) or topical (Bravecto® Spot-on, MSD Animal Health), fluralaner at a dose of ≥ 25 mg/kg (range 25-56 mg/kg) on Day 0, or two treatments with oral sarolaner (Simparica® tablets, Zoetis) (Days 0 and 28) at ≥ 2 mg/kg (2-4 mg/kg). All dogs in each household were treated with the same product. On the enrolment day and subsequently on Days 28, 56 and 84, deep skin scrapings were taken from at least five different body areas judged to be most likely to have active mite infestation. At each visit, the dog's mange-associated skin lesions were recorded, and pruritus level was assessed. RESULTS: There were 98 participating households and 135 dogs enrolled across Albania, France, Italy and Portugal. On Day 28, more than 90% of dogs in each group were negative for mites. On Days 56 and 84, all study dogs were free of mites and most dermatological signs of sarcoptic mange had resolved. There were no treatment-related adverse events in any group. CONCLUSIONS: A single treatment of client-owned, sarcoptic mange-affected dogs with either fluralaner chewable tablets or fluralaner spot-on formulation proved a safe and effective treatment of infestations with S. scabiei var. canis, maintained through 84 days (12 weeks) after treatment.

A European field assessment of the efficacy of fluralaner (Bravecto®) chewable and spot-on formulations for treatment of dogs with generalized demodicosis.

BACKGROUND: Recent reports indicate that the isoxazoline compounds have the potential to provide safe and effective treatment of canine generalized demodicosis, a condition that has been traditionally difficult to cure. Controlled field studies are needed to confirm this potential. A study was therefore initiated to investigate the efficacy of a single oral or spot-on treatment with fluralaner, an isoxazoline, compared with multiple topical treatments with imidacloprid-moxidectin, in dogs naturally affected by generalized demodicosis. METHODS: Veterinary clinics in 5 European countries enrolled 134 dogs diagnosed with generalized demodicosis. Dogs were randomized to treatment with either fluralaner chewables, fluralaner spot-on, or topical imidacloprid-moxidectin in a 2:2:1 ratio. Both fluralaner formulations were administered once, at the approved dose rate, on Day 0. Imidacloprid-moxidectin was administered per label on Day 0, and every 4 weeks, more frequently if necessary. At each visit (Days 0, 28, 56, 84), dogs were monitored for demodectic mites using deep skin scrapings and observed for health and for severity of skin lesions. Treatment was considered efficacious if more than 90% of the dogs were free of live mites at both Days 56 and 84. RESULTS: Of 124 dogs completing the study, 57 were diagnosed with juvenile-onset demodicosis and 67 with the adult-onset form. A single treatment with oral or spot-on fluralaner was efficacious, each eliminating mites from at least 98.0% of treated dogs on Days 56 and 84. Against juvenile-onset demodicosis, efficacy of the oral and spot-on formulations was 96.0% and 100%, respectively, and against adult-onset demodicosis 100% and 96.7%. Multiple administrations of imidacloprid-moxidectin were not efficacious, eliminating mites from 87.5% of dogs (92.0% with juvenile-onset demodicosis cured; 81.8% with adult-onset demodicosis). All groups showed a marked reduction in skin lesions by Day 28, with continuing clinical improvement at each subsequent visit through Day 84. There were no treatment-related adverse events. CONCLUSIONS: A single administration of fluralaner chewables or fluralaner spot-on is highly effective against with juvenile-onset and adult-onset forms of generalized canine demodicosis. Topically applied imidacloprid-moxidectin at weekly to monthly intervals over the 84-day study did not achieve the proportion of mite-free dogs required to demonstrate efficacy.

Field effectiveness and safety of fluralaner plus moxidectin (Bravecto® Plus) against ticks and fleas: a European randomized, blinded, multicenter field study in naturally-infested client-owned cats.

BACKGROUND: A spot-on formulation containing fluralaner (280 mg/ml) plus moxidectin (14 mg/ml) (Bravecto® Plus) has been developed to provide broad spectrum parasite protection for cats. The effectiveness and safety of this product against ticks and fleas was assessed in a randomized, controlled, 12-week study in client-owned cats in Germany and Spain. METHODS: Eligible households containing at least one cat with at least two fleas and/or two ticks were allocated randomly in a 2:1 ratio to a single treatment with fluralaner plus moxidectin on Day 0, or three 4-weekly treatments with fipronil (Frontline®). Veterinary staff, masked to treatment, completed tick and flea counts on each cat at 14 ± 2 (2 weeks), 28 ± 2 (4 weeks), 56 ± 2 (8 weeks) and 84 ± 2 days (12 weeks) after the initial treatment. RESULTS: In total, 707 cats (257 with ticks) from 332 households (236 with fleas) were included. Ixodes ricinus (78%) and Rhipicephalus sanguineus complex (18%) ticks were the most commonly identified. Tick and flea counts were lower in the fluralaner plus moxidectin group than in the fipronil group throughout the study and the efficacy of fluralaner plus moxidectin exceeded 97 and 98%, respectively. At 12 weeks, 94.1 and 93.3% of cats from the fluralaner plus moxidectin and 92.2 and 60.3% of cats from the fipronil group were free of ticks and fleas, respectively. Fluralaner plus moxidectin was non-inferior to fipronil (P < 0.0001) at all assessments and superior to fipronil at 2 and 8 weeks for the proportion of cats free of ticks (P < 0.0001). Fluralaner plus moxidectin was superior to fipronil for the proportion of both households and cats free of fleas (P < 0.0001). Both products were safe and well tolerated. CONCLUSIONS: A single application of fluralaner plus moxidectin spot-on was well tolerated by cats and highly effective for 12 weeks against ticks and fleas. Fluralaner plus moxidectin was non-inferior to fipronil for the proportion of ectoparasite-free and consistently superior to fipronil in controlling fleas.

A randomized, blinded, controlled, multi-centered field study assessing the treatment of gastrointestinal nematode infections in cats with fluralaner plus moxidectin spot-on solution (Bravecto® Plus).

BACKGROUND: A spot-on formulation containing fluralaner (280 mg/ml) plus moxidectin (14 mg/ml) (Bravecto® Plus) was developed for the treatment of nematode infections as well as providing 12 weeks of protection against insect and acarine parasites in cats. The effectiveness and safety of this product against feline gastrointestinal nematodes was assessed in naturally-infested, client-owned cats under field conditions in Albania, Bulgaria, Germany and Hungary. METHODS: To be eligible for enrollment in this investigator-blinded study cats had to be at least 10 weeks-old, weigh at least 1.2 kg, be clinically healthy, and have a faecal sample testing positive for nematodes no more than eight days prior to treatment. Cats were stratified into blocks of three in order of presentation at each center and randomly allocated in a 2:1 ratio to be treated topically on Day 0 with fluralaner plus moxidectin (minimum dose rates 40 mg/kg and 2 mg/kg, respectively) or emodepside plus praziquantel (minimum dose rates 3 mg/kg and 12 mg/kg, respectively) (Profender®). Faecal samples were collected from cats prior to treatment and 14 ± 4 days later. RESULTS: There were 182 cats randomized to the fluralaner plus moxidectin group, and 91 to the emodepside plus praziquantel group. Prior to treatment the most commonly identified nematode egg was Toxocara cati, found in 79.1 and 82.4% of cats in the fluralaner plus moxidectin and emodepside plus praziquantel groups, respectively. Eggs of Toxascaris leonina were found in 8.2 and 6.6% of cats; of hookworms in 30.8 and 24.2%; and of Capillaria spp. in 7.1 and 4.3%, respectively. After treatment, faecal samples from 98.3% of fluralaner plus moxidectin treated and 96.6% of emodepside plus praziquantel-treated cats were free of nematode ova. Geometric mean faecal egg count reductions for T. cati, the only eggs found in post-treatment faecal samples, were 99.97% and 99.93%, respectively. Treatment with fluralaner plus moxidectin was non-inferior to emodepside plus praziquantel. Both products were safe and well tolerated by cats treated under field conditions. CONCLUSIONS: This field study confirms that, in addition to 12-week extended duration flea and tick control, fluralaner plus moxidectin provides broad spectrum treatment of nematodes in cats.

The acaricidal speed of kill of orally administered fluralaner against poultry red mites (Dermanyssus gallinae) on laying hens and its impact on mite reproduction.

BACKGROUND: Dermanyssus gallinae, the poultry red mite, is a growing threat to chickens in poultry farms. This nocturnal hematophagous ectoparasite has a rapid rate of proliferation with a negative impact on the birds' health, welfare and productivity resulting in severe economic consequences for poultry farmers. A study was performed with fluralaner, a novel systemic ectoparasiticide, to evaluate its effect on mite vitality and reproduction after oral administration to laying hens. METHODS: Sixteen healthy hens were randomly allocated to two study groups (n = 8). One group was orally treated with fluralaner by gavage at a dose of 0.5 mg/kg bodyweight twice 7 days apart. The negative control group received no treatment. Hens in each group were repeatedly infested with approximately 200 unfed adult D. gallinae at 1, 5, 8, 12, 15, 19, 22 and 26 days after the initial administration. After infestation and feeding for 2.5 h, 25 engorged mites per hen were collected and incubated in tubes. Mites were assessed for vitality (dead/live) at 4, 8, 12, and 24 h after each infestation. Tubes containing eggs and/or living mites were incubated another 8 days for assessment of mite reproductive capacity. RESULTS: Fluralaner demonstrated a fast speed of kill in mites within 4 h post-infestation for 12 days after treatment initiation. An efficacy (mite mortality) of 98.7-100% was achieved. At 15 days after treatment initiation, 100% efficacy was achieved within 24 h post-infestation, and no mite oviposition occurred during this period. Nineteen days after treatment initiation, the mites' ability to generate nymphs was reduced by 90.8%, which decreased to < 24.1% at later infestations. CONCLUSIONS: Fluralaner administered orally to hens twice, 7 days apart, provides efficacy against experimental poultry red mite infestation for at least 2 weeks. The demonstrated rapid speed of kill results in substantial depletion of the mites' oviposition and suggests that fluralaner can be an effective tool in the control of D. gallinae, one of the most urgent problems in poultry farms.

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.

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 of fluralaner (Bravecto™ chewable tablets) for the treatment of naturally acquired Linognathus setosus infestations on dogs.

BACKGROUND: The clinical efficacy of fluralaner chewable tablets (Bravecto™, MSD Animal Health) against naturally acquired Linognathus setosus infestations on dogs was evaluated compared with permethrin (Exspot®, MSD Animal Health) treatment. METHODS: Privately-owned dogs naturally infested with L. setosus from 21 different households were randomly allocated to two treatment groups. Fourteen dogs were treated once orally with fluralaner and ten dogs were treated once topically with permethrin, at the recommended label dose. Live L. setosus on all dogs were counted before treatment and 1, 7, 28 (both groups) and 84 (fluralaner group) days post-treatment according to a coat parting technique at pre-specified locations and lice species were confirmed microscopically. At the same time points, a veterinary dermatology severity score and an owner's perceived pruritus score were recorded. RESULTS: Percentage reduction in geometric mean L. setosus counts, comparing post- with pre-treatment counts within each group, were 85.7% (day 1), 96.8% (day 7) and 100% (days 28 and 84) for the fluralaner (two-sided two-sample t-test, P ≤ 0.0088 for days 1-84) and 67.5% (day 1), 90.3% (day 7) 99.1% (day 28) for the permethrin group (two-sided two-sample t-test, P ≤ 0.0014 for days 7-28). No lice were seen on fluralaner-treated dogs 28 and 84 days post-treatment. In contrast, two permethrin-treated dogs were re-treated at 7 and 28 days after initial treatment because of observed lice. Owner's perceived pruritus scores were reduced compared to pre-treatment levels by 23.8% (day 1), 31.1% (day 7), 70.4% (day 28) and 99.5% (day 84) after fluralaner treatment and 21.3% (day 1), 45.8% (day 7), and 78.1% (day 28) after permethrin treatment. Dermatological signs were improved compared to pre-treatment levels in both treatment groups. CONCLUSIONS: Single oral fluralaner treatment eliminated natural L. setosus infestation on dogs within 28 days and led to complete dermatological recovery that was maintained until the study end on day 84. Single topical permethrin treatment reduced the number of L. setosus by 99.1% at day 28 although two animals required unscheduled re-treatment.

The effect of water and shampooing on the efficacy of fluralaner spot-on solution against Ixodes ricinus and Ctenocephalides felis infestations in dogs.

BACKGROUND: Fluralaner spot-on solution provides immediate and persistent efficacy against tick and flea infestations in dogs and cats for 12-weeks following topical administration. The active ingredient fluralaner is distributed systemically following transdermal absorption. Therefore, this study tested the hypothesis whether water-immersion or shampooing of dogs following administration of fluralaner spot-on solution has an impact on subsequent tick and flea efficacy. METHODS: Thirty-two Beagle dogs were allocated to four study groups of 8 dogs each. On day 0, dogs in the 2 treatment groups received topical administration of fluralaner (Bravecto™ spot-on solution) according to label instructions. Dogs in the 2 corresponding control groups remained untreated. On days 3, 21, 49, and 77 dogs in one treatment group and control group were water-immersed for 2-5 min, while dogs in the other treatment group and control group were shampooed 6-8 min with a commercial foaming micro-emulsion, unscented product. On days 4, 28, 56, and 84 all dogs were co-infested with 50 ± 2 female and 10 ± 2 male Ixodes ricinus and 100 ± 4 Ctenocephalides felis, with tick and flea removal and counts 48 ± 2 h post-infestation. Efficacy against ticks and fleas was calculated for each assessment time point. RESULTS: No treatment-related adverse event was observed in any of the 16 dogs treated with fluralaner spot-on solution during the study. Efficacy against ticks at each assessment time point was between 99.7 and 100 % in the water-immersed group and between 99.2 and 100 % in the shampooed group. Efficacy against fleas was 100 % at each assessment time point as well in the water-immersed as the shampooed group. Tick and flea reduction in both treatment groups was significant at all assessment time points (p < 0.0001). CONCLUSIONS: Neither water-immersion nor shampooing after single topical administration of fluralaner spot-on solution had an impact on the excellent tick and flea efficacy over the 12-week recommended re-treatment interval.

Efficacy of fluralaner spot-on solution against induced infestations with Rhipicephalus sanguineus on dogs.

BACKGROUND: The efficacy of fluralaner spot-on solution administered once topically against induced infestations with Rhipicephalus sanguineus was evaluated in dogs over a 12-week post-treatment period. METHODS: Six negative-controlled studies were conducted, involving a total of 112 adult dogs (57 mixed breed, 47 Beagles, eight Labradors). In each study, dogs were randomized to two groups of eight to ten dogs each. On day 0, dogs in each treated group were topically administered fluralaner spot-on solution once at a dose of 25 mg/kg body weight, while dogs in each control group were not treated. Two days before treatment, and on days 28, 56 and 84 after treatment, all dogs were infested with approximately 50 unfed, adult Rh. sanguineus ticks (sex ratio 1:1). Ticks were removed and counted on days 2, 30 (4 weeks), 58 (8 weeks), and 86 (12 weeks) after treatment to assess efficacy. RESULTS: Efficacy against ticks 2 days after treatment was 91.1 % (study 1), 98.4 % (study 2), 100 % (study 3), 97.6 % (study 4), 99.6 % (study 5), and 99.8 % (study 6). At all other assessment time points, tick efficacy was 95.4-100 %. Tick reduction in all treatment groups was significant at all assessment time points (P < 0.0001). CONCLUSIONS: A single topical administration of fluralaner spot-on solution provides a high level of therapeutic and persistent efficacy against Rh. sanguineus ticks over the subsequent 12 weeks.

A quantitative evaluation of the extent of fluralaner uptake by ticks (Ixodes ricinus, Ixodes scapularis) in fluralaner (Bravecto) treated vs. untreated dogs using the parameters tick weight and coxal index.

BACKGROUND: Fluralaner is a new antiparasitic drug that was recently introduced as Bravecto chewable tablets for the treatment of tick and flea infestations in dogs. Most marketed tick products exert their effect via topical application and contact exposure to the parasite. In contrast, Bravecto delivers its acaricidal activity through systemic exposure. Tick exposure to fluralaner occurs after attachment to orally treated dogs, which induces a tick-killing effect within 12 h. The fast onset of killing lasts over the entire treatment interval (12 weeks) and suggests that only marginal uptake by ticks is required to induce efficacy. Three laboratory studies were conducted to quantify the extent of uptake by comparison of ticks' weight and coxal index obtained from Bravecto-treated and negative-control dogs. METHODS: Three studies were conducted using experimental tick infestation with either Ixodes ricinus or Ixodes scapularis after oral administration of fluralaner to dogs. All studies included a treated (Bravecto chewable tablets, MSD Animal Health) and a negative control group. Each study had a similar design for assessing vitality and weighing of ticks collected from dogs of both groups. Additionally, in one study the coxal index (I. ricinus) was calculated as a ratio of tick's ventral coxal gap and dorsal width of scutum. Tick weight data and coxal indices from Bravecto-treated and negative-control groups were compared via statistical analysis. RESULTS: Ticks collected from Bravecto-treated dogs weighed significantly less (p ≤ 0.0108) than ticks collected from negative-control dogs, and their coxal index was also significantly lower (p < 0.0001). The difference in tick weights was demonstrated irrespective of the tick species investigated (I. ricinus, I. scapularis). At some assessments the mean tick weights of Bravecto-treated dogs were significantly lower than those of unfed pre-infestation (baseline) ticks. The demonstrated tick-killing efficacy was in the range of 94.6 - 100%. CONCLUSIONS: Tick weights and coxal indices confirm that a minimal uptake results in a sufficient exposure of ticks to fluralaner (Bravecto) and consequently in a potent acaricidal effect.

Fluralaner activity against life stages of ticks using Rhipicephalus sanguineus and Ornithodoros moubata IN in vitro contact and feeding assays.

BACKGROUND: Fluralaner is a novel isoxazoline eliciting both acaricidal and insecticidal activity through potent blockage of GABA- and glutamate-gated chloride channels. The aim of the study was to investigate the susceptibility of juvenile stages of common tick species exposed to fluralaner through either contact (Rhipicephalus sanguineus) or contact and feeding routes (Ornithodoros moubata). METHODS: Fluralaner acaricidal activity through both contact and feeding exposure was measured in vitro using two separate testing protocols. Acaricidal contact activity against Rhipicephalus sanguineus life stages was assessed using three minute immersion in fluralaner concentrations between 50 and 0.05 µg/mL (larvae) or between 1000 and 0.2 µg/mL (nymphs and adults). Contact and feeding activity against Ornithodoros moubata nymphs was assessed using fluralaner concentrations between 1000 to 10(-4) µg/mL (contact test) and 0.1 to 10(-10) µg/mL (feeding test). Activity was assessed 48 hours after exposure and all tests included vehicle and untreated negative control groups. RESULTS: Fluralaner lethal concentrations (LC50, LC90/95) were defined as concentrations with either 50%, 90% or 95% killing effect in the tested sample population. After contact exposure of R. sanguineus life stages lethal concentrations were (µg/mL): larvae - LC50 0.7, LC90 2.4; nymphs - LC50 1.4, LC90 2.6; and adults - LC50 278, LC90 1973. After exposure of O. moubata nymphs to fluralaner lethal concentrations were (µg/mL): contact exposure - LC50 720, LC95 1133; and feeding exposure- LC50 0.00007, LC95 0.09. CONCLUSIONS: Fluralaner demonstrates potent in vitro acaricidal activity against all life stages of the brown dog tick, R.sanguineus. The testing of fluralaner contact and feeding routes using O. moubata nymphs demonstrates a high acaricidal activity in both exposure routes.

Onset of activity of fluralaner (BRAVECTO™) against Ctenocephalides felis on dogs.

BACKGROUND: Fluralaner (Bravecto™) is a novel systemic insecticide and acaricide that provides long persistent antiparasitic activity following a single administration at the minimum dose of 25 mg/kg body weight. METHODS: Three negative controlled, randomized studies were conducted in dogs to evaluate the start to kill (1 study) and the speed of flea kill (2 studies) of fluralaner. All dogs were infested prior to treatment with unfed adult C. felis fleas. Dogs in the treated groups were administered once orally with fluralaner at a minimum dose of 25 mg/kg body weight, while dogs in the control groups were not treated. Separate control and treatment groups were paired at each time point of flea assessment. Flea counts were performed by combing dogs at either 0.5, 1, 2, or 4 hours after fluralaner treatment to measure the start to kill. To evaluate the speed of flea kill over 12 weeks, flea counts were performed by combing dogs at either 4, 8, 12, or 24 hours after fluralaner treatment and then at 4, 8, 12, or 24 hours after each flea re-infestations performed at 4, 8, and 12 weeks following treatment. RESULTS: In the start to kill study, the fluralaner activity against fleas started already at 1 hour post-treatment (8% numerical efficacy). At 2 and 4 hours post-treatment, the flea reduction was significant with 36.7% and 88% efficacy, respectively. In the speed of kill studies, the efficacy against fleas after fluralaner treatment was 80.5% at 4 hours and remained ≥ 99.4% at 8, 12 and 24 hours. After flea re-infestations in weeks 4, 8 and 12, the efficacy at 4 hours was 96.8, 91.4, and 33.5%, respectively. Efficacy at 8, 12 and 24 hours after flea re-infestations was 98.0-100% for the 12 weeks of the study. Except for 4 hours after the 12-week flea re-infestation, flea reduction was significant for all time points after flea re-infestation. CONCLUSIONS: Single oral fluralaner administration rapidly eliminates existing flea infestations and provides excellent protection against fleas over 12 weeks following treatment.