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

Abstract

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.MethodsSixteen 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.ResultsFluralaner 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.ConclusionsFluralaner 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.

Lethal and sublethal effects of fluralaner on the two‐spotted spider mites, Tetranychus urticae Koch (Acari: Tetranychidae)

“…Fluralaner has high activity towards parasitic mites on animals, such as demodectic mite ( Demodex sp.) on Shih‐Tzu Canis lupus dingo Meyer and red‐handed tamarins Saguinus midas , poultry red mite Dermanyssus gallinae in birds, and northern fowl mite Ornithonyssus sylviarum in laying hens . In addition, fluralaner also exhibits high activity towards the phytophagous mite of TSSM and has been shown to bring about 100% mortality at a concentration of 3.1 mg L −1 against fipronil‐resistant (∼ 500 mg L −1 ) TSSM …”

“…on Shih-Tzu Canis lupus dingo Meyer 18 and red-handed tamarins Saguinus midas, 19 poultry red mite Dermanyssus gallinae in birds, 20 and northern fowl mite Ornithonyssus sylviarum in laying hens. [21][22][23] In addition, fluralaner also exhibits high activity towards the phytophagous mite of TSSM and has been shown to bring about 100% mortality at a concentration of 3.1 mg L −1 against fipronil-resistant (∼ 500 mg L −1 ) TSSM. 24 As is well-known, research on the toxicological effects of fluralaner towards TSSM will enhance the ability to design and execute mite management programs.…”

Effect of oral afoxolaner on naturally occurring infestations of peacocks by the louse Goniodes pavonis

“…Prior evidence that the isoxazolines would be effective against lice was reported in a study of dogs naturally infested with the sucking louse Linognathus setosus . Several prior studies that used isoxazolines in poultry also supported the potential efficacy and safety of an isoxazoline against ectoparasites on birds …”

“…Afoxolaner (NexGard ® , Merial; Lyon, France) is an antiparasitic drug in the class of isoxazolines . The mechanism of action of the isoxazolines is inhibition of chloride channels dependent on glutamate and gamma‐aminobutyric acid (GABA) . Drugs in this class have been used successfully in exotic animals for the treatment of a variety of insect and mite infestations .…”

Production losses in laying hens during infestation with the poultry red mite Dermanyssus gallinae

“…To identify performance parameters that were impacted by the PRM infestations, it was intended to examine changes in performance after implementing a highly effective treatment to the hens. For the latter , fluralaner (Exzolt®, MSD Animal Health) was administered through the drinking water twice with a 7-day interval at a dose of 0.5 mg/kg, providing the chickens with effective blood levels for approximately 2 weeks (Brauneis et al, 2017). Fluralaner was administered in the infested as well as in the non-infested units, all at the same time.…”