Parasiticidal combination comprising indoxacarb and deltamethrin

The invention relates to antiparasitic compositions comprising a combination of indoxacarb and deltamethrin and their use in a method to control parasite insect- and acarid- infestations on animals

Parasiticidal combination comprising indoxacarb and deltamethrin

The invention relates to antiparasitic compositions comprising a combination of indoxacarb and deltamethrin and their use in a method to control parasite insect- and acarid-infestations on animals

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

Rabbit haemorrhagic disease: experimental study of a recent highly pathogenic GI.2/RHDV2/b strain and evaluation of vaccine efficacy

[EN] In 2010, a variant of the rabbit haemorrhagic disease virus (RHDV) belonging to a new GI.2 genotype was identified in France and rapidly spread worldwide. Due to antigenic difference, new vaccines including G1.2 strains have been developed to confer adequate protection. An increase in the pathogenicity of the circulating strains was recently reported. The objective of this experimental study was to characterise the infection with a highly pathogenic GI.2/RHDV2/b isolate (2017) and assess the efficacy of Filavac VHD K C+V vaccine (Filavie) against this strain. Four and 10-wk-old specific pathogen-free rabbits were inoculated with a recommended dose of vaccine. After 7 d, controls and vaccinated rabbits were challenged and clinically monitored for 14 d. All animals were necropsied and blood, organs and urine were sampled for quantitative reverse transcription polymerase chain reaction (RT-qPCR) analysis. In adult groups, regular nasal and rectal swabbing were performed, and faeces were collected after death to monitor RNA shedding. In control groups, the challenge strain induced acute RHD between 31 and 72 h post-inoculation, with a mortality rate of 100% for kits and 89% for adult rabbits. Except for a shorter mean time to death in kits, similar clinical signs and lesions were observed between age groups. The vaccination significantly prevented all mortality, clinical signs, detection of viral RNA in serum and gross lesions in kits and adult rabbits. In adult groups, we also demonstrated that vaccine significantly protected from detectable RNA shedding via naso-conjunctival and rectal routes. Two weeks after challenge, RNA copies were not detected by PCR in the liver, spleen, lungs, kidneys, faeces and urine of vaccinated adult rabbits. The findings for kits were similar, except that very low levels of RNA were present in the liver and spleen of a few rabbits. These data show that immunisation prevented any significant viral multiplication and/or allowed a rapid clearance. We concluded that, despite the quick evolution of GI.2/RHDV2/b strains, the protection conferred by the vaccine remains adequate. In the context of coexistence of both GI.1 and GI.2 genotypes in some countries, with the circulation of multiples recombinant viruses, the vaccination should be based on the association of strains from both genotypes.Le Minor, O.; Boucher, S.; Joudou, L.; Mellet, R.; Sourice, M.; Le Moullec, T.; Nicolier, A.... (2019). Rabbit haemorrhagic disease: experimental study of a recent highly pathogenic GI.2/RHDV2/b strain and evaluation of vaccine efficacy. World Rabbit Science. 27(3):143-156. https://doi.org/10.4995/wrs.2019.11082SWORD143156273Abrantes J., van der Loo W., Le Pendu J., Esteves P.J. 2012. Rabbit haemorrhagic disease (RHD) and rabbit haemorrhagic disease virus (RHDV): a review. Vet. Res., 43: 12. https://doi.org/10.1186/1297-9716-43-12Abrantes J., Lopes A.M., Dalton K.P., Melo P., Correia J.J., Ramada M., Alves P.C., Parra F., Esteves P.J. 2013. New variant of rabbit hemorrhagic disease virus, Portugal, 2012-2013. Emerg. Infect. Dis., 19: 1900-1902. https://doi.org/10.3201/eid1911.130908Calvete C., Sarto P., Calvo A.J., Monroy F., Calvo J.H. 2014. Letter - Could the new rabbit haemorrhagic disease virus variant (RHDVb) be fully replacing classical RHD strains in the Iberian Peninsula?. World Rabbit Sci., 22: 91-91. https://doi.org/10.4995/wrs.2014.1715Calvete C, Mendoza M, Alcaraz A, Sarto M.P., Jiménez-de-Bagüéss M.P., Calvo A.J., Monroy F., Calvo J.H., 2018. Rabbit haemorrhagic disease: Cross-protection and comparative pathogenicity of GI.2/RHDV2/b and GI.1b/RHDV lagoviruses in a challenge trial. Vet. Microbiol., 219: 87-95. https://doi.org/10.1016/j.vetmic.2018.04.018Capucci L., Cavadini P., Schiavitto M., Lombardi G., Lavazza A. 2017. Increased pathogenicity in rabbit haemorrhagic disease virus type 2 (RHDV2). Vet. Rec., 180: 426. https://doi.org/10.1136/vr.104132Carvalho C.L., Duarte E.L., Monteiro M., Botelho A., Albuquerque T., Fevereiro M., Henriques A.M., Barros SS., Duarte MD. 2017. Challenges in the rabbit haemorrhagic disease 2 (RHDV2) molecular diagnosis of vaccinated rabbits. Vet. Microbiol. 198: 43-50. https://doi.org/10.1016/j.vetmic.2016.12.006Dalton K.P., Balseiro A., Juste R.A., Podadera A., Nicieza I., Del Llano D., González R., Martin Alonso J.M., Prieto J.M., Parra F., Casais R. 2018. Clinical course and pathogenicity of variant rabbit haemorrhagic disease virus in experimentally infected adult and kit rabbits: Significance towards control and spread. Vet. Microbiol., 220: 24-32. https://doi.org/10.1016/j.vetmic.2018.04.033Dalton K.P., Nicieza I., Abrantes J., Esteves P.J., Parra F., 2014. Spread of new variant RHDV in domestic rabbits on the Iberian Peninsula. Vet. Microbiol., 169: 67-73. https://doi.org/10.1016/j.vetmic.2013.12.015Dalton K.P., Nicieza I., Balseiro A., Muguerza M.A., Rosell J.M., Casais R., Álvarez Á.L., Parra F. 2012. Variant rabbit hemorrhagic disease virus in young rabbits, Spain. Emerg. Infect. Dis., 18: 2009-2012. https://doi.org/10.3201/eid1812.120341Duarte M., Henriques M., Barros S.C., Fagulha T., Ramos F., Luís T., Fevereiro M., Benevides S., Flor L., Barros S.V., Bernardo S. 2015. Detection of RHDV variant 2 in the Azores. Vet. Rec.,176: 130. https://doi.org/10.1136/vr.h497Forrester N.L., Boag B., Moss S.R., Turner S.L., Trout R.C., White P.J., Hudson P.J., Gould E.A., 2003. Long-term survival of New Zealand rabbit haemorrhagic disease virus RNA in wild rabbits, revealed by RT-PCR and phylogenetic analysis. J. Gen.Virol., 84: 3079-3086. https://doi.org/10.1099/vir.0.19213-0Gall A., Schirrmeier H. 2006. Persistence of rabbit haemorrhagic disease virus genome in vaccinated rabbits after experimental infection. J. Vet. Med. B. Infect. Dis. Vet. Public Health, 53: 358-362. https://doi.org/10.1111/j.1439-0450.2006.00986.xGall A., Hoffmann B., Teifke J.P., Lange B., Schirrmeier H., 2007. Persistence of viral RNA in rabbits which overcome an experimental RHDV infection detected by a highly sensitive multiplex real-time RT-PCR. Vet. Microbiol.,120: 17-32. https://doi.org/10.1016/j.vetmic.2006.10.006Hall R.N., Mahar J.E., Haboury S., Stevens V., Holmes E.C., Strive T. 2015. Emerging Rabbit Hemorrhagic Disease Virus 2 (RHDVb), Australia. Emerg. Infect. Dis., 21: 2276-2278. https://doi.org/10.3201/eid2112.151210Le Gall G., Boilletot E., Morisse J.P. 1992. Viral haemorrhagic disease of rabbit: purification and characterization of a strain isolated in France. Ann. Rech. Vet., 23: 381-387.Le Gall-Reculé G., Zwingelstein F., Boucher S., Le Normand B., Plassiart G., Portejoie Y., Decors A., Bertagnoli S., Guérin J.L., Marchandeau S. 2011. Detection of a new variant of rabbit haemorrhagic disease virus in France. Vet. Rec., 168: 137-138. https://doi.org/10.1136/vr.d697Le Gall-Reculé G., Lavazza A., Marchandeau S., Bertagnoli S., Zwingelstein F., Cavadini, P., Martinelli N., Lombardi G., Guérin J.L., Lemaitre E., Decors A., Boucher S., Le Normand B., Capucci L. 2013. Emergence of a new lagovirus related to Rabbit Haemorrhagic Disease Virus. Vet. Res., 44: 81. https://doi.org/10.1186/1297-9716-44-81Le Gall-Reculé G., Lemaitre E., Bertagnoli S., Hubert C., Top S., Decors A., Marchandeau S., Guitton J.S., 2017. Large-scale lagovirus disease outbreaks in European brown hares (Lepus europaeus) in France caused by RHDV2 strains spatially shared with rabbits (Oryctolagus cuniculus). Vet. Res., 48: 70. https://doi.org/10.1186/s13567-017-0473-yLe Minor O., Beilvert F., Le Moullec T., Djadour D., Martineau J. 2013. Evaluation de l'efficacité d'un nouveau vaccin contre le virus variant de la maladie hémorragique virale du lapin (VHD).15èmes Journées de la Recherche Cunicole, 19-20 novembre, Le Mans, France.Le Minor O., Joudou L., Le Moullec T., Beilvert F. 2017. Innocuité et efficacité de la vaccination à 2 et 3 semaines d'âge contre le virus RHDV2 de la maladie hémorragique virale du lapin (VHD).17èmes Journées de la Recherche Cunicole, 22-13 novembre, Le Mans, France.Le Pendu J., Abrantes J., Bertagnoli S., Guitton J.S., Le Gall-Reculé G., Lopes A.M., Marchandeau S., Alda F., Almeida T., Célio A.P., Bárcena J., Burmakina G., Blanco E., Calvete C., Cavadini P., Cooke B., Dalton K., Delibes Mateos M., Deptula W., Eden J.S., Wang F., Ferreira C.C., Ferreira P., Foronda P., Gonçalves D., Gavier-Widén D., Hall R., Hukowska-Szematowicz B., Kerr P., Kovaliski J., et al. 2017. Proposal for a unified classification system and nomenclature of lagoviruses. J. Gen. Virol., 98:1658-1666. https://doi.org/10.1099/jgv.0.000840Lopes A.M., Correia J., Abrantes J., Melo P., Ramada M., Magalhães M.J., Alves P.C., Esteves P.J. 2015. Is the new variant RHDV replacing genogroup 1 in Portuguese wild rabbit populations? Viruses, 7: 27-36. https://doi.org/10.3390/v7010027Mahar J.E., Hall R.N., Peacock D., Kovaliski J., Piper M., Mourant R., Huang N., Campbell S., Gu X., Read A., Urakova N., Cox T., Holmes E.C., Strive T. 2018. Rabbit haemorrhagic disease virus 2 (GI.2) is replacing endemic strains of RHDV in the Australian landscape within 18 months of its arrival. J. Virol., https://doi.org/10.1128/JVI.01374-17Martin-Alonso A., Martin-Carrillo N., Garcia-livia K., Valladares B., Foronda P. 2016. Emerging rabbit haemorrhagic disease virus 2 (RHDV2) at the gates of the African continent. Infect. Genet. Evol., 44: 46-50. https://doi.org/10.1016/j.meegid.2016.06.034Morin H., Le Minor O., Beilvert F., Le Moullec T. 2015. Durée d'immunité conférée par un vaccin vis-à-vis des calicivirus classique et variant de la maladie virale hémorragique. 16èmes Journées de la Recherche Cunicole, 18-19 novembre, Le mans, France.Neimanis A., Larsson Pettersson U., Huang N., Gavier‑Widén D.,Strive T. 2018. Elucidation of the pathology and tissue distribution of Lagovirus europaeus GI.2/RHDV2 (rabbit haemorrhagic disease virus 2) in young and adult rabbits (Oryctolagus cuniculus). Vet. Res., 49: 46. https://doi.org/10.1186/s13567-018-0540-zOIE, 2017. Manual of Diagnostic Tests and Vaccines for Terrestrial Animals 2017. Chapter 2.6.2. Rabbit Haemorrhagic disease. Available at: (Accessed 8 February 2018): http://www.oie.int/fileadmin/Home/fr/Health_standards/tahm/3.06.02_RHD.pdfOIE, 2016. Rabbit Haemorrhagic disease, Canada-immediate notification report. Available at: http://www.oie.int/wahis_2/public/wahid.php/Reviewreport/Review?page_refer=MapFullEventReport&reportid=20799.Puggioni G., Cavadini P., Maestrale C., Scivoli R., Botti G., Ligios C., Le Gall- Recule G., Lavazza A., Capucci L. 2013. The new French 2010 Rabbit Hemorrhagic Disease Virus causes an RHD-like disease in the Sardinian Cape hare (Lepus capensis mediterraneus). Vet. Res., 44: 96.https://doi.org/10.1186/1297-9716-44-96Read A.J., Kirkland P.D. 2017. Efficacy of a commercial vaccine against different strains of rabbit haemorrhagic disease virus. Aust. Vet. J., 95: 223-226. https://doi.org/10.1111/avj.12600Silvério D., Lopes A.M., Melo-Ferreira J., Magalhães M.J., Monterroso P., Serronha A., Maio E., Alves P.C., Esteves P.J., Abrantes J. 2018. Insights into the evolution of the new variant rabbit haemorrhagic disease virus (GI.2) and the identification of novel recombinant strains. Transbound. Emerg. Dis., 65: 983-992. https://doi.org/10.1111/tbed.12830Shien, J.H., Shieh, H.K., Lee, L.H. 2000. Experimental infections of rabbits with rabbit haemorrhagic disease virus monitored by polymerase chain reaction. Res. Vet. Sci., 68, 255-259. https://doi.org/10.1053/rvsc.1999.0372Spikey N., McCabe V.J., Greenwood N.M., Jack S.C., Sutton D., van der Waart L. 2012. Novel bivalent vectored vaccine for control of myxomatosis and rabbit haemorrhagic disease. Vet. Rec., 170: 309. https://doi.org/10.1136/vr.100366Strive T., Wright J., Kovaliski J., Botti G., Capucci L. 2010. The non-pathogenic Australian lagovirus RCV-A1 causes a prolonged infection and elicits partial crossprotection to rabbit haemorrhagic disease virus. Virology, 398, 125-134. https://doi.org/10.1016/j.virol.2009.11.045Westcott D.G., Frossard J.P., Everest D., Dastjerdi A., Duff J.P., Choudhury B. 2014. Incursion of RHDV2- like variant in Great Britain. Vet. Rec., 174: 333-333. https://doi.org/10.1136/vr.g234

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