Acaricides for eradication of the tick Amblyomma variegatum in the Caribbean

Le succés d'une campagne d'éradication de la tique Amblyomma variegatum dans les Caraïbes impose l'utilisation d'acaricides efficaces, si possible rémanents, faciles d'emploi, ne necessitant pas le recours à de l'eau pour la préparation de liquides dilués, ni à des équipements coûteux pour le transport et l'application. Des test de sensibilité in vitro conduits sur des souches de Porto Rico et de Guadeloupe ainsi que l'observation de l'impact des campagnes de détiquage conduites dans les Caraïbes semblent indiquer qu'il n'y a pas dans la région de problèmes de résistance aux acaricide

Strategies for the control of Rhipicephalus microplus ticks in a world of conventional acaricide and macrocyclic lactone resistance

Infestations with the cattle tick, Rhipicephalus microplus, constitute the most important ectoparasite problem for cattle production in tropical and subtropical regions worldwide, resulting in major economic losses. The control of R. microplus is mostly based on the use of conventional acaricides and macrocyclic lactones. However, the intensive use of such compounds has resulted in tick populations that exhibit resistance to all major acaricide chemical classes. Consequently, there is a need for the development of alternative approaches, possibly including the use of animal husbandry practices, synergized pesticides, rotation of acaricides, pesticide mixture formulations, manual removal of ticks, selection for host resistance, nutritional management, release of sterile male hybrids, environmental management, plant species that are unfavourable to ticks, pasture management, plant extracts, essential oils and vaccination. Integrated tick management consists of the systematic combination of at least two control technologies aiming to reduce selection pressure in favour of acaricide-resistant individuals, while maintaining adequate levels of animal production. The purpose of this paper is to present a current review on conventional acaricide and macrocyclic lactone resistance for better understanding and control of resistant ticks with particular emphasis on R. microplus on cattle

EFFECT OF FLUMETHRIN ON HEMATOLOGICAL AND BIOCHEMICAL CHANGES IN RATS

The effect of daily oral administration of flumethrin on the blood and tissue enzyme activity in albino rats was investigated. In the present study 12 (6 female and 6 male) rats were used and divided in to two groups. The first group served as the control group; the second group received flumethrin (1% pour on formulation) at dose rate of 2 mg/kg bw orally daily for 14 days. On 15th day, animals were sacrificed and blood and liver samples were collected. Flumethrin neither altered the hemoglobin level significantly nor the blood cell counts of rats. Flumethrin significantly altered the enzymatic activity of serum and liver tissue and also the serum and tissue protein. Flumethrin leads to increased MDA level, SOD and catalase activity in liver and blood samples of rats. The present study suggests that flumethrin is having toxic effect, producing oxidative stress in animal's body

Identification of a mutation in the para-sodium channel gene of the cattle tick Rhipicephalus (Boophilus) microplus associated with resistance to synthetic pyrethroid acaricides

Resistance against synthetic pyrethroid (SP) products for the control of cattle ticks in Australia was detected in the field in 1984, within a very short time of commercial introduction. We have identified a mutation in the domain II S4-5 linker of the para-sodium channel that is associated with resistance to SPs in the cattle tick Rhipicephalus (Boophilus) microplus from Australia. The cytosine to adenine mutation at position 190 in the R. microplus sequence AF134216, results in an amino acid substitution from leucine in the susceptible strain to isoleucine in the resistant strain. A similar mutation has been shown to confer SP resistance in the whitefly, Bemisia tabaci, but has not been described previously in ticks. A diagnostic quantitative PCR assay has been developed using allele-specific Taqman® minor groove-binding (MGB) probes. Using the assay to screen field and laboratory populations of ticks showed that homozygote allelic frequencies correlated highly with the survival percentage at the discriminating concentration of cypermethrin

Evaluation and comparison of a flumethrin-imidacloprid collar and repeated monthly treatments of fipronil/(s)-methoprene to control flea, Ctenocephalides f. felis, infestations on cats for eight months

Citation: Dryden, M. W., Smith, V., Davis, W. L., Settje, T., & Hostetler, J. (2016). Evaluation and comparison of a flumethrin-imidacloprid collar and repeated monthly treatments of fipronil/(s)-methoprene to control flea, Ctenocephalides f. felis, infestations on cats for eight months. Parasites & Vectors, 9, 6. doi:10.1186/s13071-016-1575-5Background: This controlled laboratory study was designed to evaluate the efficacy of the 10 % imidacloprid/4.5 % flumethrin collar (Seresto (R), Bayer Animal Health) against fleas (Ctenocephalides f. felis) on cats, when compared to fipronil (9.8 % w/w)/(s)-methoprene (11.8 % w/w) topical spot-on formulation (Frontline (R) Plus for Cats and Kittens, Merial). Methods: Thirty cats were randomized into three groups of ten animals based on pre-treatment flea counts: Group 1: imidacloprid/flumethrin collar; Group 2: fipronil/(s)-methoprene topical spot-on and Group 3: non-treated controls. The imidacloprid/flumethrin collars were applied one time on Day 0, while the fipronil/(s)-methoprene spot-on was administered every 30 days from Day 0 through Day 210. Cats were infested with 100 fleas on study days 0, 7, 14, 29, 59, 89, 119, 149, 179, 209 and 239. All flea counts were conducted by combing to remove fleas on post-treatment days 2, 8, 15, 30, 60, 90, 120, 150, 180, 210 and 240. Results: The efficacy of the imidacloprid/flumethrin collar ranged from 98.2 to 100 % for eight months. The efficacy of fipronil/(s)-methoprene spot-on ranged from 68.2 to 99.9 %. Efficacy was 98.2 %) efficacy against fleas on cats for the entire 8 month study. Monthly applications of fipronil/(s)-methoprene (Frontline (R) Plus for Cats and Kittens, Merial) generally had high, but variable (68.2 to 99.9 %) efficacy over the course of the eight month study. Based on the very high residual efficacy achieved by the imidacloprid/flumethrin collar in this study, veterinarians should expect that this collar will control and eliminate existing flea infestations on cats and in their in-home premises as long as every flea infested host is treated

Acaricide resistance of Rhipicephalus (Boophilus) microplus in State of Mato Grosso do Sul, Brazil.

This study was conducted to obtain an epidemiological view of acaricide resistance in populations of Rhipicephalus (Boophilus) microplus in the State of Mato Grosso do Sul. Twenty-four tick samples were collected from municipalities in the State where farmers had reported concerns about resistance to or failure of tick control. These ticks were subjected to in vitro resistance detection assays using the adult immersion test (AIT). The efficacy of alpha-cypermethrin, cypermethrin and amitraz treatments on samples collected throughout the State was generally poor. AIT showed efficacy ≥ 90% from the use of DDVP + chlorfenvinphos) (20 out of 21 municipalities), dichlorvos + cypermethrin (10 out of 16 municipalities) and cypermethrin + citronella + chlorpyrifos + piperonyl butoxide (20 out of 21 municipalities). PCR assays were used to detect the presence of pyrethroid resistance-associated sodium channel gene mutation. Larvae from three different populations that had previously been diagnosed as pyrethroid-resistant, through AIT, were evaluated. The PCR assays showed that the pyrethroid resistance-associated gene mutation was absent from these three populations. This study confirms that the emergence of resistance is a constant challenge for the livestock industry, and that development of resistance continues to be a major driver for new antiparasitic drugs to be developed

Essai de la fluméthrine pour le contrôle de la tique Amblyomma variegatum dans un élevage bovin en Guadeloupe

Une expérimentation a été conduite dans un élevage de Guadeloupe pour estimer l'efficacité et la rèmanence d'un pyrèthre, la fluméthrine, administrée en bain, en aspersion et en dépôt dorsal ("Pour-on") sur la tique Amblyomma variegatum. L'efficacité est bonne; elle est même supérieure à celle d'un organophosphoré utilisé comme témoin. La rémanence, appréciée par lescaractéristiques de la ponte des femelles gorgées, est d'une dizaine de jours. L'intérêt de l'administration par dépôt dorsal est souligné (Résumé d'auteur

Controlling Ectoparasites on Welsh Organic Sheep Farms

1. Organophosphate (OP) based dips offer a broad spectrum control against all major ectoparasites in the UK. However, there is continuing controversy over the safety to dip operators and the environment. The use of OPs is prohibited by organic standards, primarily because of concerns about mammalian toxicity. 2. Organic farmers are permitted to use synthetic pyrethroids (SPs)(dip products and pour-on products) and/or macrocyclic lactones (injectable products) to treat/control ectoparasites providing a derogation has been obtained from the certifying body. 3. SPs have been shown to be considerably more toxic to aquatic organisms than OPs. The environmental impact of SPs is not limited to levels in dip but also to residues in sheep fleeces. SPs may be removed from the wool by climatic conditions and then deposited in the local environment. 4. The Environment Agency have indicated that the majority of sheep dip pollution incidents involve SP dips. Concerns have been raised that as organic farmers can only use SP based dips they may be contributing to the higher levels of SP based pollution incidents. 5. There is little information as to current practices amongst organic sheep farmers to control/treat ectoparasites or on how these farmers dispose of the spent dip. In order to address this lack of information a survey was carried out by ADAS Pwllpeiran to investigate current practices amongst sheep farmers in Wales. For comparison purposes both conventional and organic farmers were included in the survey. 6. In total, 134 questionnaires were completed with 96 completed by conventional sheep farmers and the remaining 38 being completed by either in-conversion organic farmers or fully registered organic farmers. 7. Results showed that 58% of organic farmers surveyed treated their flocks for ectoparasites compared to 67% of conventional farmers. 8. Of the organic farmers surveyed, 52.6% listed flystrike as a parasite for which they treated their flocks. This was comparable to conventional farmers where 58.3% listed flystrike. Only 21.1% of organic farmers surveyed listed scab compared to 61.5% of conventional farmers. Less than 10% of both conventional and organic farmers surveyed treated for other ectoparasites. Those who did listed lice and ticks as the main ectoparasites. 9. Despite a large percentage of conventional farmers listing scab as an ectoparasite to be treated, only 11.5% of those surveyed treated for ‘scab only’ compared to 51.0% who treated for scab in combination with other ectoparasite control. A similar pattern was seen amongst organic farmers surveyed, where only 2.6% treated for ‘scab only’ whereas 18.4% treated for scab in combination with other ectoparasite control. 10. Of the organic farmers surveyed, 36.8% treated for ‘flystrike only’ compared to 7.3% of conventional farmers. 11. Despite other ectoparasites such as lice and ticks being listed by both conventional and organic farmers neither of these two parasites were treated singly but were always treated in combination with other ectoparasites. 12. Of conventional farmers surveyed who treated for ectoparasite control, 76.1% listed plunge dipping as the preferred dipping method compared to only 22.7% of the organic farmers surveyed who treated for ectoparasites. 13. The use of pour-on products was higher amongst organic farmers with 54.5% using pour-ons as a treatment method compared to 16.5% of conventional farmers. 14. Less than 5% of the organic farmers who treated for ectoparasites used a combination of treatments compared to 19% of conventional farmers who treated for ectoparasites. 15. When asked how often they treated for ectoparasites, 54% of organic farmers treated once a year compared to 42% of conventional farmers. 27% of organic farmers treated twice a year whereas 52% of conventional farmers treated twice a year. 14% of organic farmers treated three or more times a year compared to 7% of conventional farmers. 16. All organic farmers who carried out plunge dipping operations used a SP based product however of the conventional farmers who carried out plunge dipping, 39% used an SP based product. Overall, 16% of organic farmers surveyed used an SP based dip product compared to 24% of conventional farmers surveyed. Of all conventional farmers surveyed 38% used an OP based dip product. 17. Where farmers carried out plunge dipping, 53% of conventional farmers diluted spent dip before spreading to land compared to 83% of organic farmers who carried out plunge dipping operations. Of all the farmers surveyed who carried out plunge dipping only 1 treated dip with slaked lime before spreading. 18. Of all organic farmers surveyed, 5% used a mobile dipping contractor compared to 23% of conventional farmers surveyed. 19. Where contractors were used on organic holdings they were also responsible for the disposal of spent dip. The contractor was responsible for the disposal of dip on 74% of conventional holdings using contractors for dipping. 20. On 42% of the holdings using contractors, the spent dip was removed from the farm whereas on 32% of holdings the spent dip was spread on the farm land. 26% of farmers using contractors in this survey did not know how the contractor disposed of spent dip. 21. The percentage of farmers treating their flocks for ectoparasite infestations is similar for organic (58%) and conventional (69%) sheep farmers however there is a marked difference in the species of ectoparasites treated. 22. Of the conventional farmers who treated their flocks for ectoparasites, 86% listed scab as a major parasite compared to only 36% of organic farmers who also treated their flocks for ectoparasites. 23. Overall, only 3% of the organic farmers surveyed treated their sheep specifically for scab, compared to 11% of conventional farmers surveyed. 24. Of organic farmers surveyed, 37% treated their flocks specifically for blowfly strike compared to only 7% of conventional farmers surveyed. 25. Of the conventional farmers surveyed, 51% treated their flocks for more than one ectoparasite infestations compared to 18% of organic farmers surveyed. 26. From the evidence of several of the completed survey forms some farmers appeared to be using incorrect treatment methods and some were using multiple treatment methods to treat ectoparasite infestations. The use of incorrect treatments or multiple treatments is largely a reflection of the plethora of products available and suggests a lack of understanding as to which products are appropriate and licensed for the treatment of specific ectoparasites. 27. The survey found that fewer organic sheep farmers use SP dips than conventional sheep farmers do. As there are fewer organic sheep farmers overall, there is little evidence that organic sheep farmers contribute disproportionately to the level of SP based pollution incidents. 28. Summary of Recommendations: A. A further in-depth survey would be valuable to elucidate the extent of the scab problem in the national organic flock. B. Both organic and conventional farmers have difficulty in selecting the best/ most appropriate treatment for their flocks. An educational campaign would help to remedy this problem. C. Annual training courses for certifying bodies and advisors to keep up to date with developments in research and products are recommended. D. Given the potential for SP dips to cause major environmental damage if disposed of incorrectly it is a mandatory requirement that organic farmers are licensed by EA to dispose of spent dip. Inspectors should ensure cross compliance where organic farmers are using dip. E. Certifying bodies need to consider all the available evidence as to what chemicals should be permitted to treat scab and other ectoparasites and where appropriate make alterations to the standards. F. Inspection of dips facilities and EA licence should be part of the annual inspection procedures. G. Certification bodies should collate information on dipping practices and dip disposal. H. Where a pollution incident occurs on an organic holding this should be reported to the relevant certifying body. I. Development and evaluation of IPM programmes should be assessed as a management tool to reduce use of chemical treatments whilst promoting good animal husbandry and management. IPM programmes should be incorporated with animal health plans

Traitement épicutané (pour on et spot on) du bétail contre Glossina fuscipes fuscipes en République Centrafricaine

Des traitements insecticides épicutanés de quatre troupeaux de zébus Mbororo d'une quarantaine de têtes chacun ont été effectués pendant un cycle annuel et dans les conditions de l'élevage traditionnel peul. La flumetrine (Bayticol Pour on (marque déposée)) a été appliquée toutes les 3 semaines en saison des pluies et la deltamethrine (Spot on (marque déposée)) toutes les six semaines en saison sèche. Ces essais n'ont pas eu d'impact sur les densités apparentes des populations de #Glossina fuscipes fuscipes$, bien qu'ils aient pu en affecter légèrement la structure par groupe d'âge et le comportement alimentaire. Ils n'ont pas non plus modifié le taux de transmission des trypanosomoses au bétail ni la valeur de l'hématocrite. L'intérêt de ces traitements pour lutter contre les trypanosomoses du bétail n'a pu être démontré dans ces conditions expérimentales. D'autres évaluations sont nécessaires, notamment dans le cadre d'une lutte intégrée avec le piégeage des tsé-tsé. (Résumé d'auteur