First report of Dermatobia hominis resistant to doramectin in cattle

Conde, Mário Henrique; Borges, Dyego Gonçalves Lino; Freitas, Mariana Green de; Silva, Marcos Cabrera da; Borges, Fernando de Almeida

doi:10.1016/j.vetpar.2020.109335

Cited by 4 publications

(3 citation statements)

References 17 publications

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“…The damage caused by D. hominis larvae to the hide significantly decreases the commercial value of the leather [ 9 ]. Macrocyclic lactones have commonly been used to treat and prevent D. hominis larval infestations in cattle, but recent reports of resistance to this class of chemicals have been published [ 9 , 64 ], thereby putting more pressure on farmers to consider alternative methods to control D. hominis larvae infestations. In the present study, Exzolt demonstrated a therapeutic efficacy of 97.7% within 3 days after treatment, and a persistent efficacy of > 90% was observed for up to 70 days post-treatment, as evidenced by the prevention, development and establishment of D. hominis to the larval stage and formation of nodules.…”

Section: Discussionmentioning

confidence: 99%

First report of the efficacy of a fluralaner-based pour-on product (Exzolt® 5%) against ectoparasites infesting cattle in Brazil

da Costa,

de Souza Martins,

de Almeida Borges

et al. 2023

Parasites Vectors

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Background This study describes the effectiveness of a novel active pharmaceutical ingredient, fluralaner (isoxazoline class), against important ectoparasites infesting cattle in Brazil. Methods A total of 13 studies involving a 5% fluralaner-based pour-on formulation (Exzolt 5%; further referred to as Exzolt) were conducted. Specifically, the effectiveness of this formulation was studied against Rhipicephalus microplus (6 studies), Cochliomyia hominivorax larvae (4 studies), Dermatobia hominis larvae (1 study) and Haematobia irritans flies (2 studies). Results The therapeutic efficacy of Exzolt was found to exceed 98% at 4 days post treatment (DPT), while persistent efficacy (> 90% efficacy) against repeated infestations of R. microplus was observed for up to 79 DPT. In field studies, ≥ 98% therapeutic efficacy was demonstrated at all study sites by 7 DPT, and a persistent efficacy (> 90% efficacy) was observed for 42, 49 or 56 DPT. Exzolt prevented C. hominivorax eggs from developing to the larval stage, thus mitigating the development of myiasis in cattle naturally and artificially infested with this screworm. The efficacy of Exzolt against D. hominis larvae was 98% at 3 DPT, while persistent efficacy (> 90% effectiveness) was found to last for up to 70 DPT. Against H. irritans, Exzolt showed therapeutic efficacy (≥ 90%) within the first day of treatment at both study sites, while persistent efficacy (≥ 90%) was observed for 7 DPT at one site and for 21 DPT at the other site. Conclusions Overall, the results from these studies confirm that Exzolt is therapeutically efficacious against the most important ectoparasites infesting cattle in Brazil. The novel active pharmaceutical ingredient, fluralaner, provides a new treatment option for farmers to control cattle ectoparasites, especially where there is resistance to other chemical classes. In addition, an effective control of ectoparasites will improve overall cattle health and well-being as well as production. Graphical Abstract

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Section: Discussionmentioning

confidence: 99%

First report of the efficacy of a fluralaner-based pour-on product (Exzolt® 5%) against ectoparasites infesting cattle in Brazil

da Costa,

de Souza Martins,

de Almeida Borges

et al. 2023

Parasites Vectors

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“…D. hominis é capaz de infestar humanos e o crescente uso indiscriminado de lactonas macrocíclicas pode ter contribuído para o aumento de resistência. Esse grupo, por atuar contra endoparasitoses, tem sido bastante difundido na bovinocultura (Conde et al, 2020). Avermectinas e milbemicinas, atualmente, são relatadas em muitos casos de resistência (Raynal et al, 2020;Vilela et al, 2020;Valsoni et al, 2021;Santos et al, 2022;Ferreira et al, 2022).…”

Section: Discussionunclassified

Atividade Ectoparasiticida De Uma Nova Formulação (Benzoilfenilureia + Organofosforado) Em Bovinos

HARDT,

GOMES,

MELO

et al. 2023

Ars Vet

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Os ectoparasitos Rhipicephalus microplus, Dermatobia hominis e Haematobia hominis constituem grande entrave à produtividade pecuária, fator agravado, sobretudo, pela aquisição de resistência medicamentosa a muitos princípios ativos. Com o objetivo de minimizar esse fenômeno, foram conduzidos quatro estudos clínicos com uma inédita formulação (benzoilfeniluréia + organofosforado). Para avaliação da atividade anti-ixodídica foram realizados ensaios com bovinos naturalmente e experimentalmente infestados. No primeiro, o índice de eficácia carrapaticida foi superior a 90% do 7º ao 28º DPT (Dias pós-tratamento). No “Stall test” (infestações artificiais), índice máximo de eficácia (100%) foi alcançado do 20º ao 47º DPT. A atividade mosquicida da nova formulação contra Haematobia irritans (infestação natural) manteve-se superior a 90% do 1º ao 14º DPT. Sobre larvas de Dermatobia hominis, observou-se efetividade superior a 90% do 7º ao 21º DPT. Pelos resultados obtidos nos quatro estudos realizados, pode-se recomendar a inédita formulação, na dose e via empregadas, no tratamento e controle de parasitos externos de bovinos.

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“…The intensification of sheep farming and emergence of drug-resistant parasites have brought new challenges regarding the prophylaxis and treatment of small ruminant parasitism. Frequent cases of anthelmintic resistance have been reported ( 12 – 14 ) as well as ectoparasites, such as Dermatobia hominis ( 15 , 16 ), Rhipicephalus microplus ( 17 ) and Cochliomyia hominivorax ( 18 ), with resistance to the treatments with macrocyclic lactones. For this reason, the aim of this work was to verify whether closantel and ivermectin that have been used for decades are still effective in sheep naturally infested with O. ovis .…”

Section: Introductionmentioning

confidence: 99%

Prophylactic Effects of Ivermectin and Closantel Treatment in the Control of Oestrus ovis Infestation in Sheep

et al. 2022

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The sheep nasal bots Oestrus ovis is parasite of the nasal cavities and sinuses of small ruminants causing oestrosis, one of the most frequent parasitic diseases in sheep and goats. The widely use of ivermectin and closantel by the sheep breeders in the treatment and prophylaxis of gastrointestinal nematodes resulted in widespread cases of anthelmintic resistance. However, there is no report about cases of O. ovis with drug-resistance. In this study, we evaluated the prophylactics and therapeutic effects of both antiparasitics in sheep with O. ovis natural infestation. The trial was carried out from early December 2019 to March 2020, with 30 crossbred males lambs allocated into three groups of 10 animals each: control (without treatment), treated with ivermectin (0.2 mg/kg subcutaneously) and treated with closantel (10 mg/kg orally). The animals were kept together grazing the same pasture area. The treatment groups were drenched in two occasions 70 days apart: on 5th December 2019 and on 13th February 2020. On 19th March 2020, all lambs were slaughtered. The lamb heads were removed and sectioned along their longitudinal and sagittal axis to search for larvae. Recovered O. ovis larvae were counted and identified according to their developmental stage (L1, L2, and L3). Seven of the control lambs were infested with O. ovis larvae ranging from six to 17 larvae (11.6 mean infestation intensity). All recovered larvae from control group were intact and active. Three animals treated with ivermectin had O. ovis larvae (1–3 larvae), however they were dead and in degeneration. The animals treated with closantel did not have any larvae. The clinical suggestive signs of oestrosis were scarce over the experimental period. The averages of daily weight gain were similar (p > 0.05) among groups. Closantel and ivermectin had high efficacy against oestrosis and O. ovis parasitism did not hinder the performance of lambs.

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First report of Dermatobia hominis resistant to doramectin in cattle

Cited by 4 publications

References 17 publications

First report of the efficacy of a fluralaner-based pour-on product (Exzolt® 5%) against ectoparasites infesting cattle in Brazil

First report of the efficacy of a fluralaner-based pour-on product (Exzolt® 5%) against ectoparasites infesting cattle in Brazil

Atividade Ectoparasiticida De Uma Nova Formulação (Benzoilfenilureia + Organofosforado) Em Bovinos

Prophylactic Effects of Ivermectin and Closantel Treatment in the Control of Oestrus ovis Infestation in Sheep

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