Evidence map›Paper›PMID 42310702›Full record

ArticleParasites & vectors2026

Overcoming doramectin failure: field efficacy of pour-on 5% fluralaner and an experimental 1% oral formulation for the prevention of Cochliomyia hominivorax-associated umbilical myiasis in newborn calves.

Murilo Damasceno Brunet de Freitas, Daniel de Castro Rodrigues, Pablo Eduardo Martins de Paiva, Siddartha Torres, Fernando de Almeida Borges

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Article in Parasites & vectors, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

5 authors.

Murilo Damasceno Brunet de FreitasParasitic Diseases Laboratory, Faculty of Veterinary Medicine and Animal Science, Federal University of Mato Grosso do Sul, Av. Senador Filinto Müller, 2443, Campo Grande, MS, Brazil. murilo_d_b_freitas@ufms.br.ORCID http://orcid.org/0009-0000-5757-8119
Daniel de Castro RodriguesMSD Animal Health, São Paulo, SP, Brazil.ORCID http://orcid.org/0000-0001-9792-5744
Pablo Eduardo Martins de PaivaMSD Animal Health, São Paulo, SP, Brazil.
Siddartha TorresMerck Animal Health, 2 Giralda Farms, Madison, NJ, 07940, USA.ORCID http://orcid.org/0000-0003-3315-894X
Fernando de Almeida BorgesParasitic Diseases Laboratory, Faculty of Veterinary Medicine and Animal Science, Federal University of Mato Grosso do Sul, Av. Senador Filinto Müller, 2443, Campo Grande, MS, Brazil.ORCID http://orcid.org/0000-0002-8888-6269

Funding

Coordination for the Advancement of Higher Education Personnel - Brazil (CAPES) 001National Council for Scientific and Technological Development (CNPq), Brazil 304520/2024-1
6 · The paper itself

Abstract

backgroundMyiasis caused by Cochliomyia hominivorax larvae is a reemerging challenge in the Americas due to the recent reappearance of this species in areas where it had been eradicated and reports of doramectin inefficacy, despite its recognition as the most effective avermectin for prevention in cattle. As an alternative, 5% fluralaner administered via pour-on has shown 100% efficacy in the treatment and prevention of myiasis. Therefore, this study aimed to evaluate the efficacy of three antiparasitic treatments, namely 1% doramectin administered subcutaneously, 5% fluralaner pour-on, and 1% fluralaner administered orally, in preventing umbilical myiasis caused by C. hominivorax in newborn calves.

methodsThe study was conducted on a commercial beef cow-calf farm in Brazil. On day 0, during umbilical care, 200 newborn calves were randomly allocated to 4 groups: negative untreated control; 1% doramectin subcutaneously (200 µg/kg); 5% fluralaner pour-on (2.5 mg/kg); and 1% fluralaner orally (0.5 mg/kg, experimental formulation). All umbilical stumps were disinfected with 10% iodine tincture (10-30 s) without larvicidal compounds. Umbilical sites were evaluated on days 3, 7, and 14 for the presence of C. hominivorax larvae and lesion scores (0-3).

resultsThe results showed marked differences among treatments in the prevention of umbilical myiasis. In the control group, myiasis occurrence was 26% (95% CI 15-39%), confirming the high field risk of the disease. Treatment with 1% doramectin did not reduce (P = 0.8153) myiasis occurrence (22%; 95% CI 12.7-35.2%), showing a relative risk reduction of only 15.4%. Pour-on 5% fluralaner reduced myiasis occurrence to 4% (95% CI 1.1-13.4%), corresponding to a preventive efficacy of 84.6%. Despite proven 100% fluralaner efficacy, maternal licking may have contributed to the removal of the pour-on product in newborn calves, potentially reducing skin residues and being associated with the occurrence of umbilical myiasis. Orally administered 1% fluralaner showed 100% preventive efficacy. Umbilical lesion scores corroborated these findings, with a predominance of score 0 in fluralaner-treated groups.

conclusionsDoramectin was ineffective in preventing umbilical myiasis in newborn calves, whereas orally administered fluralaner showed 100% preventive efficacy. Pour-on fluralaner did not achieve complete preventive efficacy, possibly due to maternal licking at the product application site in calves.

Indexed as

CalliphoridaeCattle DiseasesInsecticidesIsoxazolesIvermectinMyiasisUmbilicusAdministration, OralAnimalsAnimals, NewbornAntiparasitic AgentsBrazilCattleInjections, SubcutaneousLarvaA1443 compoundAntiparasitic AgentsdoramectinInsecticidesIsoxazolesIvermectinAvermectinsCattleIsoxazolinesNew World screwworm

Identifiers

PMID42310702
PMCPMC13520140

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.