{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T23:19:15Z","timestamp":1787786355068,"version":"build-2784847793"},"reference-count":14,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2026,6,17]],"date-time":"2026-06-17T00:00:00Z","timestamp":1781654400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T00:00:00Z","timestamp":1787788800000},"content-version":"vor","delay-in-days":71,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"name":"MSD Animal Health"},{"DOI":"10.13039\/501100016182","name":"Universidade Federal de Mato Grosso do Sul","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100016182","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Coordination for the Advancement of Higher Education Personnel \u2013 Brazil","award":["001"],"award-info":[{"award-number":["001"]}]},{"name":"National Council for Scientific and Technological Development (CNPq), Brazil","award":["304520\/2024-1"],"award-info":[{"award-number":["304520\/2024-1"]}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Parasites Vectors"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>\n                      Myiasis caused by\n                      <jats:italic>Cochliomyia hominivorax<\/jats:italic>\n                      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\n                      <jats:italic>C.\u00a0hominivorax<\/jats:italic>\n                      in newborn calves.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      The study was conducted on a commercial beef cow\u2013calf 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\u00a0\u00b5g\/kg); 5% fluralaner pour-on (2.5\u00a0mg\/kg); and 1% fluralaner orally (0.5\u00a0mg\/kg, experimental formulation). All umbilical stumps were disinfected with 10% iodine tincture (10\u201330\u00a0s) without larvicidal compounds. Umbilical sites were evaluated on days 3, 7, and 14 for the presence of\n                      <jats:italic>C.\u00a0hominivorax<\/jats:italic>\n                      larvae and lesion scores (0\u20133).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      The results showed marked differences among treatments in the prevention of umbilical myiasis. In the control group, myiasis occurrence was 26% (95% CI 15\u201339%), confirming the high field risk of the disease. Treatment with 1% doramectin did not reduce (\n                      <jats:italic>P<\/jats:italic>\n                      \u2009=\u20090.8153) myiasis occurrence (22%; 95% CI 12.7\u201335.2%), showing a relative risk reduction of only 15.4%. Pour-on 5% fluralaner reduced myiasis occurrence to 4% (95% CI 1.1\u201313.4%), 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.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Doramectin 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.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1186\/s13071-026-07455-5","type":"journal-article","created":{"date-parts":[[2026,6,17]],"date-time":"2026-06-17T15:16:14Z","timestamp":1781709374000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Overcoming doramectin failure: field efficacy of pour-on 5% fluralaner and an experimental 1% oral formulation for the prevention of Cochliomyia hominivorax\u2013associated umbilical myiasis in newborn calves"],"prefix":"10.1186","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0009-0000-5757-8119","authenticated-orcid":false,"given":"Murilo Damasceno Brunet","family":"de Freitas","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9792-5744","authenticated-orcid":false,"given":"Daniel de Castro","family":"Rodrigues","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pablo Eduardo Martins","family":"de Paiva","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3315-894X","authenticated-orcid":false,"given":"Siddartha","family":"Torres","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8888-6269","authenticated-orcid":false,"given":"Fernando de Almeida","family":"Borges","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,6,17]]},"reference":[{"key":"7455_CR1","unstructured":"World Organization of Animal Health (WOAH). Terrestrial Manual Online Access. Chapter 3.1.14 New World screwworm (Cochliomyia hominivorax) and Old World Screwworm (Chrysomya Bezziana). (2025)."},{"key":"7455_CR2","doi-asserted-by":"publisher","DOI":"10.1038\/s41598-025-04804-9","volume":"15","author":"UM Valdez-Espinoza","year":"2025","unstructured":"Valdez-Espinoza UM, Fadda LA, Marques R, Osorio-Olvera L, Jim\u00e9nez-Garc\u00eda D, Lira-Noriega A. The reemergence of the New World screwworm and its potential distribution in North America. Sci Rep. 2025;15:23819. https:\/\/doi.org\/10.1038\/s41598-025-04804-9.","journal-title":"Sci Rep"},{"key":"7455_CR3","doi-asserted-by":"publisher","DOI":"10.1016\/j.vetpar.2024.110384","volume":"334","author":"S Muchiut","year":"2025","unstructured":"Muchiut S, Mir\u00f3 MV, Anziani O, Nava S, Lifschitz A. Failure of doramectin and ivermectin in preventing Cochliomyia hominivorax myiasis in a subtropical region: a pharmacokinetic-pharmacodynamic study. Vet Parasitol. 2025;334:110384. https:\/\/doi.org\/10.1016\/j.vetpar.2024.110384.","journal-title":"Vet Parasitol"},{"key":"7455_CR4","doi-asserted-by":"publisher","first-page":"336","DOI":"10.1186\/s13071-023-05934-7","volume":"16","author":"AJ Costa","year":"2023","unstructured":"Costa AJ, Martins JRS, Borges FA, Vettorato LF, Barufi FB, Amaral HOA et al. First report of the efficacy of a fluralaner-based pour-on product (Exzolt\u00ae 5%) against ectoparasites infesting cattle in Brazil. Parasit Vectors. 2023;16:336. https:\/\/doi.org\/10.1186\/s13071-023-05934-7.","journal-title":"Parasit Vectors"},{"key":"7455_CR5","doi-asserted-by":"publisher","first-page":"59","DOI":"10.1016\/j.prevetmed.2013.10.006","volume":"113","author":"J Reck","year":"2014","unstructured":"Reck J, Marks FS, Rodrigues RO, Souza UA, Webster A, Leite RC et al. Does Rhipicephalus microplus tick infestation increase the risk for myiasis caused by Cochliomyia hominivorax in cattle? 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DCR, ST and PEMP are employees of MSD Animal Health.","order":3,"name":"Ethics","label":"Competing interests","group":{"name":"EthicsHeading","label":"Declarations"}}],"article-number":"364"}}