{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,22]],"date-time":"2026-04-22T10:35:58Z","timestamp":1776854158713,"version":"3.51.2"},"reference-count":33,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2026,4,9]],"date-time":"2026-04-09T00:00:00Z","timestamp":1775692800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Pythiosis is a neglected infectious disease caused by the aquatic oomycete Pythium insidiosum and remains underrecognized in cattle, particularly in tropical regions. Here, we report the first molecularly confirmed outbreak of bovine pythiosis in the Amazon biome, affecting more than 400 animals raised under extensive production systems and areas with prolonged exposure to standing water. Clinically affected cattle presented ulcerative and exudative cutaneous lesions, predominantly involving the distal limbs. Given the diagnostic challenges associated with pythiosis, etiological confirmation was achieved through quantitative PCR (qPCR) targeting the internal transcribed spacer (ITS) region of P. insidiosum, providing rapid and specific molecular detection during the outbreak investigation. Therapeutic interventions were implemented as part of routine field management, including intramuscular triamcinolone combined with topical copper sulfate; this regimen was associated with clinical improvement in a substantial proportion of affected animals, though treatment efficacy was not formally evaluated. The outbreak occurred in flood-prone pastures during the rainy season, highlighting the role of aquatic environments in pathogen transmission. These findings expand the current understanding of bovine pythiosis in tropical ecosystems and underscore the importance of molecular diagnostics, outbreak surveillance, and a One Health approach for the identification and management of water-associated pathogens in livestock.<\/jats:p>","DOI":"10.3390\/pathogens15040409","type":"journal-article","created":{"date-parts":[[2026,4,10]],"date-time":"2026-04-10T07:55:12Z","timestamp":1775807712000},"page":"409","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["First Molecularly Confirmed Outbreak of Bovine Pythiosis Caused by Pythium insidiosum in the Amazon Biome"],"prefix":"10.3390","volume":"15","author":[{"given":"Janayna Barroso","family":"dos Santos","sequence":"first","affiliation":[{"name":"Instituto de Medicina Veterin\u00e1ria, Universidade Federal do Par\u00e1, Castanhal 68740-970, PA, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hanna Gabriela da Silva","family":"Oliveira","sequence":"additional","affiliation":[{"name":"Instituto de Medicina Veterin\u00e1ria, Universidade Federal do Par\u00e1, Castanhal 68740-970, PA, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1987-8190","authenticated-orcid":false,"given":"Andr\u00e9 de Medeiros Costa","family":"Lins","sequence":"additional","affiliation":[{"name":"Instituto de Medicina Veterin\u00e1ria, Universidade Federal do Par\u00e1, Castanhal 68740-970, PA, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Edson Moleta","family":"Colodel","sequence":"additional","affiliation":[{"name":"Faculdade de Medicina Veterin\u00e1ria, Universidade Federal de Mato Grosso, Cuiab\u00e1 78060-900, MT, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Agnes de Souza","family":"Lima","sequence":"additional","affiliation":[{"name":"Laborat\u00f3rio de Virologia Geral e Parasitologia, Centro de Ci\u00eancias Biol\u00f3gicas e da Natureza, Universidade Federal do Acre, Campus Universit\u00e1rio, BR 364, Km 04-Distrito Industrial, Rio Branco 69920-900, AC, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Henrique dos Anjos","family":"Bomjardim","sequence":"additional","affiliation":[{"name":"Faculdade de Medicina Veterin\u00e1ria, Universidade do Norte do Tocantins, Aragua\u00edna 77826-612, TO, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1345-5413","authenticated-orcid":false,"given":"Flavio Roberto Chaves","family":"da Silva","sequence":"additional","affiliation":[{"name":"Laborat\u00f3rio de Virologia Geral e Parasitologia, Centro de Ci\u00eancias Biol\u00f3gicas e da Natureza, Universidade Federal do Acre, Campus Universit\u00e1rio, BR 364, Km 04-Distrito Industrial, Rio Branco 69920-900, AC, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0795-3934","authenticated-orcid":false,"given":"C\u00edntia","family":"Daudt","sequence":"additional","affiliation":[{"name":"Laborat\u00f3rio de Virologia Geral e Parasitologia, Centro de Ci\u00eancias Biol\u00f3gicas e da Natureza, Universidade Federal do Acre, Campus Universit\u00e1rio, BR 364, Km 04-Distrito Industrial, Rio Branco 69920-900, AC, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6630-2293","authenticated-orcid":false,"given":"Valeria","family":"Dutra","sequence":"additional","affiliation":[{"name":"Faculdade de Medicina Veterin\u00e1ria, Universidade Federal de Mato Grosso, Cuiab\u00e1 78060-900, MT, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7711-6437","authenticated-orcid":false,"given":"Felipe Masiero","family":"Salvarani","sequence":"additional","affiliation":[{"name":"Faculdade de Medicina Veterin\u00e1ria, Universidade Federal de Mato Grosso, Cuiab\u00e1 78060-900, MT, Brazil"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,9]]},"reference":[{"key":"ref_1","first-page":"151","article-title":"Infections caused by the oomycetous pathogen Pythium insidiosum","volume":"6","author":"Mendoza","year":"1996","journal-title":"J. Mycol. Med."},{"key":"ref_2","unstructured":"Alexopoulos, C.J., Mims, C.W., and Blackwell, M. (1996). Introductory Mycology, John Wiley & Sons. [4th ed.]."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2967","DOI":"10.1128\/jcm.31.11.2967-2973.1993","article-title":"Life cycle of the human and animal oomycete pathogen Pythium insidiosum","volume":"31","author":"Mendoza","year":"1993","journal-title":"J. Clin. Microbiol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.vetmic.2010.07.019","article-title":"Pythium insidiosum: An overview","volume":"146","author":"Gaastra","year":"2010","journal-title":"Vet. Microbiol."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Yolanda, H., and Krajaejun, T. (2022). Global distribution and clinical features of pythiosis in humans and animals. J. Fungi, 8.","DOI":"10.3390\/jof8020182"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1016\/j.mmcr.2016.11.004","article-title":"Cutaneous pythiosis in calves: An epidemiologic, pathologic, serologic, and molecular characterization","volume":"14","author":"Konradt","year":"2016","journal-title":"Med. Mycol. Case Rep."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"340","DOI":"10.1590\/1678-5150-pvb-6532","article-title":"Pythiosis in cattle in Northeastern Brazil","volume":"40","author":"Maia","year":"2020","journal-title":"Pesqui. Vet. Bras."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"583","DOI":"10.1590\/S0100-736X2008001200003","article-title":"Outbreak of cutaneous pythiosis in cattle","volume":"28","author":"Gabriel","year":"2008","journal-title":"Pesqui. Vet. Bras."},{"key":"ref_9","first-page":"534","article-title":"Development of a nested PCR assay for the detection of Pythium insidiosum DNA in clinical specimens","volume":"17","author":"Grooters","year":"2003","journal-title":"J. Vet. Intern. Med."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"971","DOI":"10.1099\/jmm.0.000117","article-title":"Detection of the oomycete Pythium insidiosum by real-time PCR targeting the gene coding for exo-1,3-\u03b2-glucanase","volume":"64","author":"Keeratijarut","year":"2015","journal-title":"J. Med. Microbiol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"868","DOI":"10.1093\/mmy\/myx123","article-title":"High-resolution melting analysis: A novel approach for clade differentiation in Pythium insidiosum and pythiosis","volume":"56","author":"Worasilchai","year":"2018","journal-title":"Med. Mycol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"206","DOI":"10.1016\/j.cccn.2005.05.050","article-title":"Nucleic acid-based methods for the detection of bacterial pathogens: Present and future considerations for the clinical laboratory","volume":"363","author":"Mothershed","year":"2006","journal-title":"Clin. Chim. Acta"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1016\/j.vetmic.2012.03.030","article-title":"Phylogenetic relationships of Brazilian isolates of Pythium insidiosum based on ITS rDNA and cytochrome oxidase II gene sequences","volume":"159","author":"Azevedo","year":"2012","journal-title":"Vet. Microbiol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1203","DOI":"10.1128\/CVI.00515-09","article-title":"The 74-kilodalton immunodominant antigen of the pathogenic oomycete Pythium insidiosum is a putative exo-1,3-beta-glucanase","volume":"1","author":"Krajaejun","year":"2010","journal-title":"Clin. Vaccine Immunol."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Marengo, J.A., Souza, C.M., Thonicke, K., Burton, C., Halladay, K., Betts, R.A., Alves, L.M., and Soares, W.R. (2018). Changes in Climate and Land Use Over the Amazon Region: Current and Future Variability and Trends. Front. Earth Sci., 6.","DOI":"10.3389\/feart.2018.00228"},{"key":"ref_16","unstructured":"Intergovernmental Panel on Climate Change (IPCC) (2023). Climate Change 2023: Synthesis Report."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1083","DOI":"10.1590\/S0100-736X2011001200008","article-title":"Pythiosis in production animals in the Pantanal of Mato Grosso","volume":"31","author":"Santos","year":"2011","journal-title":"Pesqui. Vet. Bras."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1617","DOI":"10.1111\/tbed.14135","article-title":"Outbreak of equine pythiosis in a southeastern region of Brazil: Environmental isolation and phylogeny","volume":"69","author":"Paz","year":"2022","journal-title":"Transbound. Emerg. Dis."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1177\/1040638720968937","article-title":"Diseases caused by Pythium insidiosum in sheep and goats: A review","volume":"33","author":"Santurio","year":"2021","journal-title":"J. Vet. Diagn. Investig."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1016\/j.meegid.2016.11.020","article-title":"Microevolutionary analyses of Pythium insidiosum isolates of Brazil and Thailand based on exo-1,3-\u03b2-glucanase gene","volume":"48","author":"Ribeiro","year":"2017","journal-title":"Infect. Genet. Evol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"537","DOI":"10.1017\/S0953756203007718","article-title":"A molecular phylogeny of Pythium insidiosum","volume":"107","author":"Schurko","year":"2003","journal-title":"Mycol. Res."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Htun, Z.M., Laikul, A., Pathomsakulwong, W., Yurayart, C., Lohnoo, T., Yingyong, W., Kumsang, Y., Payattikul, P., Sae-Chew, P., and Rujirawat, T. (2021). Identification and biotyping of Pythium insidiosum isolated from urban and rural areas by multiplex PCR, DNA barcoding and proteomic analyses. J. Fungi, 7.","DOI":"10.3390\/jof7040242"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"767","DOI":"10.1128\/AAC.01075-07","article-title":"In vitro activities of voriconazole, itraconazole, and terbinafine alone or in combination against Pythium insidiosum isolates from Brazil","volume":"52","author":"Argenta","year":"2008","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Yolanda, H., and Krajaejun, T. (2021). History and Perspective of Immunotherapy for Pythiosis. Vaccines, 26.","DOI":"10.3390\/vaccines9101080"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Vasconcelos, A.B., Fran\u00e7a, D.A., Prado, A.C., Yamauchi, D.H., Silva, A.C.A., Barros, I.O., Valen\u00e7a, S.R.F.A., Lucheis, S.B., and Bosco, S.M.G. (2025). Molecular detection of Pythium insidiosum in cutaneous lesions of horses from Northeastern Brazil. Animals, 15.","DOI":"10.3390\/ani15192863"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1046\/j.1365-3164.2002.00296.x","article-title":"PCR-based detection of Pythium and Lagenidium DNA in frozen and ethanol-fixed animal tissues","volume":"13","author":"Znajda","year":"2002","journal-title":"Vet. Dermatol."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Sridapan, T., and Krajaejun, T. (2022). Nucleic Acid-Based Detection of Pythium insidiosum: A Systematic Review. J. Fungi, 9.","DOI":"10.3390\/jof9010027"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1016\/j.mmcr.2016.11.005","article-title":"Cutaneous pythiosis in a Red Brangus beef calf cured by immunotherapy","volume":"14","author":"Grant","year":"2016","journal-title":"Med. Mycol. Case Rep."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2969","DOI":"10.1007\/s42770-024-01435-6","article-title":"Equidae pythiosis in Brazil and the world: A systematic review of the last 63 years (1960\u20132023)","volume":"55","author":"Pereira","year":"2024","journal-title":"Braz. J. Microbiol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1016\/j.jcpa.2022.05.002","article-title":"A retrospective study of pythiosis in domestic animals in Northeastern Brazil","volume":"195","author":"Kommers","year":"2022","journal-title":"J. Comp. Pathol."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"dos Santos, J.B., and Salvarani, F.M. (2025). Impacts of Climate Change on Cattle Health and Production in the Brazilian Amazon Biome. Ruminants, 5.","DOI":"10.3390\/ruminants5040058"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1111\/avj.70054","article-title":"From plants to animals: Pythium, Lagenidium, Aphanomyces, and other oomycete pathogens of animals from a One Health perspective","volume":"104","author":"Cheung","year":"2026","journal-title":"Aust. Vet. J."},{"key":"ref_33","unstructured":"(2026). One Health synergies. Nat. Sustain., 9, 1\u20132."}],"container-title":["Pathogens"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-0817\/15\/4\/409\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,22]],"date-time":"2026-04-22T09:36:39Z","timestamp":1776850599000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-0817\/15\/4\/409"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,9]]},"references-count":33,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2026,4]]}},"alternative-id":["pathogens15040409"],"URL":"https:\/\/doi.org\/10.3390\/pathogens15040409","relation":{},"ISSN":["2076-0817"],"issn-type":[{"value":"2076-0817","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,9]]}}}