{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,1]],"date-time":"2026-06-01T19:14:28Z","timestamp":1780341268146,"version":"3.54.1"},"reference-count":32,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2024,3,28]],"date-time":"2024-03-28T00:00:00Z","timestamp":1711584000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Autonomous University of Mexico","award":["IN222913"],"award-info":[{"award-number":["IN222913"]}]},{"name":"National Autonomous University of Mexico","award":["IG202013"],"award-info":[{"award-number":["IG202013"]}]},{"name":"National Autonomous University of Mexico","award":["IN216316"],"award-info":[{"award-number":["IN216316"]}]},{"name":"National Autonomous University of Mexico","award":["IN202320"],"award-info":[{"award-number":["IN202320"]}]},{"name":"National Autonomous University of Mexico","award":["320415"],"award-info":[{"award-number":["320415"]}]},{"DOI":"10.13039\/501100003141","name":"National Council of Humanities Science and Technology (CONAHCyT) \u201cParadigms and Controversies of Science 2022\u201d","doi-asserted-by":"publisher","award":["IN222913"],"award-info":[{"award-number":["IN222913"]}],"id":[{"id":"10.13039\/501100003141","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003141","name":"National Council of Humanities Science and Technology (CONAHCyT) \u201cParadigms and Controversies of Science 2022\u201d","doi-asserted-by":"publisher","award":["IG202013"],"award-info":[{"award-number":["IG202013"]}],"id":[{"id":"10.13039\/501100003141","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003141","name":"National Council of Humanities Science and Technology (CONAHCyT) \u201cParadigms and Controversies of Science 2022\u201d","doi-asserted-by":"publisher","award":["IN216316"],"award-info":[{"award-number":["IN216316"]}],"id":[{"id":"10.13039\/501100003141","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003141","name":"National Council of Humanities Science and Technology (CONAHCyT) \u201cParadigms and Controversies of Science 2022\u201d","doi-asserted-by":"publisher","award":["IN202320"],"award-info":[{"award-number":["IN202320"]}],"id":[{"id":"10.13039\/501100003141","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003141","name":"National Council of Humanities Science and Technology (CONAHCyT) \u201cParadigms and Controversies of Science 2022\u201d","doi-asserted-by":"publisher","award":["320415"],"award-info":[{"award-number":["320415"]}],"id":[{"id":"10.13039\/501100003141","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>Leptospirosis is a neglected zoonotic disease that commonly affects cattle, pigs, horses, and dogs in many countries. Infection in dogs is usually subclinical, but acute cases of leptospirosis may occur along with systemic failure, which may become fatal. After recovery from an acute infection, dogs may become asymptomatic carriers and shed pathogenic leptospires through urine for long periods of time. Here, a study of ten different cases of leptospirosis is presented, showing the relevance of dogs as asymptomatic carriers of pathogenic Leptospira. The diagnosis was confirmed via isolation and further serological and genetic identification. Four Leptospira isolates (LOCaS28, 31, 34, and 46) were obtained from the kidneys and urine samples of 58 dogs destined for destruction (6.89%) at a Canine Control Center in Mexico City. No spirochetes were observed in the urine samples of those Leptospira-positive dogs examined under dark-field microscopy, and no clinical signs of disease were observed either. Six additional isolates were obtained: two came from asymptomatic carrier dogs (CEL60 and UADY22); another isolate came from an asymptomatic dog that was a pack companion of a clinically ill dog with fatal leptospirosis (AGFA24); and finally, three isolates were taken from dogs that died of leptospirosis (LOCaS59, Citlalli, and Nayar1). Nine out of the ten isolates were identified as being from the serogroup Canicola via cross-absorption MAT using reference strains and specific antisera, and their identity was genetically confirmed as Canicola ST34 via multi-locus sequencing typing (MLST). In contrast, the isolate Nayar1 was identified as serovar Copenhageni ST2. Interestingly, the asymptomatic dogs from which Leptospira isolates were recovered consistently showed high antibody titers in the microscopic agglutination test (MAT), revealing values of at least 1:3200 against serogroup Canicola and lower titer values against other serogroups. Isolates showed different virulence levels in the hamster model. Taken as a whole, all these findings confirmed that dogs may act as asymptomatic carriers of pathogenic leptospires and possibly spread them out to the environment, thus representing an active public health risk. The results also showed that the Canicola ST34 clone is the most prevalent Leptospira serovar in dogs in Mexico, and finally that the old-fashioned MAT is a good alternative for the detection of presumptive Leptospira asymptomatic carrier dogs.<\/jats:p>","DOI":"10.3390\/microorganisms12040674","type":"journal-article","created":{"date-parts":[[2024,3,28]],"date-time":"2024-03-28T12:52:12Z","timestamp":1711630332000},"page":"674","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["The Presence of a Virulent Clone of Leptospira interrogans Serovar Canicola in Confirmed Cases of Asymptomatic Dog Carriers in Mexico"],"prefix":"10.3390","volume":"12","author":[{"given":"Carlos Alfredo","family":"Carmona Gasca","sequence":"first","affiliation":[{"name":"Functional Biology Laboratory, Academic Unit for Veterinary Medicine and Zootechnics, Autonomous University of Nayarit, Tepic 63155, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sergio","family":"Mart\u00ednez Gonz\u00e1lez","sequence":"additional","affiliation":[{"name":"Functional Biology Laboratory, Academic Unit for Veterinary Medicine and Zootechnics, Autonomous University of Nayarit, Tepic 63155, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Luz Olivia","family":"Castillo S\u00e1nchez","sequence":"additional","affiliation":[{"name":"Functional Biology Laboratory, Academic Unit for Veterinary Medicine and Zootechnics, Autonomous University of Nayarit, Tepic 63155, Mexico"},{"name":"Leptospira and Leptospirosis Research Group, Teaching, Research and Extension Center for Animal Husbandry in the Plateau, School of Veterinary Medicine and Zootechnics, National Autonomous University of Mexico, Tequisquiapan 76795, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ernesto Armando","family":"Rodr\u00edguez Reyes","sequence":"additional","affiliation":[{"name":"Postgraduate Studies Division, School of Medicine, National Autonomous University of Mexico, Coyoacan 04510, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2800-4591","authenticated-orcid":false,"given":"Mar\u00eda Fidelia","family":"C\u00e1rdenas Marrufo","sequence":"additional","affiliation":[{"name":"School of Medicine, Autonomous University of Yucatan, Merida 97000, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ignacio","family":"Vado Sol\u00eds","sequence":"additional","affiliation":[{"name":"School of Medicine, Autonomous University of Yucatan, Merida 97000, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Giselle","family":"Casta\u00f1eda Miranda","sequence":"additional","affiliation":[{"name":"Leptospira and Leptospirosis Research Group, Teaching, Research and Extension Center for Animal Husbandry in the Plateau, School of Veterinary Medicine and Zootechnics, National Autonomous University of Mexico, Tequisquiapan 76795, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lilia Patricia","family":"L\u00f3pez Huitrado","sequence":"additional","affiliation":[{"name":"Academic Unit for Veterinary Medicine and Zootechnics, Autonomous University of Zacatecas, Zacatecas 98068, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alejandro","family":"de la Pe\u00f1a-Moctezuma","sequence":"additional","affiliation":[{"name":"Leptospira and Leptospirosis Research Group, Teaching, Research and Extension Center for Animal Husbandry in the Plateau, School of Veterinary Medicine and Zootechnics, National Autonomous University of Mexico, Tequisquiapan 76795, Mexico"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,3,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Thibeaux, R., Girault, D., Bierque, E., Soupe-Gilbert, M.E., Rettinger, A., Douyere, A., Meyer, M., Iraola, G., Picardeau, M., and Goarant, C. (2018). Biodiversity of environmental Leptospira: Improving identification and revisiting the diagnosis. Front. Microbiol., 9.","DOI":"10.3389\/fmicb.2018.00816"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Vincent, A.T., Schiettekatte, O., Goarant, C., Neela, V.K., Bernet, E., Thibeaux, R., Ismail, N., Mohd Khalid, M.K.N., Amran, F., and Masuzawa, T. (2019). Revisiting the taxonomy and evolution of pathogenicity of the genus Leptospira through the prism of genomics. PLoS Negl. Trop. Dis., 13.","DOI":"10.1371\/journal.pntd.0007270"},{"key":"ref_3","first-page":"65","article-title":"Leptospirosis in humans","volume":"387","author":"Haake","year":"2015","journal-title":"Curr. Top. Microbiol. Immunol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"105","DOI":"10.31128\/AFP-07-17-4286","article-title":"Leptospirosis: An important zoonosis acquired through work, play and travel","volume":"47","author":"Lau","year":"2018","journal-title":"Aust. J. Gen. Pr."},{"key":"ref_5","first-page":"99","article-title":"Animal leptospirosis","volume":"387","author":"Ellis","year":"2015","journal-title":"Curr. Top. Microbiol. Immunol."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Prescott, J.F., Rycroft, A.N., Boyce, J.D., MacInnes, J.I., Van Immerseel, F., and V\u00e1zquez-Boland, J.A. (2022). Pathogenesis of Bacterial Infections in Animals, John Wiley & Sons, Inc.","DOI":"10.1002\/9781119754862"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.actatropica.2008.07.005","article-title":"Carriage of Leptospira interrogans among domestic rats from an urban setting highly endemic for leptospirosis in Brazil","volume":"108","author":"Calderwood","year":"2008","journal-title":"Acta Trop."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1088","DOI":"10.4269\/ajtmh.17-0114","article-title":"Continuous excretion of Leptospira borgpetersenii Ballum in mice assessed by viability Quantitative Polymerase Chain Reaction","volume":"97","author":"Bierque","year":"2017","journal-title":"Am. J. Trop. Med. Hyg."},{"key":"ref_9","unstructured":"Megna, M. (2023, December 18). Pet Ownership Statistics Forbes. Available online: https:\/\/www.forbes.com\/advisor\/pet-insurance\/pet-ownership-statistics\/#sources_section."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1017\/S1466252321000190","article-title":"Canine leptospirosis in stray and sheltered dogs: A systematic review","volume":"23","author":"Costa","year":"2022","journal-title":"Anim. Health Res. Rev."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1111\/jsap.12328","article-title":"European consensus statement on leptospirosis in dogs and cats","volume":"56","author":"Schuller","year":"2015","journal-title":"J. Small Anim. Pr."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1966","DOI":"10.1111\/jvim.16903","article-title":"Updated ACVIM consensus statement on leptospirosis in dogs","volume":"37","author":"Sykes","year":"2023","journal-title":"J. Vet. Intern. Med."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1089\/vbz.2021.0065","article-title":"Carrier status of Leptospira spp. in healthy companion dogs in Sri Lanka","volume":"22","author":"Athapattu","year":"2022","journal-title":"Vector Borne Zoonotic Dis."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"Unit 12E 15","DOI":"10.1002\/9780471729259.mc12e05s32","article-title":"Leptospirosis serodiagnosis by the microscopic agglutination test","volume":"32","author":"Goris","year":"2014","journal-title":"Curr. Protoc. Microbiol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"495","DOI":"10.1128\/jcm.28.3.495-503.1990","article-title":"Rapid and simple method for purification of nucleic acids","volume":"28","author":"Boom","year":"1990","journal-title":"J. Clin. Microbiol."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Ahmed, N., Devi, S.M., Valverde Mde, L., Vijayachari, P., Machang\u2019u, R.S., Ellis, W.A., and Hartskeerl, R.A. (2006). Multilocus sequence typing method for identification and genotypic classification of pathogenic Leptospira species. Ann. Clin. Microbiol. Antimicrob., 5.","DOI":"10.1186\/1476-0711-5-28"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"11030","DOI":"10.1073\/pnas.0404206101","article-title":"Prospects for inferring very large phylogenies by using the neighbor-joining method","volume":"101","author":"Tamura","year":"2004","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"3022","DOI":"10.1093\/molbev\/msab120","article-title":"MEGA11: Molecular Evolutionary Genetics Analysis Version","volume":"38","author":"Tamura","year":"2021","journal-title":"Mol. Biol. Evol."},{"key":"ref_19","unstructured":"WHO (2003). Human Leptospirosis: Guidance for Diagnosis, Surveillance and Control, World Health Organization."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"530","DOI":"10.14202\/vetworld.2018.530-534","article-title":"Molecular detection of Leptospira spp. from canine kidney tissues and its association with renal lesions","volume":"11","author":"Dash","year":"2018","journal-title":"Vet. World"},{"key":"ref_21","first-page":"1","article-title":"History of leptospirosis and leptospira","volume":"387","author":"Adler","year":"2015","journal-title":"Curr. Top. Microbiol. Immunol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.medmal.2012.11.005","article-title":"Diagnosis and epidemiology of leptospirosis","volume":"43","author":"Picardeau","year":"2013","journal-title":"Med. Mal. Infect."},{"key":"ref_23","unstructured":"Weese, J.S. (2007). Infectious Diseases of the Dog and Cat, Elsevier."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"270","DOI":"10.1196\/annals.1428.088","article-title":"Frequency and type of renal lesions in dogs naturally infected with Leptospira species","volume":"1149","year":"2008","journal-title":"Ann. NY Acad. Sci."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"736","DOI":"10.1038\/nrmicro2208","article-title":"Leptospira: The dawn of the molecular genetics era for an emerging zoonotic pathogen","volume":"7","author":"Ko","year":"2009","journal-title":"Nat. Rev. Microbiol."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"799","DOI":"10.1177\/1040638714553293","article-title":"Diagnostic features in 10 naturally occurring cases of acute fatal canine leptospirosis","volume":"26","author":"Rissi","year":"2014","journal-title":"J. Vet. Diagn. Investig."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"e00869","DOI":"10.1016\/j.heliyon.2018.e00869","article-title":"MAT cross-reactions or vaccine cross-protection: Retrospective study of 863 leptospirosis canine cases","volume":"4","author":"Triger","year":"2018","journal-title":"Heliyon"},{"key":"ref_28","first-page":"143","article-title":"Isolation and molecular characterization of Leptospira borgpetersenii serovar Ballum","volume":"16","author":"Ko","year":"2013","journal-title":"Trop. Subtrop. Agroecosystems"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Miotto, B.A., Guilloux, A.G.A., Tozzi, B.F., Moreno, L.Z., da Hora, A.S., Dias, R.A., Heinemann, M.B., Moreno, A.M., Filho, A.F.S., and Lilenbaum, W. (2018). Prospective study of canine leptospirosis in shelter and stray dog populations: Identification of chronic carriers and different Leptospira species infecting dogs. PLoS ONE, 13.","DOI":"10.1371\/journal.pone.0200384"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"426","DOI":"10.1111\/j.1939-1676.2011.0704.x","article-title":"Variability in results of the microscopic agglutination test in dogs with clinical leptospirosis and dogs vaccinated against leptospirosis","volume":"25","author":"Miller","year":"2011","journal-title":"J. Vet. Intern. Med."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"434","DOI":"10.3390\/ani4030434","article-title":"Emerging and Re-Emerging Zoonoses of Dogs and Cats","volume":"4","author":"Chomel","year":"2014","journal-title":"Animals"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Smith, A.M., Stull, J.W., and Moore, G.E. (2022). Potential drivers for the re-emergence of canine leptospirosis in the United States and Canada. Trop. Med. Infect. Dis., 7.","DOI":"10.3390\/tropicalmed7110377"}],"container-title":["Microorganisms"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-2607\/12\/4\/674\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T14:19:51Z","timestamp":1760105991000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-2607\/12\/4\/674"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,3,28]]},"references-count":32,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2024,4]]}},"alternative-id":["microorganisms12040674"],"URL":"https:\/\/doi.org\/10.3390\/microorganisms12040674","relation":{},"ISSN":["2076-2607"],"issn-type":[{"value":"2076-2607","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,3,28]]}}}