Control of two protozoal infections (Cystoisospora ohioensis and Pentatrichomonas hominis) in laboratory-bred common marmoset (Callithrix jacchus) colony

Control of two protozoal infections (Cystoisospora ohioensis and Pentatrichomonas hominis) in laboratory-bred common marmoset (Callithrix jacchus) colony | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Control of two protozoal infections (Cystoisospora ohioensis and Pentatrichomonas hominis) in laboratory-bred common marmoset (Callithrix jacchus) colony Seon Won Lee, Seon A Noh, Doeun Kim, Woonghee Lee, Kyoung-Sun Lee, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8553505/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract Background As the use of the common marmoset ( Callithrix jacchus ) expands in biomedical research, knowledge gaps persist in the management of parasitic gastrointestinal disease that can cause diarrhea and weight loss. To enable healthy husbandry and robust research outcomes, clear guidance on parasite identification and control is required. We document infections by Cystoisospora ohioensis and Pentatrichomonas hominis in a laboratory colony and evaluate an integrated control strategy. Methods Marmosets with sporadic, persistent diarrhea underwent coproparasitological examination. Diarrheic animals were treated with metronidazole (MET, 25 mg/kg) and trimethoprim–sulfamethoxazole (TS, 48 mg/kg). Fecal samples with or without oocysts or trophozoites were analyzed by 18S rRNA gene (18S rRNA) and/or mitochondrial cytochrome c oxidase subunit 1 (COI) PCR and sequencing for species identification. The entire colony was then screened by cage unit and received metaphylaxis with toltrazuril (TOL, 20 mg/kg) and tinidazole (TIN, 150 mg/kg), accompanied by environmental sanitation (cages, water-delivery systems, feeding bottles, and rooms) using water washing and sodium hypochlorite disinfection. After metaphylaxis, positive animals were re-tested and treated with MET or TS until negative. Body weights were compared before and after metaphylaxis. Results Persistent watery or hemorrhagic diarrhea sporadically occurred in 34 marmosets, and symptomatic animals were treated with MET and TS for 5–12 days. Oocysts and trophozoites were detected in 10 fecal samples from symptomatic animals. Parasites identification was performed on 14 fecal samples (10 from symptomatic and coproparasitologically positive animals, 1 from symptomatic but coproparasitologically negative, and 3 from asymptomatic animals). Two sample were identified as C. ohioensis , showing 99.1–99.8% or 99.6–99.7% sequence identity based on 18S rRNA or COI PCR and sequencing, respectively. Four samples were identified as P. hominis with 98.33–100% identity based on 18S rRNA PCR and sequencing. Colony-wide screening included all 233 animals housed in 93 cages; 216 animals received two metaphylactic doses of TOL and TIN at two-week intervals. After metaphylaxis, 12 cages remained positive for P. hominis . Thiry-seven animals from these cages were treated with MET for 7 days, and three animals required an additional 15-day MET treatments before testing negative. Body weight increased significantly after metaphylaxis ( P < 0.001). Conclusions Fecal parasite screening and deworming should be prioritized when sporadic and persistent diarrhea observed in a colony. C. ohioensis may be eliminated with a single dose of TOL administered as metaphylaxis. Although P. hominis is considered non-pathogenic, its control is recommended for maintaining colony health. It can be effectively managed through a combined approach: a single metaphylactic dose of TIN followed by individual treatment with MET for more than 5 days. Non-human primate Prophylaxis Zoonosis Hygiene Anti-protozoal agent Full Text Additional Declarations No competing interests reported. Supplementary Files SupplementaryTable.xlsx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 10 Apr, 2026 Reviews received at journal 30 Mar, 2026 Reviewers agreed at journal 28 Feb, 2026 Reviews received at journal 24 Feb, 2026 Reviewers agreed at journal 18 Feb, 2026 Reviewers invited by journal 18 Feb, 2026 Editor invited by journal 17 Feb, 2026 Editor assigned by journal 16 Jan, 2026 Submission checks completed at journal 15 Jan, 2026 First submitted to journal 15 Jan, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8553505","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":594017024,"identity":"11090a5c-c59c-4400-8fb6-a98d56c6e873","order_by":0,"name":"Seon Won Lee","email":"","orcid":"","institution":"Osong Medical Innovation Foundation","correspondingAuthor":false,"prefix":"","firstName":"Seon","middleName":"Won","lastName":"Lee","suffix":""},{"id":594017025,"identity":"1cc00a99-4586-4317-aebf-7d23b0c53120","order_by":1,"name":"Seon A Noh","email":"","orcid":"","institution":"Osong Medical Innovation 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colony","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-veterinary-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [BMC Veterinary Research](http://bmcvetres.biomedcentral.com/)","snPcode":"12917","submissionUrl":"https://submission.nature.com/new-submission/12917/3?","title":"BMC Veterinary Research","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Non-human primate, Prophylaxis, Zoonosis, Hygiene, Anti-protozoal agent","lastPublishedDoi":"10.21203/rs.3.rs-8553505/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8553505/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eAs the use of the common marmoset (\u003cem\u003eCallithrix jacchus\u003c/em\u003e) expands in biomedical research, knowledge gaps persist in the management of parasitic gastrointestinal disease that can cause diarrhea and weight loss. To enable healthy husbandry and robust research outcomes, clear guidance on parasite identification and control is required. We document infections by \u003cem\u003eCystoisospora ohioensis\u003c/em\u003e and \u003cem\u003ePentatrichomonas hominis\u003c/em\u003e in a laboratory colony and evaluate an integrated control strategy.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eMarmosets with sporadic, persistent diarrhea underwent coproparasitological examination. Diarrheic animals were treated with metronidazole (MET, 25 mg/kg) and trimethoprim\u0026ndash;sulfamethoxazole (TS, 48 mg/kg). Fecal samples with or without oocysts or trophozoites were analyzed by 18S rRNA gene (18S rRNA) and/or mitochondrial cytochrome c oxidase subunit 1 (COI) PCR and sequencing for species identification. The entire colony was then screened by cage unit and received metaphylaxis with toltrazuril (TOL, 20 mg/kg) and tinidazole (TIN, 150 mg/kg), accompanied by environmental sanitation (cages, water-delivery systems, feeding bottles, and rooms) using water washing and sodium hypochlorite disinfection. After metaphylaxis, positive animals were re-tested and treated with MET or TS until negative. Body weights were compared before and after metaphylaxis.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003ePersistent watery or hemorrhagic diarrhea sporadically occurred in 34 marmosets, and symptomatic animals were treated with MET and TS for 5\u0026ndash;12 days. Oocysts and trophozoites were detected in 10 fecal samples from symptomatic animals. Parasites identification was performed on 14 fecal samples (10 from symptomatic and coproparasitologically positive animals, 1 from symptomatic but coproparasitologically negative, and 3 from asymptomatic animals). Two sample were identified as \u003cem\u003eC. ohioensis\u003c/em\u003e, showing 99.1\u0026ndash;99.8% or 99.6\u0026ndash;99.7% sequence identity based on 18S rRNA or COI PCR and sequencing, respectively. Four samples were identified as \u003cem\u003eP. hominis\u003c/em\u003e with 98.33\u0026ndash;100% identity based on 18S rRNA PCR and sequencing. Colony-wide screening included all 233 animals housed in 93 cages; 216 animals received two metaphylactic doses of TOL and TIN at two-week intervals. After metaphylaxis, 12 cages remained positive for \u003cem\u003eP. hominis\u003c/em\u003e. Thiry-seven animals from these cages were treated with MET for 7 days, and three animals required an additional 15-day MET treatments before testing negative. Body weight increased significantly after metaphylaxis (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eFecal parasite screening and deworming should be prioritized when sporadic and persistent diarrhea observed in a colony. \u003cem\u003eC. ohioensis\u003c/em\u003e may be eliminated with a single dose of TOL administered as metaphylaxis. Although \u003cem\u003eP. hominis\u003c/em\u003e is considered non-pathogenic, its control is recommended for maintaining colony health. It can be effectively managed through a combined approach: a single metaphylactic dose of TIN followed by individual treatment with MET for more than 5 days.\u003c/p\u003e","manuscriptTitle":"Control of two protozoal infections (Cystoisospora ohioensis and Pentatrichomonas hominis) in laboratory-bred common marmoset (Callithrix jacchus) colony","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-20 19:14:55","doi":"10.21203/rs.3.rs-8553505/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-10T11:49:41+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-03-30T13:23:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"53308290897188337292570132056311011461","date":"2026-02-28T09:01:14+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-24T08:49:36+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"224388448304570538243313371303126436540","date":"2026-02-18T10:44:50+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-18T09:14:03+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-02-17T08:30:41+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-16T07:05:51+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-15T15:32:28+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Veterinary Research","date":"2026-01-15T15:23:15+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-veterinary-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [BMC Veterinary Research](http://bmcvetres.biomedcentral.com/)","snPcode":"12917","submissionUrl":"https://submission.nature.com/new-submission/12917/3?","title":"BMC Veterinary Research","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"cbef38fe-cb8d-4b68-b5c6-62d57d711f0e","owner":[],"postedDate":"February 20th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-18T04:39:44+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-20 19:14:55","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8553505","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8553505","identity":"rs-8553505","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}