Ignite Creation Date:
2025-12-25 @ 12:41 AM
Ignite Modification Date:
2026-02-26 @ 6:52 AM
Study NCT ID:
NCT02876367
Status:
COMPLETED
Last Update Posted:
2021-09-29
First Post:
2016-08-18
Is NOT Gene Therapy:
True
Has Adverse Events:
False
Brief Title:
The Clinical Epidemiology of Scrub Typhus in Humans, Chiggers and Rodents
Sponsor:
Organization:
Raw JSON
{'hasResults': False, 'derivedSection': {'miscInfoModule': {'versionHolder': '2025-12-24'}, 'conditionBrowseModule': {'meshes': [{'id': 'D012612', 'term': 'Scrub Typhus'}], 'ancestors': [{'id': 'D012288', 'term': 'Rickettsiaceae Infections'}, {'id': 'D016905', 'term': 'Gram-Negative Bacterial Infections'}, {'id': 'D001424', 'term': 'Bacterial Infections'}, {'id': 'D001423', 'term': 'Bacterial Infections and Mycoses'}, {'id': 'D007239', 'term': 'Infections'}, {'id': 'D000079426', 'term': 'Vector Borne Diseases'}]}}, 'protocolSection': {'designModule': {'bioSpec': {'retention': 'SAMPLES_WITHOUT_DNA', 'description': 'Group 1: 10 ml of blood will be collected from the participant.\n\nGroup 2: 0.2 ml of blood will be collected from the participant.'}, 'studyType': 'OBSERVATIONAL', 'designInfo': {'timePerspective': 'PROSPECTIVE', 'observationalModel': 'COHORT'}, 'enrollmentInfo': {'type': 'ESTIMATED', 'count': 1200}, 'patientRegistry': False}, 'statusModule': {'overallStatus': 'COMPLETED', 'startDateStruct': {'date': '2016-09-01', 'type': 'ACTUAL'}, 'expandedAccessInfo': {'hasExpandedAccess': False}, 'statusVerifiedDate': '2021-09', 'completionDateStruct': {'date': '2018-12-31', 'type': 'ACTUAL'}, 'lastUpdateSubmitDate': '2021-09-28', 'studyFirstSubmitDate': '2016-08-18', 'studyFirstSubmitQcDate': '2016-08-22', 'lastUpdatePostDateStruct': {'date': '2021-09-29', 'type': 'ACTUAL'}, 'studyFirstPostDateStruct': {'date': '2016-08-23', 'type': 'ESTIMATED'}, 'primaryCompletionDateStruct': {'date': '2018-04-10', 'type': 'ACTUAL'}}, 'outcomesModule': {'primaryOutcomes': [{'measure': 'determine the diversity of O. tsutsugamushi genotypes infecting rodents and mites and link these to their geographical distribution and associated habitat characteristics.', 'timeFrame': 'up to 24 months'}, {'measure': 'Correlate the frequency of O. tsutsugamushi in mites and rodents with habitat characteristics, to define interactions between distribution and transmission dynamics.', 'timeFrame': 'up to 24 months'}, {'measure': 'Identify key mite vectors and rodent hosts involved in scrub typhus natural history, human infection, and disease virulence', 'timeFrame': 'up to 24 months'}], 'secondaryOutcomes': [{'measure': 'Determine changes in scrub typhus antibody titres over time and identify acutely infected scrub typhus cases', 'timeFrame': 'up to 24 months'}, {'measure': 'Identify human-derived O. tsutsugamushi genotypes to define genomic relationships between human, rodent and mite-derived genotypes.', 'timeFrame': 'up to 24 months'}, {'measure': 'Identify putative determinants of human infection/virulence', 'timeFrame': 'up to 24 months'}, {'measure': 'To interlink the distribution of O. tsutsugamushi positive mites, rodents and humans with habitat characteristics to propose interventions to reduce the risk of human disease.', 'timeFrame': 'up to 24 months'}]}, 'oversightModule': {'oversightHasDmc': False}, 'conditionsModule': {'keywords': ['Epidemiology'], 'conditions': ['Scrub Typhus']}, 'descriptionModule': {'briefSummary': "This study to collect and identify rodents and mites across transects through diverse habitats used by the human community from a localised area identified as a scrub typhus 'hot spot'.", 'detailedDescription': 'Study design:\n\nThe project will undertake a detailed investigation of one human community, and its environment, at risk of scrub typhus:\n\nChiggers, Rodents \\& Habitat Study:\n\nTransects across diverse habitats determining spatial distribution of species of chiggers and rodents. This will be performed 3x/year.\n\nHigh-resolution habitat mapping. Comparison of genomes of O. tsutsugamushi detected in different environments, using attempted WGS.\n\nVillage Cohort Study:\n\nFollow a cohort of villagers over 2 years screening all febrile patients for scrub typhus and determining seroconversion rates and infecting O. tsutsugamushi genotypes.\n\nProcedures:\n\n* Mites:\n\nWorking with ecology/GIS collaborators, the environment of the community will be mapped and transects laid across the diverse habitats used by the community. Free-living mites will be collected with black plastic plates and black cloth21, from soil using Berlese funnels and from rodents. Trombiculid mites will be identified to genus and a subset to species.\n\nDNA will be extracted from individual chiggers, and qPCR screening for O. tsutsugamushi-positivity performed (real-time PCR targeting 47kDa-gene). A proportion of confirmed positives will undergo genotyping by attempted whole-genome sequencing (WGS).\n\n* Rodents:\n\nRodents will be captured alive along transects and identified in collaboration with University of Montpellier24. All mites will be removed from rodents, the rodents killed and the rodent spleen and liver collected for O. tsutsugamushi qPCR screening. A proportion of O. tsutsugamushi-positive samples will undergo genotyping by attempted WGS or extended MLST analysis.\n\n* Human cohort:\n\nAll those in the community (\\>10 years old) will be approached and asked for consent to participate. All enrolled will have scrub typhus ELISA/IFA (from finger-prick filter paper blood spots) performed every 4 months over 2 years to estimate the rates and dynamics of seroconversion. A brief questionnaire will be administered at each visit to determine whether the participant had a febrile illness in the preceding 4 months.\n\nPatients presenting with a febrile illness to local healthcare facilities will be clinically assessed and an on-site scrub typhus IgM rapid diagnostic test (RDT) performed. RDT positive patients will be recruited into the study, and paired acute/convalescent samples sent to LOMWRU for ELISA, qPCR and BSL3 culture, followed by genotyping by attempted WGS. A questionnaire will be administered to recruited patients to determine symptomatology and vital signs recorded.\n\nEpidemiology \\& Ecology:\n\nThe exact sample collection locations and habitat details will be recorded.\n\nGenomic analyses:\n\nTo characterize the relationships between highly diverse O. tsutsugamushi genotypes in multiple strain/genotype-infected hosts a proportion of qPCR positives (approx. 480 samples) will be analysed by whole-genome sequencing at WTCHG in Oxford.'}, 'eligibilityModule': {'sex': 'ALL', 'stdAges': ['CHILD', 'ADULT', 'OLDER_ADULT'], 'minimumAge': '10 Years', 'samplingMethod': 'NON_PROBABILITY_SAMPLE', 'studyPopulation': 'Group 1 Male or Female, aged 10 years or above, presenting with a fever\n\nGroup 2 Male or Female, aged 10 years or above, living in an identified scrub typhus environment', 'healthyVolunteers': True, 'eligibilityCriteria': 'Inclusion Criteria:\n\nAcute scrub typhus (Group 1)\n\n1. Presenting with fever \\>38 C and testing positive by scrub typhus RDT.\n2. Male or Female, aged 10 years or above.\n3. Participant is willing and able to give informed consent for participation in the study.\n\nScrub typhus serosurvey (Group 2)\n\n1. Villagers living in an environment in which scrub typhus is known to be present, who are asymptomatic.\n2. Male or Female, aged 10 years or above.\n3. Participant is willing and able to give informed consent for participation in the study.\n\nExclusion Criteria:\n\nAcute scrub typhus (Group 1)\n\n1. Villagers/patients under 10 years of age.\n2. Those unwilling to give written informed consent.\n\nScrub typhus serosurvey (Group 2)\n\n1. Villagers/patients under 10 years of age.\n2. Those unwilling to give written informed consent.'}, 'identificationModule': {'nctId': 'NCT02876367', 'briefTitle': 'The Clinical Epidemiology of Scrub Typhus in Humans, Chiggers and Rodents', 'organization': {'class': 'OTHER', 'fullName': 'University of Oxford'}, 'officialTitle': 'The Clinical Epidemiology of Scrub Typhus in Humans, Chiggers and Rodents', 'orgStudyIdInfo': {'id': 'OxTREC no. 48-15'}}, 'armsInterventionsModule': {'armGroups': [{'label': 'Acute scrub typhus (Group 1)', 'description': 'Participants presenting with a fever will be verbally consented for a scrub typhus RDT, using \\<1ml of blood that is likely to be taken as part of routine clinical assessment. If the RDT tests positive, the patient will be informed about the study and asked to give written informed consent. If they agree to join the study, participants will be asked to give a further blood sample of 10mls (2 teaspoons) for ELISA, PCR and culture testing to confirm the presence of scrub typhus.'}, {'label': 'Scrub typhus serosurvey (Group 2)', 'description': 'Villagers who are living in an identified scrub typhus environment will be informed about the study and asked to give written informed consent. If they agree to join the study they will be asked to give a finger prick dried blood spot (DBS) test on which scrub typhus ELISA and IFA will be performed.'}]}, 'ipdSharingStatementModule': {'ipdSharing': 'YES'}, 'sponsorCollaboratorsModule': {'leadSponsor': {'name': 'University of Oxford', 'class': 'OTHER'}, 'collaborators': [{'name': 'Mahidol Oxford Tropical Medicine Research Unit', 'class': 'OTHER'}, {'name': 'Lao-Oxford-Mahosot Hospital Wellcome Trust Research Unit', 'class': 'OTHER'}, {'name': 'Wellcome Trust', 'class': 'OTHER'}, {'name': 'Centre National de la Recherche Scientifique, France', 'class': 'OTHER'}], 'responsibleParty': {'type': 'SPONSOR'}}}}