An observational study in Scrub Typhus, sponsored by University of Oxford. Completed. Open to participants aged 10 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2021-09-29.
Sponsored by University of Oxford · Observational
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'.
Study design:
The project will undertake a detailed investigation of one human community, and its environment, at risk of scrub typhus:
Chiggers, Rodents \& Habitat Study:
Transects across diverse habitats determining spatial distribution of species of chiggers and rodents. This will be performed 3x/year.
High-resolution habitat mapping. Comparison of genomes of O. tsutsugamushi detected in different environments, using attempted WGS.
Village Cohort Study:
Follow a cohort of villagers over 2 years screening all febrile patients for scrub typhus and determining seroconversion rates and infecting O. tsutsugamushi genotypes.
Procedures:
Working 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.
DNA 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).
Rodents 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.
All 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.
Patients 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.
Epidemiology \& Ecology:
The exact sample collection locations and habitat details will be recorded.
Genomic analyses:
To 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.
University of Oxford is the lead sponsor of 812 studies on the registry; 119 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Group 1 Male or Female, aged 10 years or above, presenting with a fever
Group 2 Male or Female, aged 10 years or above, living in an identified scrub typhus environment
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Acute scrub typhus (Group 1)
Scrub typhus serosurvey (Group 2)
Exclusion Criteria:
Acute scrub typhus (Group 1)
Scrub typhus serosurvey (Group 2)
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
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.
determine the diversity of O. tsutsugamushi genotypes infecting rodents and mites and link these to their geographical distribution and associated habitat characteristics.
Time frame: up to 24 months
Correlate the frequency of O. tsutsugamushi in mites and rodents with habitat characteristics, to define interactions between distribution and transmission dynamics.
Time frame: up to 24 months
Identify key mite vectors and rodent hosts involved in scrub typhus natural history, human infection, and disease virulence
Time frame: up to 24 months
Determine changes in scrub typhus antibody titres over time and identify acutely infected scrub typhus cases
Time frame: up to 24 months
Identify human-derived O. tsutsugamushi genotypes to define genomic relationships between human, rodent and mite-derived genotypes.
Time frame: up to 24 months
Identify putative determinants of human infection/virulence
Time frame: up to 24 months
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.
Time frame: up to 24 months
No study locations are listed for this record.
Plan to share: Yes
No publications or documents are linked to this record.
This study is completed, as verified in Sep 2021. You cannot join it, but the record below documents what was studied.
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Scrub Typhus