Scrub TyphusNCT02876367
The Clinical Epidemiology of Scrub Typhus in Humans, Chiggers and Rodents
An observational study of Scrub Typhus, run by University of Oxford.
Trial summary
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'. Read more about this study
- Who is it for?
- Ages 10 years and olderHealthy volunteers can take part
- Conditions the study is for
- Scrub Typhus
- How many people
- 1,200 participants
- Where
- No sites listed yet
- Study dates
- 1 Sep 2016to 31 Dec 2018
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 10 years and older
- All sexes
- Healthy volunteers accepted
- Child, Adult, Older adult
Study population: 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
Who may be able to join
- Acute scrub typhus (Group 1)
- Presenting with fever >38 C and testing positive by scrub typhus RDT.
- Male or Female, aged 10 years or above.
- Participant is willing and able to give informed consent for participation in the study.
- Scrub typhus serosurvey (Group 2)
- Villagers living in an environment in which scrub typhus is known to be present, who are asymptomatic.
- Male or Female, aged 10 years or above.
- Participant is willing and able to give informed consent for participation in the study.
Who cannot join
- Acute scrub typhus (Group 1)
- Villagers/patients under 10 years of age.
- Those unwilling to give written informed consent.
- Scrub typhus serosurvey (Group 2)
- Villagers/patients under 10 years of age.
- Those unwilling to give written informed consent.
About this study
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'.
Read the detailed description
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:
- Mites:
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:
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.
- Human cohort:
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.
- Conditions
- Scrub Typhus
- Keywords
- Epidemiology
- Medical subject headings
- Scrub Typhus
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Acute scrub typhus (Group 1) | 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. | |
| Scrub typhus serosurvey (Group 2) | 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. |
What is being measured
The primary outcome is the main question the study is designed to answer.
determine the diversity of O. tsutsugamushi genotypes infecting rodents and mites and link these to their geographical distribution and associated habitat characteristics.
Measured: 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.
Measured: up to 24 months
Identify key mite vectors and rodent hosts involved in scrub typhus natural history, human infection, and disease virulence
Measured: up to 24 months
Secondary outcomes (4)
Determine changes in scrub typhus antibody titres over time and identify acutely infected scrub typhus cases
Measured: up to 24 months
Identify human-derived O. tsutsugamushi genotypes to define genomic relationships between human, rodent and mite-derived genotypes.
Measured: up to 24 months
Identify putative determinants of human infection/virulence
Measured: 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.
Measured: up to 24 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Aug 2016 (estimated)
- Study start1 Sep 2016
- Primary completion10 Apr 2018
- Study completion31 Dec 2018
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Scrub TyphusStudies of the same condition, open and under way.
- More trials run by University of OxfordThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 1,200 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Oxford
- Sponsor type
- University, hospital or other
- Collaborators
- Mahidol Oxford Tropical Medicine Research Unit, Lao-Oxford-Mahosot Hospital Wellcome Trust Research Unit, Wellcome Trust, Centre National de la Recherche Scientifique, France
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02876367
- Sponsor's protocol ID
- OxTREC no. 48-15
- Status last verified
- Sep 2021
- First submitted
- 18 Aug 2016
- Last updated
- 29 Sep 2021
- Results posted
- No
- Data monitoring committee
- No
- Individual data sharing
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 29 Sep 2021. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Clinical Epidemiology of Scrub Typhus in Humans, Chiggers and Rodents
- ClinicalTrials.gov ID
- NCT02876367
- Acronym / sponsor ID
- OxTREC no. 48-15
- Conditions
- Scrub Typhus
- Keywords
- Epidemiology
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 1,200 participants (estimated)
- Lead sponsor
- University of OxfordUniversity, hospital or other
- Collaborators
- Mahidol Oxford Tropical Medicine Research Unit, Lao-Oxford-Mahosot Hospital Wellcome Trust Research Unit, Wellcome Trust, Centre National de la Recherche Scientifique, France
- Study start
- 1 Sep 2016 (actual)
- Primary completion
- 10 Apr 2018 (actual)
- Study completion
- 31 Dec 2018 (actual)
- First posted
- 23 Aug 2016 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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'.
Detailed description
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:
- Mites:
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:
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.
- Human cohort:
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.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Acute scrub typhus (Group 1) | – | –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. |
| Scrub typhus serosurvey (Group 2) | – | –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. |
Who may qualify
- Ages
- 10 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult, Older adult
- Study population
- 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
Key inclusion criteria (8 listed)
- Acute scrub typhus (Group 1)
- Presenting with fever >38 C and testing positive by scrub typhus RDT.
- Male or Female, aged 10 years or above.
- Participant is willing and able to give informed consent for participation in the study.
- Scrub typhus serosurvey (Group 2)
Key exclusion criteria (6 listed)
- Acute scrub typhus (Group 1)
- Villagers/patients under 10 years of age.
- Those unwilling to give written informed consent.
- Scrub typhus serosurvey (Group 2)
- Villagers/patients under 10 years of age.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
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
4 secondary outcomes
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
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Sep 2021.
- Individual participant dataSharing planned: Yes
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
An observational study of Scrub Typhus, run by University of Oxford.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 29 Sep 2021. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
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). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Sep 2021; AzTrials last refreshed its copy on 8 Nov 2026.