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The Clinical Epidemiology of Scrub Typhus in Humans, Chiggers and Rodents

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ClinicalTrials.gov Identifier: NCT02876367
Recruitment Status : Active, not recruiting
First Posted : August 23, 2016
Last Update Posted : November 9, 2018
Sponsor:
Collaborators:
Mahidol Oxford Tropical Medicine Research Unit
Laos Oxford Mahosot Hospital Wellcome Trust Research Unit
Wellcome Trust Centre for Human Genetics, Oxford
Centre National de la Recherche Scientifique, France
Information provided by (Responsible Party):
University of Oxford

Brief 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'.

Condition or disease
Scrub Typhus

  Show Detailed Description

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Study Type : Observational
Estimated Enrollment : 1200 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: The Clinical Epidemiology of Scrub Typhus in Humans, Chiggers and Rodents
Actual Study Start Date : September 1, 2016
Actual Primary Completion Date : April 10, 2018
Estimated Study Completion Date : December 31, 2018

Resource links provided by the National Library of Medicine


Group/Cohort
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.



Primary Outcome Measures :
  1. 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 ]
  2. 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 ]
  3. Identify key mite vectors and rodent hosts involved in scrub typhus natural history, human infection, and disease virulence [ Time Frame: up to 24 months ]

Secondary Outcome Measures :
  1. Determine changes in scrub typhus antibody titres over time and identify acutely infected scrub typhus cases [ Time Frame: up to 24 months ]
  2. Identify human-derived O. tsutsugamushi genotypes to define genomic relationships between human, rodent and mite-derived genotypes. [ Time Frame: up to 24 months ]
  3. Identify putative determinants of human infection/virulence [ Time Frame: up to 24 months ]
  4. 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 ]

Biospecimen Retention:   Samples Without DNA

Group 1: 10 ml of blood will be collected from the participant.

Group 2: 0.2 ml of blood will be collected from the participant.



Information from the National Library of Medicine

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Ages Eligible for Study:   10 Years and older   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
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

Criteria

Inclusion Criteria:

Acute scrub typhus (Group 1)

  1. Presenting with fever >38 C and testing positive by scrub typhus RDT.
  2. Male or Female, aged 10 years or above.
  3. Participant is willing and able to give informed consent for participation in the study.

Scrub typhus serosurvey (Group 2)

  1. Villagers living in an environment in which scrub typhus is known to be present, who are asymptomatic.
  2. Male or Female, aged 10 years or above.
  3. Participant is willing and able to give informed consent for participation in the study.

Exclusion Criteria:

Acute scrub typhus (Group 1)

  1. Villagers/patients under 10 years of age.
  2. Those unwilling to give written informed consent.

Scrub typhus serosurvey (Group 2)

  1. Villagers/patients under 10 years of age.
  2. Those unwilling to give written informed consent.

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Responsible Party: University of Oxford
ClinicalTrials.gov Identifier: NCT02876367     History of Changes
Other Study ID Numbers: OxTREC no. 48-15
First Posted: August 23, 2016    Key Record Dates
Last Update Posted: November 9, 2018
Last Verified: November 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Yes
Keywords provided by University of Oxford:
Epidemiology
Additional relevant MeSH terms:
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Typhus, Epidemic Louse-Borne
Scrub Typhus
Rickettsia Infections
Rickettsiaceae Infections
Gram-Negative Bacterial Infections
Bacterial Infections