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

NCT02876367 | Completed

• 1 other identifier: OxTREC no. 48-15
• Study Type: observational
• Target: 1,200
• Locations: 0 countries
• Sites: N/A

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'.

Conditions

Scrub Typhus

Keywords

Epidemiology

Outcome Measures

Primary Outcomes (3)

• determine the diversity of O. tsutsugamushi genotypes infecting rodents and mites and link these to their geographical distribution and associated habitat characteristics.

  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.

  up to 24 months

• Identify key mite vectors and rodent hosts involved in scrub typhus natural history, human infection, and disease virulence

  up to 24 months

Secondary Outcomes (4)

• Determine changes in scrub typhus antibody titres over time and identify acutely infected scrub typhus cases

  up to 24 months

• Identify human-derived O. tsutsugamushi genotypes to define genomic relationships between human, rodent and mite-derived genotypes.

  up to 24 months

• Identify putative determinants of human infection/virulence

  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.

  up to 24 months

Study Arms (2)

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.

Eligibility Criteria

• Age: 10 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)
• 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

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• University of Oxford: lead
• Mahidol Oxford Tropical Medicine Research Unit: collaborator
• Lao-Oxford-Mahosot Hospital Wellcome Trust Research Unit: collaborator
• Wellcome Trust: collaborator
• Centre National de la Recherche Scientifique, France: collaborator

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.

MeSH Terms

Conditions

Scrub Typhus

Condition Hierarchy (Ancestors)

Rickettsiaceae Infections; Gram-Negative Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses; Infections; Vector Borne Diseases

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 18, 2016
• First Posted: August 23, 2016
• Study Start: September 1, 2016
• Primary Completion: April 10, 2018
• Study Completion: December 31, 2018
• Last Updated: September 29, 2021

Record last verified: 2021-09

Data Sharing

• IPD Sharing: Will share