Environment, Pathogens, and Host Interactions in Melioidosis

NCT ID: NCT07345910

Last Updated: 2026-01-16

Basic Information

• Recruitment Status: NOT_YET_RECRUITING
• Total Enrollment: 2400 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2026-06-01
• Study Completion Date: 2034-12-01

Brief Summary

This is a longitudinal, multicentre observational study conducted across three established microbiology units integrated within hospital and community health systems in Thailand, Lao PDR, and Cambodia.

The hospital cohort will enroll approximately1,000 patients with positive melioidosis. Participants will be followed at six time points from admission through one year (post-discharge) to capture acute and recovery-phase outcomes, with clinical data collected on demographics, comorbidities, exposures, treatment, adherence, and outcomes.

For each confirmed case, a healthy control will be recruited within two weeks and matched by age, sex, and village of residence. Controls with no symptoms or history of melioidosis will provide a single blood sample at enrolment and will be followed by telephone at 6 and 12 months.

In addition to hospital-based surveillance, a high-risk community in northern Ubon Ratchathani-referred to as the Sandbox Village-will be intensively monitored to capture subclinical infections and to assess environmental factors influencing disease acquisition.

This study is funded by the Wellcome Trust. The grant reference number is 323077/Z/24/Z

Detailed Description

This is a longitudinal, multicentre observational study conducted across three established microbiology units integrated within hospital and community health systems:

• Sunpasitthiprasong Hospital, Ubon Ratchathani, Thailand (MORU);
• Mahosot Hospital, Vientiane, Lao PDR (LOMWRU); and
• Angkor Hospital for Children, Siem Reap, Cambodia (COMRU).

In addition to hospital-based surveillance, a high-risk community in northern Ubon Ratchathani-referred to as the Sandbox Village-will be intensively monitored to capture subclinical infections and to assess environmental factors influencing disease acquisition.

Participant Recruitment and Follow-up

Hospital cohort:

Patients with melioidosis will be recruited at all three hospital sites. The study plans to recruit 1,000 patients, who will be followed longitudinally at six time points: Day 0 (admission), Days 3 and 7 (acute phase), and Days 30, 180, and 365 (recovery phase).

Clinical data collected will include demographic characteristics, underlying comorbidities, environmental exposures, lifestyle and behavioural factors, treatment history, patient-reported medication adherence, and follow-up outcomes.

Healthy controls:

Each patient will be matched with a healthy control recruited within two weeks of diagnosis, based on age, sex, and village of residence. Controls will have no current symptoms or prior history of melioidosis. They will provide a single blood sample at enrolment for DNA extraction and antibody profiling and will be followed up by telephone on Days 180 and 365.

Community cohort:

To complement hospital-based data and to identify subclinical infections, intensive community surveillance will be conducted in the Sandbox Village, a high-incidence area within the Ubon Ratchathani region. All residents (approximately 400 individuals) will be enrolled. DNA samples will be collected at baseline, and serum samples will be obtained every two months over a 42-month period, either at participants' homes or at a central village location, to measure antibody responses to Burkholderia pseudomallei as a proxy for exposure.

Community cohort:

To complement hospital-based data and to identify subclinical infections, intensive community surveillance will be conducted in the Sandbox Village, a high-incidence area within the Ubon Ratchathani region. All residents (approximately 400 individuals) will be enrolled. DNA samples will be collected at baseline, and serum samples will be obtained every two months over a 42-month period, either at participants' homes or at a central village location, to measure antibody responses to Burkholderia pseudomallei as a proxy for exposure.

Conditions

Melioidosis

Study Design

• Observational Model Type: COHORT
• Study Time Perspective: PROSPECTIVE

Study Groups

Melioidosis patients

Patients confirmed to have melioidosis

No interventions assigned to this group

Healthy controls

Healthy controls will be enrolled for each confirmed melioidosis case. A healthy control is defined as an individual with no current fever, no evidence of soft tissue infection, and no prior history of melioidosis. Controls will be recruited within approximately two weeks of case identification and will be matched to cases by age (±5 years), sex, and village of residence.

No interventions assigned to this group

Sandbox village cohort

All residents of the Sandbox Village, a high-risk area for melioidosis, will be enrolled to monitor disease progression and to evaluate the impact of improved water sanitation.

No interventions assigned to this group

Eligibility Criteria

Inclusion Criteria

• Age ≥20 years
• Positive for Burkholderia pseudomallei from any clinical samples
• Resident of the study area for at least two years, including the follow-up period
• Willing to participate and give informed consent.

• Age ≥20 years
• Currently healthy as judged by study doctor
• Resident of the study area for at least two years, including the follow-up period
• Willing to participate and give informed consent.

• Age ≥20 years
• Resident of the study area for at least two years, including the follow-up period
• Willing to participate and give informed consent.

Exclusion Criteria

• Current tuberculosis (TB) or TB treatment within the past six months
• Documented HIV infection or use of immunosuppressive therapy in the past 12 months

• History of melioidosis
• Significant acute illness
• Current fever or soft tissue infection

-N/A

• Minimum Eligible Age: 20 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Oxford

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Kamolchanok Claire Chewapreecha, PhD

Role: PRINCIPAL_INVESTIGATOR

Mahidol Oxford Tropical Research Unit

Locations

Cambodia-Oxford Medical Research Unit (COMRU)

Siem Reap, , Cambodia

Lao-Oxford-Mahosot Hospital Wellcome Trust Research Unit (LOMWRU)

Vientiane, , Laos

Sunpasitthiprosong Hospital

Ubon Ratchathani, , Thailand

Countries

Cambodia; Laos; Thailand

Central Contacts

Kamolchanok Claire Chewapreecha, PhD

Role: CONTACT

claire@tropmedres.ac

662 203 6333

Facility Contacts

Paul Turner, MD

Role: primary

Pault@tropmedres.ac

Elizabeth Ashley, MD

Role: primary

Elizabeth.Ashley@tropmedres.ac

Kamolchanok C Chewapreecha, PhD

Role: primary

claire@tropmedres.ac

022036333

Other Identifiers

MEL25001

Identifier Type: -

Identifier Source: org_study_id