Plain English Summary
Background and study aims
Dengue is an infectious disease caused by four types of dengue virus, transmitted by mosquitoes. Dengue can be present with no symptoms at all or as a mild illness with fever, headache and joint aches, but can also be complicated by bleeding and shock. There is no treatment for dengue beyond supportive care and there is no vaccine. The World Health Organization lists dengue fever as one of the most important emerging infectious diseases in the world.
Dengue viruses are highly variable: their genetic material changes slightly each time they replicate within their human or mosquito host. As a result, the millions of individual viruses within a host are all slightly different from each other. We call this the diversity of the virus. The goal of this study is to obtain dengue viruses from patients in hospital with dengue, from the mosquitoes in and around their house and from household members and neighbours that may be infected with or without being sick, and to test if the degree of diversity of the virus in different hosts is related to the severity of illness. The study will also look at the patients immune response in different degrees of dengue severity.
Who can participate?
This study aims to recruit dengue patients of all ages who have a high fever and test positive for dengue virus. This study will recruit between 18-110 dengue patients per year in Binh Thuan province. The actual number will depend on how many cases occur in the province.
What does the study involve?
When a dengue case is reported, study staff will take blood samples from the patient. They will take blood when the patient first arrives, and once per day until his/her fever is gone. These samples will be used for testing of the type of dengue virus, the number of viruses and their diversity, and of the patients immune response. Study staff will also draw blood from household members and neighbours of the patient. This study estimates there will be about 5-10 people who live close to the patient. Mosquito traps will be placed around houses with a dengue patient. A large black plastic container will also be used to collect mosquito larvae, pupae and eggs. These larvae will be bred and stored for future analysis.
What are the possible benefits and risks of participating?
Family members and neighbours will be tested for dengue by the study staff and referred to the community health station for clinical assessment and follow-up. Taking blood samples may cause mild discomfort and bruising.
Where is the study run from?
The study is run by researchers at the Oxford University Clinical Research Unit (OUCRU) Viet Nam; Binh Thuan Medical College Binh Thuan Province, Viet Nam; and the Academic Medical Center Amsterdam, the Netherlands.
When is the study starting and how long is it expected to run for?
The study will run from July 2008 to October 2011 for a total of 3 years and 2 months. After enrolment of 16 index patients and 39 household contacts/neighbours, the study was stopped due to slow enrolment and problems with study staffing.
Who is funding the study?
The Wellcome Trust (UK).
Who is the main contact?
The Clinical Trials Unit at the Oxford University Clinical Research Unit Viet Nam. +84839241983
Trial website
Contact information
Type
Scientific
Primary contact
Dr Khoa Thai
ORCID ID
Contact details
The Oxford University Clinical Research Unit (OUCRU)
Hospital for Tropical Diseases
190 Ben Ham Tu
Ho Chi Minh City
Q5
Viet Nam
+84 8 924 1983
khoat@oucru.org
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
ctu03dxfeb08
Study information
Scientific title
A community-based study using household sampling around dengue index cases for assessing genetic diversity, immunological responses and entomological transmission dynamics
Acronym
Study hypothesis
1. Dengue virus exists as quasi-species in vivo and genetic diversity in mosquitoes is less
2. The genetic diversity of dengue virus in an infected index case is larger than the genetic diversity of the virus in asymptomatic subjects
3. The genetic diversity of dengue virus is less or qualitatively different in asymptomatic subjects, infected household member and cases of different severity
4. The antibody responses, viral load and antigenemia are lower in asymptomatic subjects
Ethics approval
Ethics approval received from:
1. Oxford Tropical Medicine Research Ethics Committee (OXTREC) (UK) on the 24th April 2008 (ref: 10/08)
2. Binh Thuan Ethics Committee on the 26th May 2005
Study design
Prospective, observational cohort study
Primary study design
Observational
Secondary study design
Cohort study
Trial setting
Hospitals
Trial type
Screening
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
Condition
Dengue fever
Intervention
Patient data and clinical examination will be documented in case record forms (CRF). Blood samples will be collected according to the following schedule:
1. At presentation:
1.1. Blood sample for haematology, biochemistry, serology, NS1 and virology
1.1.1. 2 ml if less than 10 years of age
1.1.2. 5 ml if greater than or equal to 10 years of age
2. Daily follow up until afebrile: 2 - 5 ml blood sample for haematology, biochemistry, serology, NS1 and virology
Updated 24/07/2013: After enrolment of 16 index patients and 39 household contacts/neighbours, the study was stopped due to slow enrolment and problems with study staffing.
Intervention type
Other
Phase
Not Specified
Drug names
Primary outcome measure
To study dengue pathogenesis by comparing the genetic diversity of virus populations in dengue cases versus infecting mosquitoes and in asymptomatic subjects versus symptomatic cases of different severity
Secondary outcome measures
To study dengue pathogenesis by:
1. Studying the evolution of dengue virus quasispecies during the course of illness
2. Studying antibody responses, viral load and antigenemia in asymptomatic and symptomatic dengue virus infections of varying severity
Overall trial start date
20/07/2008
Overall trial end date
01/10/2011
Reason abandoned (if study stopped)
Participant recruitment issue
Eligibility
Participant inclusion criteria
Index cases:
1. All ages, either sex
2. Clinical suspicion of dengue:
2.1. Confirmed fever (i.e. an axillary temperature greater than 38°C at presentation)
2.2. Fever less than 72 hours duration
3. Positive NS1 antigen rapid test (indicative of viraemia)
Sample collection around index case:
All family members and neighbours
Participant type
Patient
Age group
Not Specified
Gender
Both
Target number of participants
Patients 100, controls 100
Participant exclusion criteria
Does not meet inclusion criteria
Recruitment start date
20/07/2008
Recruitment end date
01/10/2011
Locations
Countries of recruitment
Viet Nam
Trial participating centre
The Oxford University Clinical Research Unit (OUCRU)
Ho Chi Minh City
Q5
Viet Nam
Sponsor information
Organisation
University of Oxford (UK)
Sponsor details
Clinical Trials and Research Governance
Manor House
John Radcliffe Hospital
Headington
Oxford
OX3 9DZ
United Kingdom
Sponsor type
University/education
Website
Funders
Funder type
Charity
Funder name
The Wellcome Trust (UK) (grant ref: 077078)
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Basic results (scientific)
Publication list