A cluster investigation method for studying dengue virus genetic diversity, immunological responses and entomological dynamics
ISRCTN | ISRCTN21091116 |
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DOI | https://doi.org/10.1186/ISRCTN21091116 |
Secondary identifying numbers | ctu03dxfeb08 |
- Submission date
- 16/07/2008
- Registration date
- 17/07/2008
- Last edited
- 24/07/2013
- Recruitment status
- Stopped
- Overall study status
- Stopped
- Condition category
- Infections and Infestations
Plain English summary of protocol
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
Contact information
Scientific
The Oxford University Clinical Research Unit (OUCRU)
Hospital for Tropical Diseases
190 Ben Ham Tu
Ho Chi Minh City
Q5
Viet Nam
Phone | +84 8 924 1983 |
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khoat@oucru.org |
Study information
Study design | Prospective, observational cohort study |
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Primary study design | Observational |
Secondary study design | Cohort study |
Study setting(s) | Hospital |
Study type | Screening |
Participant information sheet | Not available in web format, please use the contact details below to request a patient information sheet |
Scientific title | A community-based study using household sampling around dengue index cases for assessing genetic diversity, immunological responses and entomological transmission dynamics |
Study objectives | 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(s) | 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 |
Health condition(s) or problem(s) studied | 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 |
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 study start date | 20/07/2008 |
Completion date | 01/10/2011 |
Reason abandoned (if study stopped) | Participant recruitment issue |
Eligibility
Participant type(s) | Patient |
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Age group | Not Specified |
Sex | Both |
Target number of participants | Patients 100, controls 100 |
Key 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 |
Key exclusion criteria | Does not meet inclusion criteria |
Date of first enrolment | 20/07/2008 |
Date of final enrolment | 01/10/2011 |
Locations
Countries of recruitment
- Viet Nam
Study participating centre
Q5
Viet Nam
Sponsor information
University/education
Clinical Trials and Research Governance
Manor House
John Radcliffe Hospital
Headington
Oxford
OX3 9DZ
England
United Kingdom
Website | http://www.ox.ac.uk/ |
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https://ror.org/052gg0110 |
Funders
Funder type
Charity
No information available
Results and Publications
Intention to publish date | |
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Individual participant data (IPD) Intention to share | No |
IPD sharing plan summary | Not provided at time of registration |
Publication and dissemination plan | Not provided at time of registration |
IPD sharing plan |