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Investigating Vector-Borne Determinants of Aedes Transmitted Arboviral Infections in Cambodia: An Observational Longitudinal Cohort Study in Children

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT03534245
Recruitment Status : Active, not recruiting
First Posted : May 23, 2018
Last Update Posted : July 17, 2019
Information provided by (Responsible Party):
National Institutes of Health Clinical Center (CC) ( National Institute of Allergy and Infectious Diseases (NIAID) )

Brief Summary:


Some mosquitos carry viruses that can cause disease. Some examples are dengue and Zika. The mosquitos spread disease by biting people and infecting them with the virus. Children, elderly people, and people who are already sick are especially likely to get infected. Researchers want to learn more to help make new medicines to treat these viral infections.


To learn more about how mosquitos infect people, and why young children are more likely to get sick than other people.


Healthy children 2-9 years old who live near the study site. This is Kampong Speu District Referral Hospital in Chbar Mon, Cambodia.


At visit 1, participants will have a physical exam. A small amount of blood will be taken from their arm or finger. Parents will answer questions about the participant s general health and medical history.

Participants will come back to the study site every wet season and every dry season for the next 3 years. The visits will be the same as visit 1 and take about 1 hour.

If at any time during the study the participant gets a fever and has other symptoms that could be caused by these viral diseases, they should be brought to the study site. These symptoms might include headache, pain behind the eyes, muscle pain, or joint pain. They can also include a rash that lasts longer than 12 hours.

Participation ends after the final study visit in late 2021.


Condition or disease
Dengue Fever

Detailed Description:
Mosquito-borne viruses continue to cause significant global morbidity and mortality, particularly in Southeast Asia. When mosquitoes deliver the virus into the skin of humans while probing for a blood meal, they deposit also saliva, which contains a myriad of pharmacologically active compounds that modulate the host immune system. Most vaccines against vector-borne diseases under development ignore the importance of the complex infectious inoculum delivered by the mosquito vector and the subsequent host immune response to mosquito salivary proteins. Many studies of vector-borne disease do not evaluate what role vector-derived factors play in the host immune response of these infections. A cumulative body of evidence from animal models and limited retrospective human data demonstrates that a variety of vector-derived components, including salivary components, are codelivered with the pathogen and may play an important role in the establishment and dissemination of arboviral infection. Knowledge of the effect of these vector-derived factors on the development of arboviruses in the human is limited. Here, we will establish and follow a longitudinal pediatric cohort study to describe the burden of dengue virus and to carefully examine the immune response to exposure of the salivary proteins of Aedes aegypti, the mosquito vector of dengue, Zika and chikungunya viruses. This study will serve as a foundation so that future studies may contribute to further understanding how saliva immunity impacts arboviral disease development i Cambodia, a country endemic to these viruses.

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Study Type : Observational
Actual Enrollment : 775 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Investigating Vector-Borne Determinants of Aedes-Transmitted Arboviral Infections in Cambodia: an Observational Longitudinal Cohort Study in Children
Actual Study Start Date : May 16, 2018
Estimated Primary Completion Date : September 30, 2021
Estimated Study Completion Date : September 30, 2021

Healthy children aged 2 - 9 years

Primary Outcome Measures :
  1. Prevalence of symptomatic and inapparent dengue infection (serotypes 1-4) as detected semiannually via ELISA assay (binary outcome present/absent) over a three-year period in Kampong Speu in children aged 2-9 years old [ Time Frame: Semi-Annual visits and sick/convalescent visits throughout study enrollment ]
    Detailed knowledge of dengue seroprevalence and transmission season variability will help establish an epidemiological foundation to prepare for larger future studies such as disease incidence studies or vector interventional trials.

  2. Prevalence of Aedes aegypti salivary gland homogenate reactivity as detected by ELISA assay (binary outcome present/absent) during wet and dry seasons over a three-year period in Kampong Speu in children aged 2-9 years old [ Time Frame: Semi-annual visits and sick/convalescent visits throughout study enrollment ]
    Characterizing the Ae. aegypti salivary protein reactivity profile in Cambodians is the first step prior to assessing how Ae. aegypti saliva exposure modulates disease in humans.

Secondary Outcome Measures :
  1. Western blot analysis of sera from participants with strongest ELISA positivity to Ae. aegypti whole salivary gland homogenate compared to Anopheles and Culex to assess cross-reactive immunogenicity to mosquito saliva versus specific Aedes marke... [ Time Frame: Semi-annual visits and sick/convalescent visits throughout study enrollment ]
  2. Positive RT-PCR result for diagnosis of dengue, chikungunya, and Zika viruses (or IgM capture ELISAs for dengue as needed) [ Time Frame: Semi-annual visits and sick/convalescent visits throughout study enrollment ]
  3. Geographic information system with all data components (mosquito catch sites, houses, schools) referenced by latitude and longitude in addition to a series of map layers (point maps, smoothed maps) to evaluate relationships between IgG intensity... [ Time Frame: Semi-annual visits and sick/convalescent visits throughout study enrollment ]
  4. Seroconversion to Ae. aegypti salivary homogenate in relationship to season (wet versus dry) and collected time-dependent variables defined as mean and maximum rainfall, te,perature and humidity [ Time Frame: Semi-annual visits and sick/convalescent visits throughout study enrollment ]
  5. Capture a minimum of 25 female Aedes aegypti mosquitoes for transcriptional comparison to LMVR-reared Aedes aegypti mosquitoes [ Time Frame: Duration of study enrollment ]

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   2 Years to 9 Years   (Child)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Community-based cohort of children from the town of Chbar Mon in Kampong Speu, Cambodia, who live within 5.5 km to the Kampong Speu District Referral Hospital.@@@

In order to be eligible to participate in this study, an individual must meet all of the following criteria:

  1. Provision of signed and dated informed consent form
  2. Stated willingness to comply with all study procedures and availability for the duration of the study
  3. Male or female, aged 2-9 years
  4. Live within approximately 5.5 km of study site
  5. In good general health as evidenced by medical history
  6. Willing to allow biological samples to be stored for future research.


  1. Current or prior use within last 6 months of any immunosuppression (e.g. intravenous immunoglobulin, steroids, interferon therapy)
  2. Treatment with another investigational drug, vaccine, or other intervention within six months of screening

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03534245

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Kampong Speu Referral Hospital
Chbar Mon, Kampong Speu, Cambodia
Sponsors and Collaborators
National Institute of Allergy and Infectious Diseases (NIAID)
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Principal Investigator: Jessica E Manning, M.D. National Institute of Allergy and Infectious Diseases (NIAID)

Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: National Institute of Allergy and Infectious Diseases (NIAID) Identifier: NCT03534245     History of Changes
Other Study ID Numbers: 999918100
First Posted: May 23, 2018    Key Record Dates
Last Update Posted: July 17, 2019
Last Verified: July 11, 2019

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by National Institutes of Health Clinical Center (CC) ( National Institute of Allergy and Infectious Diseases (NIAID) ):
Mosquito Salivary Protein
Dengue Fever
Kampong Speu
Additional relevant MeSH terms:
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Arbovirus Infections
Virus Diseases
Flavivirus Infections
Flaviviridae Infections
RNA Virus Infections
Hemorrhagic Fevers, Viral