Investigating Vector-Borne Determinants of Aedes Transmitted Arboviral Infections in Cambodia: An Observational Longitudinal Cohort Study in Children
Condition: Dengue Fever
MeSH terms: Dengue
Study type: Observational

Summary: 
      Background:

      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.

      Objective:

      To learn more about how mosquitos infect people, and why young children are more likely to
      get sick than other people.

      Eligibility:

      Healthy children 2-9 years old who live near the study site. This is Kampong Speu District
      Referral Hospital in Chbar Mon, Cambodia.

      Design:

      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.
    

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.
    

Observational model: Cohort
Time perspective: Prospective
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.@@@
      
Keywords: Mosquito Salivary Protein; Dengue Fever; Zika; Chikungunya; Kampong Speu; Natural History