Sylvatic Transmission and Reservoir Potential of Zika, Dengue, and Chikungunya Viruses of Co-located Humans and Long-tailed Macaques in Thailand and Cambodia

Study Overview
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Brief Summary
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Background: Zika, dengue, and chikungunya are spread by mosquitos. These diseases have a major impact on public health. This is especially true in in Southeast Asia. Non-human primates (such as macaques) could play an essential role in spreading these diseases. Researchers want to further understand the relationship between humans and these primates. They want to see how this affects how mosquito-borne viruses are spread in Southeast Asia. Objective: To describe the prevalence of Zika virus, dengue virus, and chikungunya virus in the blood of people who live close to long-tailed macaques in Thailand and Cambodia. Eligibility: Healthy people aged 18-55 who have lived or worked within approximately 10 kilometers of the Wat Amphae Phnom monkey habitat in Kampong Speu, Cambodia, for a minimum of 2 years Design: Participation will last 1 day. Participants will be screened in person through an interview. Their medical history will be reviewed. Participants will give information about themselves. This will include sex, age, and behaviors related to the spread of mosquito-borne disease. For example, they will be asked about the number of water containers at their home. They will be asked about recent travel. They will be asked about the extent of their contact with the macaques. Participants will give a blood sample....

Detailed Description
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Arboviral epidemics continue to emerge suddenly and spread of disease is unpredictable. The 2015-16 Zika epidemic resulted in a high case number in Thailand, but not in neighboring Cambodia. It is known that nonhuman primates (NHPs) are important reservoirs of arboviruses, but the importance of their epidemiological role in the transmission of arboviruses is not clearly understood. While transmission dynamics are complex and require consideration of many variables, primate reservoirs are not routinely sampled, particularly in Southeast Asia, because of the level of operational complexity and skill required. Here, we propose a serological survey for evidence of Zika virus (ZIKV), dengue virus (DENV), and chikungunya virus (CHIKV) exposure in long-tailed macaques and human adults who live or work in close proximity to these monkeys in Thailand and Cambodia. We hypothesize that ZIKV seroprevalence in both humans and macaques will be higher in Thailand than Cambodia. With the current rise of arboviral diseases around the world, we hope the results of this study contribute to better understanding of the epidemiology and burden of arboviral diseases in this region.

Official Title
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Investigating the Sylvatic Transmission and Reservoir Potential of Zika, Dengue, and Chikungunya Viruses of Co-located Humans and Long-tailed Macaques of Thailand and Cambodia

Conditions
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Dengue Fever, Zika, Vector-Borne Diseases, Chikungunya

Participation Criteria
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Eligibility Criteria
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INCLUSION CRITERIA: In order to be eligible to participate in this study, an individual must meet all of the following criteria: Provision of signed and dated ICF Able to provide informed consent Stated willingness to comply with study procedures Male or female, aged 18-55 years Live/work within approximately 10 km of the Wat Amphae Phnom monkey habitat for minimum of 2 years In good general health as evidenced by screening medical history Willing to allow biological samples to be stored for future research EXCLUSION CRITERIA: 1. Any underlying, chronic, or current medical condition that, in the opinion of the investigator, would interfere with participation in the study (e.g., inability or great difficulty in drawing blood)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| 1<br>Adults ages 18-55 with ZIKV, DENV, and/or CHIKV seroprevalence. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assessment of seroprevalence via screening ELISA and/or PRNTSO titers for ZIKV, DENV, and CHIKV in Cambodian adults. | PRNT assays are the gold standard to detect virus-specific antibodies given multiple circulating flaviviruses in Southeast Asia. Understanding the prevalence of these Aedes transmitted viruses, and how they differ across the Mekong region, is critical to understanding the risk to Cambodians of future epidemics. | Day 0 | 
| Assessment of seroprevalence via screening ELISA and/or PRNTSO titers for ZIKV, DENV, and CHIKV in Cambodian macaques as compared to humans. | Because primates can be amplifying hosts of these viruses, it is critical to understand the prevalence of these Aedes-transmitted viruses in macaques as well. | Day 0 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparative assessment of seroprevalence via PRNTSO titers for ZIKV, DENV, and CHIKV in Cambodian adults and macaques to that of Thai adults and macaques. | Understanding how the prevalence of these Aedes transmitted viruses differs across the Mekong region is critical for cross-border disease detection and management, particularly given the high level of human migration in the Greater Mekong Subregion. | Day 0 | 
| Assessment of reactivity to salivary gland homogenate of Aedes aegypti as detected by ELISA or western blot in human and macaque sera. | Characterizing vector salivary protein reactivity profiles (mosquitos, ticks, fleas) in Cambodians with vector- borne disease is the first step to better understanding transmission patterns, responsible vectors, and Cambodians' risk of exposure to these vectors. | Day 0 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Arbovirus, Serological Survey, Vector-Borne Diseases, Seroprevalence, Southeast Asia, Natural History