Doun Kaev

Researchers are studying the immune responses to zoonotic virus exposure in healthy adults aged 18 to 65 years in Cambodia. The study focuses on individuals at high risk of exposure to animals or their excreta, such as those involved in guano farming, wet markets, or living near animal habitats like bat caves. The primary goal is to understand immunity to viruses including H5N1, Nipahvirus, and beta coronaviruses by examining people with varying levels of exposure risk. Participants will undergo whole blood collection, with 30 mL taken at the initial visit (Day 0) and up to two optional additional collections spaced at least 30 days apart. These samples will be used to analyze antibody binding and neutralizing activity against viral proteins, as well as to isolate viral antigen-specific B cells for detailed immune profiling. The study involves screening individuals based on exposure risk and may include those living or working within 5 kilometers of relevant animal habitats. During the study, researchers will collect plasma samples and perform immune analyses at multiple time points between Day 0 and up to 720 days later. Participants will be evaluated for antibody responses and B cell characteristics related to zoonotic viruses. The study includes careful monitoring of participants' health, with exclusion of those showing signs of acute infection or immune deficiencies. The total involvement period may extend over two years, with several visits and blood sample collections to assess long-term immune signatures.

Vector-borne diseases, caused by bites from infected insects like mosquitoes and ticks, result in nearly one million deaths per year and are increasing, especially in Southeast Asia. In Cambodia, these diseases may account for about 10% of fevers, but many cases go undiagnosed due to limited diagnostic resources. Researchers aim to better understand these illnesses and find new ways to detect and study them using advanced genetic testing methods. The study enrolls people aged 2 months to 65 years who have a fever of at least 38 degrees Celsius, those diagnosed with infections by specific concerning pathogens, and close contacts of those infected. Participants will provide medical history and demographic information, and children will be weighed to ensure safe blood sampling. Blood tests and nasal swabs (for those with respiratory symptoms) are collected to identify pathogens using metagenomic sequencing technologies. If a highly concerning pathogen is found, follow-up samples and testing of close contacts may occur. Participants will answer questionnaires about their health and travel history. They may be contacted for optional follow-up blood and nasal swab samples 1-2 weeks and/or up to 3 months after enrollment. The study monitors the presence of infectious agents to better describe the febrile disease landscape in Cambodia and assess the impact of vector-borne and emerging pathogens using advanced genomic tools.