PREDICT - WILDLIFE DISEASE SURVEILLANCE IN VIET NAM

The rate of infectious diseases emergence, especially zoonotic pathogens that are transmitted between humans and animals, is rising. Human activities such as handling of bush-meat and wildlife trade, as well as land use change and human encroachment into wildlife habitat, are pushing humans and animals in closer contact and making opportunities for disease spillover from wildlife to human populations. Of 1,415 human pathogens listed, approximately 60% are known to be zoonotic and multiple pathogens are related to a human emerging infectious disease (Taylor et al., 2001). The origin of HIV virus has been shown to be associated with hunting and consumption of non-human primates (Gao et al., 1999)and studies of transmission of Ebola virus to human populations indicate an association with  contact between infected great apes and humans via hunting and consuming primates (Leroy et al., 2004).  The SARS pandemic was associated with the wild carnivore trade and demonstrated a link to the farming and trading of civets in markets in Southern China (Tu et al., 2004).Identifying pathogens of pandemic potential in wildlife and understanding and mitigating the risks of spillover into humans or domestic animals is critically important to the global effort to reduce the emergence of pandemic threats.

The PREDICT project was designed to build a global early warning system of zoonotic disease at wildlife/livestock/human interfaces. The project is one of multiple components of the Emerging Pandemic Threats Program funded by the United States Agency for International Development (USAID). In Viet Nam the extensive study identified potential high-risk interfaces for zoonotic disease spillover from wildlife to humans performed by Wildlife Conservation Society in partnership with Department of Animal Health (DAH), Ministry of Agriculture and Rural Development; Vietnam National University of Agriculture (VNUA); provincial wildlife management and animal health departments; national rescue centers and NGOs. The project also established the local capacity to conduct disease surveillance and pathogen detection in wildlife at high-risk interfaces for disease transmission, many of which are linked to domestic and international trade of wildlife.

WILDLIFE DISEASE SURVEILLANCE

Through the collaborative effort with Vietnamese research, academic and government institutions, PREDICT performed 90 sampling events across Viet Nam, collected nearly 7,000 samples from over 2,054 individual wild animals. The sample collection targets at high-risk disease transmission interfaces where live animals are sold, restaurants serving bush-meat, wildlife farms, wildlife rescue centers and sanctuaries, and wildlife in/around human dwelling.

Figure 1: Collecting samples from fruit bats in Soc Trang Province (Photo: Boripat Siriaroonrat)

Over 16,300 family conventional PCR assays were implemented in national and international laboratories to screen for unknown and known viruses from 10 virus families (Arenaviruses, Flaviviruses, Paramyxoviruses, Hantaviruses, Bunyaviruses, Coronaviruses, Henipaviruses, Filoviruses, Herpesviruses and Rhabdoviruses). The positive suspect samples were confirmed by cloning and sequencing to identify the viruses.   In Viet Nam, during 5 years of the project, 24 novel viruses (2 Corona, 2 Herpes, 5 Paramyxo and 15 Rhabdoviruses) and 3 known viruses (1 Corona, 1 Paramyxo and 1 Influenza) were detected.  Further work will be focused on understanding the biological and behavioral factors influencing the spillover, amplification and spread of pathogens at these high-risk interfaces to mitigate the risk of pandemic disease emergence.

CAPACITY BUILDING FOR WILDLIFE PATHOGEN DETECTION

PREDICT project provided methods of wildlife identification, safe handling, and sample collection to provincial-level and district-level animal health officers and wildlife management officers through their participation in sampling events in the field. Participants joined the sampling trip as members of the sampling team for practical training and the participants were trained in the relevant theory before practicing collecting samples with wildlife experts of Wildlife Conservation Society. New sampling techniques from around the world were applied and optimized to collect samples in Viet Nam, such as non-invasive techniques for the collection of saliva samples from non-human primates.  These techniques were also provided to staff of Department of Animal Health and Forest Protect Department during the wildlife farm sampling trips in Dong Nai Province.

Figure 2: Practicing DNA electrophoresis methods during the PREDICT Molecular Diagnostics Training at the Vietnam National University of Agriculture (Photo: WCS Viet Nam)

PREDICT also provided molecular diagnostic protocols for wildlife samples to laboratory technicians with training provided by PREDICT laboratory experts from the University of California, Davis, and Wildlife Conservation Society. The participats were provided protocols of conventional PCR assays to screen for a range of viral families and taught laboratory biosafety through hands-on trainings organized at the Vietnam National University of Agriculture laboratory. The use of appropriate sample storage equipment, laboratory equipment and the PREDICT positive control was also covered in laboratory trainings.

During the 5 years of the project, a total of 561 participants from different agencies from the fields of wildlife conservation, animal health, human health, wildlife management, law enforcement and research/academic institutions were involved in PREDICT trainings. These participants were not only taught methods of sample collection and sample diagnosis, but also introduced to the One Health approach to understanding and preventing the emergence of disease of pandemic potential. The approach was combined into PREDICT and WCS Viet Nam trainings in collaboration with partner agencies and institutions.

Figure 3: Wildlife Health Trainingfor wildlife management officers and animal health officers in Dong Nai Province

REFERENCE

GAO, F., BAILES, E., ROBERTSON, D. L., CHEN, Y., RODENBURG, C. M., MICHAEL, S. F., CUMMINS, L. B., ARTHUR, L. O., PEETERS, M. & SHAW, G. M. 1999. Origin of HIV-1 in the chimpanzee Pan troglodytes troglodytes. Nature, 397, 436-441.

LEROY, E. M., ROUQUET, P., FORMENTY, P., SOUQUIERE, S., KILBOURNE, A., FROMENT, J.-M., BERMEJO, M., SMIT, S., KARESH, W. & SWANEPOEL, R. 2004. Multiple Ebola virus transmission events and rapid decline of central African wildlife. Science, 303, 387-390.

TAYLOR, L. H., LATHAM, S. M. & MARK, E. 2001. Risk factors for human disease emergence. Philosophical Transactions of the Royal Society of London B: Biological Sciences, 356, 983-989.

TU, C., CRAMERI, G., KONG, X., CHEN, J., SUN, Y., YU, M., XIANG, H., XIA, X., LIU, S. & REN, T. 2004. Antibodies to SARS coronavirus in civets. Emerging infectious diseases, 10, 2244.