A Wildlife Mortality Monitoring Network that Promotes Human and Wildlife Health
Abstract
Known for its considerable human mortality rate, Ebola Virus Disease (EVD) requires swift outbreak detection. It is similarly deadly for great apes. During an outbreak of Ebola in the Republic of Congo in 2005, the human mortality rate was over 80% and an estimated 5000 great apes died. In partnership with the government, the Wildlife Conservation Society (WCS) worked with hunters, forest communities, and rangers to set up an early warning system for EVD by monitoring wildlife health. The system monitors and samples wildlife carcasses through a network of thousands of hunters covering more than 30,000 sq. km in northern Congo, where 60% of the world’s gorillas live, and promotes best practices in risk reduction for communities reliant on bushmeat for protein. Setting up the system involved three stages – establishing a wildlife mortality reporting network by building trust with communities, encouraging hunters to report observations and engaging necessary stakeholders; building capacity for rapid and safe carcass sampling in response to reports; and developing rapid diagnostics and reporting of results back to communities in conjunction with reinforcing awareness of health risks of eating carcasses. Staff were trained across the remote region in safe sampling techniques, and capacity developed for ebolavirus testing in-country, reducing time-to-results from weeks to minutes thanks to carcass-side testing with a Biomeme portable unit. This network monitors and protects the health of both wildlife and humans, particularly vital in a region with limited resources and accessibility to healthcare and where communities are reliant on bushmeat for protein.
Information
© The Authors 2023
What is the Incremental Value that Makes this a One Health Case?
Linking people’s own health and well-being – through awareness campaigns and by feeding back promptly on carcass testing results – to the wildlife health monitoring network encourages people to continue to participate in reporting carcasses. The programme helps to provide an early warning of potential outbreaks of Ebolavirus (EBOV) in wildlife, offering the opportunity to try to stem further spread, including time to enact measures to prevent spillover from wildlife to humans. So, this single network monitors and protects the health of both wildlife and humans, particularly vital in a region with limited resources and accessibility for healthcare and with communities reliant on bushmeat for protein. In addition, the community awareness campaigns regarding the health risks of interacting with carcasses that have died of unknown causes, and ways to reduce potential pathogen exposure during bushmeat butchering, handling and cooking, make spillover of Ebola – and other zoonoses -into humans less likely.
Learning Outcomes
1.
Recognise that engaging local hunters in a wildlife mortality monitoring network can improve human and wildlife health, boost awareness of health risks of handling carcasses that have died of unknown causes, and reduce overall zoonotic risks for subsistence communities.
2.
Understand that building trust in the community over the long term is crucial.
3.
Recognise that prompt reporting of results back to communities encourages continued participation in the wildlife mortality monitoring network.
Background and Context
Ebola virus disease in central Africa
Ebolavirus (Zaire ebolavirus or EBOV) was first identified in 1976 in the Democratic Republic of Congo. Epidemics have recurred in central and western Africa since, and have increased in frequency in recent decades, resulting in high mortality of humans and wildlife. The natural reservoir of EBOV remains undetermined, but fruit bats are suspected, and the virus is primarily transmitted between humans and from animals to humans through bodily fluids. In 1999, the Wildlife Conservation Society (WCS) created the Great Ape Health Program to improve our understanding of health threats to these endangered species. The programme now includes great ape and other wildlife disease investigations, great ape health visual monitoring, a hunter-based wildlife mortality surveillance programme, applied research into the ecology of EBOV and its effect on ape populations, and a community outreach/ education programme that informs our conservation research while also serving as an “early-warning system” to protect human health. This programme enhances understanding of the ecology of EBOV, including its likely reservoirs (Olson et al., 2019); routes of transmission between species; its effects on great ape populations; and examines possible approaches to mitigation of this threat to great apes, other wildlife, and people.
During an outbreak of EBOV in the Republic of Congo in 2005, the human mortality rate was over 80% (Nkoghe et al., 2005). In the 40 km radius of the Republic of Congo’s Lossi Reserve, an estimated 5000 great apes also died (Cameron et al., 2016); in some areas, the mortality of local gorilla populations was more than 90% (Bermejo et al., 2006). Following this outbreak, between 2005 and 2008, 10% of great ape faecal samples collected in the Odzala-Koukoua area had anti-EBOV antibodies (Reed et al., 2014).
Human and wildlife health in the Republic of the Congo
The last four outbreaks of Ebola Virus Disease (EVD) in humans in the Republic of the Congo – in 2001, 2002, 2003 and 2005 – are considered to have links to wildlife, as affected hunters had recently eaten infected bushmeat. Subsistence hunting is critical for food security in this region but is increasingly threatened by commercial wildlife trade to urban and peri-urban communities which has put pressure on wildlife populations and increased scarcity of wildlife. Thus, an opportunistically discovered wildlife carcass can seem like a great opportunity for food. Highlighting the risks of touching, butchering or eating a potentially infected carcass that died of unknown causes can reduce the risk of EBOV (and other zoonotic pathogen) spillover for local communities. Concurrently working with these hunting communities to monitor wildlife health and record carcass observations can provide an early warning of incipient wildlife disease outbreaks and help prevent spillover.
With limited funding for wildlife surveillance and veterinary medicine in the Republic of the Congo (RoC), and limited access for subsistence communities to adequate health care, increasing awareness of the relevance of wildlife health to human and livestock health at local, provincial, and central levels is essential. Introducing preventative approaches and building local capacity for surveillance is key to reducing human health risks from contact with wildlife e.g. from EBOV. Parallel to targeted EBOV surveillance, a wildlife carcass reporting network can offer access to information on other causes of wildlife mortalities.
Bringing diagnostic capacity from other nations into the country itself and ultimately to the carcass side enables better local engagement and rapid response and mitigation efforts in the case of detection of a pathogen of concern. With further investment into the diagnostic processes, next-generation sequencing analysis for the detection of bacterial and viral pathogens in the carcass samples could provide more answers. The mortality reporting network could be used to answer questions of veterinary health and conservation interest as well as pathogen discovery for yet unknown pathogens of One Health interest (Kuisma et al., 2019).
Transdisciplinary Process
In these subsistence communities, traditional superstitions and beliefs may contrast significantly with modern scientific knowledge and medicine. WCS has been working in the Republic of Congo for more than 30 years, spearheading conservation action to protect great apes and other wildlife and their habitat and working with many of these communities. The project has engaged close to 10,000 hunters and other community members from over 360 villages (Fig. 1) through community meetings and awareness campaigns (Figs. 2 and 3) to learn about the potential health risks associated with contact with dead animals where the cause of death is unknown, and how to report the locations of wildlife carcasses.
Each outreach campaign to villages lasts several days and visits several villages in the target region. The outreach team consists of a Congolese veterinarian, trained local professionals, and community members to ensure the visits and materials are culturally appropriate and build good relationships with communities and an atmosphere of trust. On arrival at a community, the team approaches the village chief for permission, and then offers their information verbally to all community members who are interested and available, including children. Messages include dispelling the belief that EVD is a result of sorcery, an overview of EVD ecology and history, the risks of close contact with or consuming meat from carcasses, what to do when you have found a carcass, including how to report it using an optional form, and how to avoid potential exposure to EBOV. The team uses a simple core message – do not touch, move or bury the carcass and contact the surveillance network immediately – and leaves information posters (Fig. 4) in communal buildings containing this message in French and the local language Lingala. Villagers receive the opportunity to share their experiences and ask questions, and the resulting discussions help to reinforce the educational message. The team also uses a local radio campaign to reach a wider audience and keep villagers they have already spoken with engaged.
Forty staff members from different sites across the northern RoC have also received the training in a biosafe sampling protocol for carcasses and became the carcass responder team. Staff members are trained in a two-person protocol that minimizes exposure to wildlife carcasses during the sampling process. The protocol involves personal protective equipment, disinfection, swab sampling and a de-activating buffer to minimize exposure risk to samplers and those handling the sample later, and a buddy system so participants can oversee each other’s tasks. Copies of the protocol are available in both English and French. Staff receive training in the history, ecology and dynamics of EBOV and the epidemiology and control of EVD outbreaks in humans as well as practical training in the sampling protocol and repeated practice in example scenarios. Refresher training is also organized where samplers with less experience accompany those with more experience. Carcass sampling kits are located at project bases in Brazzaville, Ouesso and Bomassa and research camps in the Nouabalé-Ndoki National Park (NNNP) (Mondika, Goualougo and Mbeli). As well as equipment, each kit includes a complete instruction guide to sampling and transport of the sample to the laboratory in Brazzaville.
With the addition of carcass-side testing (Fig. 5), the research assistants are now trained in the use of the Biomeme Polymerase Chain Reaction (PCR) thermocycler. Powered using iPhones, the Biomeme is a portable device that can be carried with the researcher to the site of the carcass. The device performs a PCR reaction to detect viruses, such as EBOV, within an hour on-site. Not only does this reduce the analysis time for carcass samples, from many days down to a single hour, it also means that if EBOV is detected, immediate emergency public health actions can be triggered. When results are negative, additional samples can then be taken to further explore the cause of death. The first tests on the Biomeme units were conducted in the field in June 2019, and they are now being integrated across the wildlife mortality reporting network with both English and French versions of the protocol. All samples are sent to the National Public Health Laboratory for confirmation of results.
When community members detect a carcass, they typically contact the carcass responder team by calling a dedicated carcass reporting hotline number that is linked to a central office. Sampling teams generally involve at least five people – two local porters or trackers, a person who knows the exact location of the carcass and two trained samplers. When the carcass responder team visits a village to sample a carcass reported by a village member, they reinforce the educational message by reminding villagers of the potential risks associated with the carcass and strengthen relationships with the community, including by offering to reimburse the phone call and to compensate for the effort involved in helping the sampling mission. Once test results are confirmed by the laboratory, the village receives a repeat visit or a telephone call to share the result and reinforce the outreach message further: when project staff reports back on the carcass testing results to communities, the messages about the risks of contact with carcasses are reiterated.
The project has helped bridge capacity at the Brazzaville National Public Health Laboratory to test for EBOV and other pathogens within the RoC. Together with the RoC National Public Health Laboratory, Congolese Foundation for Medical Research, the US National Institutes of Health, and the German Bernhard Nocht Institute for Tropical Medicine, WCS is promoting long-term capacity for robust in-country analysis of zoonotic diseases and wildlife mortality and morbidity events. The effort is the first of its kind in the country, building foundations for diagnostics of disease outbreaks and health monitoring to support wildlife study sites in the RoC. In order for the network to function effectively, the project built on existing long-term partnerships and relationships with communities and government partners. It required over 15 years to build an efficient, sustainable multi-sectoral network with key stakeholders from local to district to the provincial and central levels. Good coordination across multiple sectors from local to national levels is essential, as is the financial and human capacity to respond effectively and in a timely manner to mortality reports. The availability of communication tools such as cell phones for the village community members was a vital component.
Project impact
Hunters from over 360 villages have engaged in the programme over the past 10 years. Subsequently, nearly 10,000 hunters, and thousands more women and children, are now aware of the potential health risks associated with close contact with dead animals where the cause of death is not known. They also have information on how to minimize risks from handling, butchering and consuming bushmeat. Over 80 carcasses have been reported and analysed for EBOV at the national laboratory in Brazzaville, and over 40 people in northern Congo have been trained on the safe sampling protocol. All carcasses to date have tested negative for EBOV. Efficient sample analysis is an essential step to effective zoonoses monitoring and response – delays can enable a disease to spread and can reduce trust and incentive for future participation by communities. Through the efforts of multiple partners, the project has reduced the time for analysis from several weeks, including transport to a different country, to 2 days once the sample arrives at the laboratory in Brazzaville, to an hour if utilizing the carcass-side Biomeme platform (Figueroa et al., 2021).
Return visits to communities and conversations with village leaders indicate that risky contacts with wildlife carcasses are being avoided and reduced. Preventative approaches are particularly important in such isolated rural communities dependent on subsistence hunting and bushmeat for protein and with limited access to healthcare.
Although Central Africa remains as a high-risk region for EBOV emergence, the Republic of the Congo, home to the largest population of gorillas, has not experienced an EVD epidemic since 2005.
Project outlook
The project’s continuing expansion of carcass-side testing to reduce sample analysis time allows safety measures against EVD to be implemented even sooner should a positive result occur and encourages continued engagement of communities in the network. The Biomeme platform could potentially be rolled out in other countries across the region, and this, or similar, platforms could be adapted to identify other zoonotic pathogens of concern in the field. Detecting other bacterial and viral pathogens in carcasses in the wild could assist veterinary workers to help conserve great apes and help to prevent spillover and outbreaks of pathogens in humans.
WCS-Congo activities have a strong capacity-building momentum. However, continued funding is needed to train and support Congolese staff in the use of these techniques and technologies, with the aim of securing capacity in the Republic of Congo that will persist beyond the lifetime of this programme. The Wildlife Health Program (WHP) team greatly benefits from efforts from our Public Health partners to develop collaborative laboratory spaces in Brazzaville and Ouesso. These spaces require additional funding for human resources, diagnostic equipment and student training to help secure sustainable operations. A collaborative cross-sectoral effort is needed to meet the needs of zoonotic disease surveillance in ROC.
The next steps for the community surveillance network are efforts to explore outreach and impact beyond oral community meetings supplemented with posters. To diversify and improve the messaging impact, WCS will be introducing innovative, culturally relevant songs, theatre, and dance engagement to the community-based Ebola education outreach as well as expanding from an Ebola focus to include additional One Health messages. In addition, WCS is designing a survey tool for community outreach activities, to better understand how it is influencing knowledge, attitudes and behaviours within the local communities.
Despite relatively low human population densities in the various landscapes of northern Congo, these remote and previously inaccessible areas are experiencing a rapid increase in human population and competition for resources, leading to an increase in the number of interactions between wildlife and communities and, consequently, an increased risk of spillover events. The integrity of key areas for the preservation of biodiversity is under increasing threat from human activity, including elephant poaching for ivory, unsustainable levels of bushmeat hunting and infrastructure development, such as the construction of roads through the forests of Central Africa.
This situation demonstrates the need to increase conservation and One Health activities and interventions in the north of the country. To do this, WCS and other non-governmental, civil-society and/ or governmental organizations need to increase outreach capacity to engage more people on a regular basis, train more field agents capable of taking samples, and increase the diagnostic capacity in the country (e.g. provisioning of sampling and analysis material and equipment). These steps, when taken with the government and various collaborators, can strengthen the communities’ early warning system in order to detect and prevent EBOV emergence. To do so, the continued prioritization of pandemic and epidemic prevention at source and wildlife surveillance efforts by diverse external donors will be needed for the foreseeable future.
Conclusions
Participation of local hunters in a wildlife health monitoring network can be an effective means of enhancing the health of remote communities (and potentially, of wildlife). A centralized team that responds to reports and communicates findings to communities as soon as possible and in a culturally sensitive manner is vital for the long-term success of such wildlife mortality monitoring networks. Improved sample analysis times are an essential step to effective zoonoses monitoring and response. Rapid reporting of results to the community promotes human health through early implementation of mitigation measures and continued engagement with the community on risk reduction interventions for handling, butchering and consuming bushmeat. These, in turn, encourage continued commitment of hunters to the wildlife health monitoring programme. Work of this kind benefits from long-term investment and capacity building to set up a relationship of trust with the community and create sampling and testing networks that function effectively.
Group Discussion Questions
1.
Why do you think the team decided to set up the wildlife health monitoring network in this way? What were the likely challenges?
2.
How did the team build trust with the local community? What are the benefits and challenges of doing this?
3.
Why is it important to feedback results to communities and how did this help in this particular instance? What are the potential pitfalls?
4.
What are the benefits of long-term investment and capacity building?
5.
What would be the benefits and challenges of expanding this wildlife health monitoring system to other nations and regions?
Conflict of interest
The authors declare no conflicts of interest.
Further Reading
Addressing the risks of Ebola Virus Disease to humans and great apes. Available at: https://oneworldonehealth.wcs.org/Wild-Places/Africa.aspx (accessed 15 August 2023).
One Way to Prevent Epidemics: Monitoring Wildlife Mortality. Available at: https://www.pbs.org/wnet/nature/blog/covid-wildlife-mortality/ (accessed 15 August 2023).
Preventing epidemics by monitoring wildlife mortality. Available at: https://wcscongoblog.org/zoonotic-viruses-preventing-epidemics-by-monitoring-wildlife-mortality/ (accessed 15 August 2023).
Seifert, S.N., Fischer, R.J., Kuisma, E., Badzi Nkoua, C., Bounga, G.et al. (2022) Zaire ebolavirus surveillance near the Bikoro region of the Democratic Republic of the Congo during the 2018 outbreak reveals presence of seropositive bats. PLOS Neglected Tropical Diseases 16(6), e0010504. 10.1371/ journal.pntd.0010504.
Studying the Ecology of Ebola in Wildlife. Available at: https://oneworldonehealth.wcs.org/Wildlife/Bats/Bats-and-Ebola.aspx (accessed 15 August 2023).
Video: WCS Health Program Works with Communities to Prevent Ebola Outbreaks in the Republic of Congo. Available at: https://youtu.be/Si6Vi0GEsrM (accessed 15 August 2023).
Wildlife Mortality Monitoring Network for Human and Wildlife Health. Available at: https://panorama.solutions/en/solution/wildlife-mortality-monitoring-network-human-and-wildlife-health (accessed 15 August 2023).
References
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Cameron, K.N., Reed, P., Morgan, D.B., Ondzié, A.I., Sanz, C.M.et al. (2016) Spatial and temporal dynamics of a mortality event among central African great apes. Plos One 11(5), e0154505.
Figueroa, D.M., Kuisma, E., Matson, M.J., Ondzie, A.U., Bushmaker, T.et al. (2021) Development and validation of portable, field-deployable Ebola virus point-of-encounter diagnostic assay for wildlife surveillance. One HealthOutlook 3(1), 9.
Kuisma, E., Olson, S.H., Cameron, K.N., Reed, P.E., Karesh, W.B.et al. (2019) Long-term wildlife mortality surveillance in northern Congo: A model for the detection of Ebola virus disease epizootics. Philosophical Transactions of the Royal Society B 374(1782), 20180339.
Nkoghe, D., Kone, M.L., Yada, A. and Leroy, E.(2005) A limited outbreak of Ebola haemorrhagic fever in Etoumbi, Republic of Congo, 2005. Transactions of The Royal Society of Tropical Medicine and Hygiene 105(8), 466–472.
Olson, S.H., Bounga, G., Ondzie, A., Bushmaker, T., Seifert, S.N.et al. (2019) Lek-associated movement of a putative Ebolavirus reservoir, the hammer-headed fruit bat (Hypsignathus monstrosus), in northern Republic of Congo. Plos One 14(10), e0223139.
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© The Authors 2023. This article is licensed under a Creative Commons Attribution 4.0 International License.
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Published online: 11 December 2023
Issue publication date: 11 December 2023
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