Zoonotic diseases in wildlife from congo basin countries: A systematic review (1982-2026)

Abstract

Zoonotic diseases are a serious threat to human and animal health and challenge global health security. It is estimated that 60% of known infectious diseases and up to 75% of emerging infectious diseases are of animal origin and viral in nature (1-3). Over the last decades. the risk of emergence or re-emergence of zoonotic diseases has increased. driven by multiple factors including land use change. agricultural expansion. urbanization. habitat destruction. wildlife trade. globalization. and climate change (4, 5). Many of these drivers tend to intensify human and wildlife interactions. thereby enhancing the risk of emergence or re-emergence of viruses of epidemic or pandemic potential from wildlife reservoirs to humans (6). It has been estimated that 26.5% of mammals in the wildlife trade host up to 75% of the known zoonotic diseases; this proportion is much higher than that of non-traded wildlife and domesticated animals. It is thus likely that the virus that may cause the next pandemic is likely to emerge or re-emerge from wildlife (6). In 2024. the World Health Organization (WHO) updated its list of priority emerging pathogens of epidemic and pandemic potential based on criteria such as viral virulence. transmission dynamics. and availability of medical countermeasures such as vaccines. therapeutics. and diagnostic tools (7). This list is predominantly composed of zoonotic viruses such as filoviruses (e.g.. Ebola virus and Marburg virus). coronaviruses (e.g.. SARS-CoV and MERS-CoV). arenaviruses (e.g.. Lassa virus). paramyxoviruses (e.g.. Nipah virus). orthopoxvirus (e.g.. Mpox virus). and arboviruses (e.g.. Crimean Congo Haemorrhagic Fever virus. Dengue virus. Chikungunya virus. and Zika virus) (7). Wildlife species such as bats. rodents. and non-human primates (NHPs) play a key role in the maintenance and eventual transmission of these high-risk emerging zoonotic viruses (6). Bats are the most likely reservoirs for filoviruses (8). coronaviruses (9). and paramyxoviruses (10); rodents are established reservoirs for hantaviruses. arenaviruses and orthopoxviruses (11); and NHPs are highly involved in sylvatic transmission cycles of filoviruses and several arboviruses and they may serve as amplification hosts in spillover events (6). Africa is acknowledged as a major hotspot for viral zoonoses. causing recurrent outbreaks and clinically overlapping with endemic diseases such as malaria. which further complicates diagnosis and underestimates the true burden of viral zoonotic diseases (12). In Africa. the Congo Basin rainforest (spanning across six Central African countries: Cameroon. Central African Republic. Democratic Republic of the Congo. Equatorial Guinea. Gabon and Republic of the Congo) stands as one of the world’s most important regions for zoonotic disease emergence as it combines an extremely high mammal diversity. rapid change in ecology. and high human dependence on forest resources. Moreover. the Congo Basin has previously been the origin or early amplification spot for HIV. Ebola virus disease. Mpox virus. several arboviruses. and novel rhabdoviruses (4, 13-15). A global hotspot modelling analysis by Allen and collaborators revealed that highly forested tropical regions with high mammal richness and an active land-use change have heightened risk for the emergence of zoonotic diseases. emphasizing the Congo Basin as a critical priority for proactive surveillance (4). It is therefore necessary to summarize existing research of zoonotic diseases in wildlife from congo basin countries to inform future research. Therefore. this systematic analysis aims to provide the most comprehensive data on zoonotic viruses in wildlife from congo basin countries.