Emerging and re-emerging zoonoses include recently identified infectious diseases, diseases that have recently evolved from a subclinical state to a clinical syndrome, and previously known diseases that have recently displayed an increase in incidence or that have spread to new regions, hosts or vectors. 4 However, a disease may not be recognized as zoonotic at the first outset. The disease can spread undetected for a period of time depending on the incubation period (weeks to years), the epidemiological pattern of a subclinical disease to a clinical picture (the emergence of the symptoms depending on host or pathogen factors) or, if the number of cases, in both human and animal populations, is too small and undetectable during the initial stages of transmission to suspect a link between the two events. 7 Zoonotic EID outbreaks result from a now classically accepted phenomenon of concurrency of fundamentals and territories of emergence. Fundamentals include factors related to the host, the vector (if any), the pathogen, and favorable environmental factors (climate) although territories at risk are the product of human activity and high-risk behavior among the human population. For instance, territories (that is: city, district) with an inefficient disease detection system or a failure to control vectors and other carriers of diseases as well as man-made environmental changes (breakdown of the water system, deforestationy) will force an increase in contact between the human population and wildlife. 2, 8 Tropical forests form the ecosystem harboring the highest species richness of all terrestrial ecosystems and shelter almost 50% of the total global biodiversity. 9, 10 This includes wildlife, flora, multi-cellular organisms as well as an immense diversity of pathogens including bacteria, parasites and viruses. Actually, there is a latitudinal spatial gradient of pathogenic species richness increasing towards the Equator. 11 After the Amazonian Basin, the Congo basin in Central Africa has the world's second largest contiguous block of tropical rainforest, which encompasses many areas that remain largely undisturbed, due in large part to low human population densities and the remoteness of interior rainforests. 12 As wildlife host species richness is a good predictor for the emergence of zoonotic EIDs with a wildlife origin, 3 Central Africa in general, and Gabon in particular are privileged areas for the emergence of zoonotic EIDs.