Public health risks of traditional zootherapeutic practices in Africa

Over five billion people globally, primarily rely on a plant- and animal-based pharmacopoeia. The topical application, injection, or ingestion of animal products - such as excreta, blood, or meat - likely facilitates the spillover of zoonotic pathogens. Certain practices use species known to be involved in the transmission of pathogens of public health relevance, such as filoviruses, poxviruses, or coronaviruses. This article aims to review zootherapeutic practices and the public health risk they entail for the African continent. We first conducted a systematic review of the scientific literature published until July 30th, 2023. We then created a categorical score reflecting the risk of zoonotic pathogen spillover for each recorded practice and compared this risk between regions and demographic groups. A total of 53 studies were included, half of which were published between 2020 and 2023. Nigerian practices were comparatively well documented. The mean risk score linked to practices occurring in eastern Africa was significantly higher than that of practices occurring in central Africa (p = 0.0008, p-adj = 0.008), western Africa (p = 2.5e-66, p-adj = 2.5e-65), and southern Africa (p = 2.55e-17, p-adj = 2.55e-16). Further, we found that children are overall at increased risk for pathogen spillover (p = 0.001, p-adj = 0.003), compared to adults. Where other forms of healthcare are inadequate or unavailable, traditional practices that balance cultural significance and public health risks should be encouraged. We suggest that local communities, traditional practitioners, researchers, and administrations should collaborate on (i) the elaboration of a pan-African collection of traditional practices, (ii) the regular monitoring of risks and benefits linked to such practices, including any comorbidities linked to hazardous preservatives, or the spillover of anti-microbial resistant pathogens; as well as (iii) the elaboration of culturally meaningful alternatives to the practices that entail higher risks than benefits.