Zootherapy as a potential pathway for zoonotic spillover: a mixed-methods study of the use of animal products in medicinal and cultural practices in Nigeria

Abstract

Background Understanding how and why people interact with animals is important for the prevention and control of zoonoses. To date, studies have primarily focused on the most visible forms of human-animal contact (e.g., hunting and consumption), thereby blinding One Health researchers and practitioners to the broader range of human-animal interactions that can serve as cryptic sources of zoonotic diseases. Zootherapy, the use of animal products for traditional medicine and cultural practices, is widespread and can generate opportunities for human exposure to zoonoses. Existing research examining zootherapies omits details necessary to adequately assess potential zoonotic risks. Methods We used a mixed-methods approach, combining quantitative and qualitative data from questionnaires, key informant interviews, and field notes to examine the use of zootherapy in nine villages engaged in wildlife hunting, consumption, and trade in Cross River State, Nigeria. We analyzed medicinal and cultural practices involving animals from a zoonotic disease perspective, by including details of animal use that may generate pathways for zoonotic transmission. We also examined the sociodemographic, cultural, and environmental contexts of zootherapeutic practices that can further shape the nature and frequency of human-animal interactions. Results Within our study population, people reported using 44 different animal species for zootherapeutic practices, including taxonomic groups considered to be “high risk” for zoonoses and threatened with extinction. Variation in use of animal parts, preparation norms, and administration practices generated a highly diverse set of zootherapeutic practices (n = 292) and potential zoonotic exposure risks. Use of zootherapy was patterned by demographic and environmental contexts, with zootherapy more commonly practiced by hunting households (OR = 2.47, p < 0.01), and prescriptions that were gender and age specific (e.g., maternal and pediatric care) or highly seasonal (e.g., associated with annual festivals and seasonal illnesses). Specific practices were informed by species availability and theories of healing (i.e., “like cures like” and sympathetic healing and magic) that further shaped the nature of human-animal interactions via zootherapy. Conclusions Epidemiological investigations of zoonoses and public health interventions that aim to reduce zoonotic exposures should explicitly consider zootherapy as a potential pathway for disease transmission and consider the sociocultural and environmental contexts of their use in health messaging and interventions.

Child and adolescent foraging: New directions in evolutionary research

“…[73][74][75] Zootherapy treatments for children's specific illnesses, such as use of extracts or mixtures made from animal parts and by-products as enemas to treat weakness or stomach pain in Cross River State, Nigeria, provide additional exposure pathways. 76 While in some settings adults may report not wanting their children to hunt, considering it a low-merit livelihood, 65 for children, hunting is a moment of freedom without supervision from adults and high risk behaviors may thus be done in secret. 59,60,64 For example, in Lassa fever endemic regions, children were more ready to admit eating town and bush rats when interviewed in the absence of an adult.…”

“…As recognized companions, protectors, and hunting partners, 70–72 dogs accompany children and may increase multispecies contact, thus potentially representing a complex pathway for virus transmission 73–75 . Zootherapy treatments for children's specific illnesses, such as use of extracts or mixtures made from animal parts and by‐products as enemas to treat weakness or stomach pain in Cross River State, Nigeria, provide additional exposure pathways 76 . While in some settings adults may report not wanting their children to hunt, considering it a low‐merit livelihood, 65 for children, hunting is a moment of freedom without supervision from adults and high risk behaviors may thus be done in secret 59,60,64 .…”

Human behaviors driving disease emergence

“…In turn, this practice may effectively increase the intensity of exposures among hunters and carriers, while simultaneously reducing the breadth of exposure among the village population, as meat from sponsored hunters' moves directly to local, regional, and international markets. Under the scenario of wildlife trade, parts that were historically low utility (e.g., great ape hands and pangolin scales are now) are traded for medicinal purposes 64 , which can dramatically increase their value and alter decision making under different currencies (i.e., energetic vs. economic return). Central place foraging models could, therefore be used to test the hypotheses that conservation polic market integration and engagement in wildlife trade alters optimal behavioral strategies for field processing and transport in a way that predictably affects the intensity and distribution of animal exposures.…”

A systematic review and analysis of health risks associated with zootherapeutic practices in Africa

“…Examples include several HIV strains that originally spilled over from African primates (Peeters et al, 2014), Mpox spilling over from African mammals (with the specific reservoir(s) still being investigated, e.g., Falendysz et al, 2023), or Brucella bacteria from cattle, a predominant issue in northern and eastern Africa (Mburu et al, 2020;Djaafri et al, 2022). So far, hunting, and the butchering and consumption of wild and domestic animal meat have been investigated as major mechanisms for spill over, while other transmission routes, such as zootherapy, remain under-researched (Paige et al, 2014;Friant et al, 2022;Milbank and Vira, 2022;Moloney et al, 2023).…”

“…Zootherapeutic practices are a major source of exposure to animal products and the pathogens they may carry (Alves et al ., 2021; Friant et al ., 2022). Each topical application, injection, inhalation, or ingestion of such animal products is therefore a potential mechanism for spill over (Plowright et al ., 2017; Friant et al ., 2022). Identifying zootherapeutic practices of higher epidemiological risk is thus crucial to develop sustainable alternatives that balance cultural significance and public health.…”