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.

Keywords: Ethnoepidemiology; Ethnomedicine; Human-animal interactions; One health; Risk behavior; Traditional medicine; Wildlife; Zoonoses.

Fig. 1

Proportion of described zootherapies, including medicinal (blue; N = 172) and cultural (orange; N = 120) practices, involving different taxonomic groups (a) and body parts (b)

Fig. 2

Salience of animals used for medicine (a) and other cultural purposes (b). Plots show the frequency at which an animal was mentioned (x-axis) and the average rank assigned to each animal (y-axis) during free listing exercises with key informants (n = 50). The most salient animals are shown in the lower right-hand quadrant, indicating they were frequently listed and assigned a high average rank (1 = most important)

Fig. 3

Images of animal parts used for zootherapy: python oil made from fat and stored for use as body rub (a); fresh python fat mixed with local liquor or dried and used as lozenges (b); wild bird feathers for various cultural practices and decorations (c); pangolin scales being reduced to ashes for consumption to cure various illnesses (d); skull of dwarf crocodile hung in town hall for use during cultural festivities and/or charms (e); hornbill beak (f) and elephant teeth (g) traded for unknown medicinal use; monkey skull used as a vessel to prepare and administer medicine (h); and whole raw porcupine gifted to visitors with plantain to welcome them and bring good luck (i)