Decreases in chimpanzee respiratory disease signs and enteric viral quantity following implementation of anthroponotic disease prevention protocols at a long-term research site

Abstract

Diseases transmitted from humans (i.e., anthroponotic diseases or anthroponoses) are among the leading causes of ill health and mortality for wild chimpanzees (Pan troglodytes). Although various health and hygiene protocols have been proposed to reduce the risk of anthroponotic diseases to chimpanzees, evidence for the efficacy of these protocols remains largely anecdotal. Following a fatal outbreak of anthroponotic respiratory disease among chimpanzees at the long-term field site of Ngogo, Kibale National Park, Uganda, research personnel implemented more stringent disease prevention protocols (e.g., use of face masks in the presence of chimpanzees). Furthermore, in response to the COVID-19 pandemic, a 7-day quarantine period prior to any exposure to chimpanzees was implemented for all Ngogo research personnel. In this study, we used longitudinal data to determine whether more stringent disease prevention protocols were associated with changes in the frequency of respiratory disease signs exhibited by Ngogo chimpanzees. Chimpanzees were observed to cough less frequently following the implementation of more stringent disease prevention protocols compared to the period prior. Coughing frequencies were even lower following the implementation of the quarantine period. To examine whether chimpanzees were exposed to human-origin viruses, we analyzed 60 fecal samples collected before and after the implementation of stringent disease prevention protocols using viral metagenomics. No clearly anthroponotic viruses were identified outside of respiratory outbreaks. However, we found a reduction in overall viral shedding following the implementation of stringent disease prevention protocols. Overall, our data suggest that programs designed to reduce anthroponotic transmission to great apes are worthwhile.