PhD defense of Rachel LEONG on August 27th 2025

Rachel LEONG will defend her PhD thesis on August 27, 2025, at 10:00 a.m. (Reunion time), in the Charpak amphitheater at the University of Reunion Island, Moufia, Saint-Denis.

Exploring the human-bat interface –  implications for conservation and the potential for viral spillover in La Réunion.

Abstract: This thesis investigates the complex human-bat interface on Reunion Island through an interdisciplinary lens combining eco-epidemiology and socio-ecology. In the context of growing concern over zoonotic spillover and biodiversity loss, understanding human-wildlife interactions in localised, rapidly changing environments is critical. The study examines both ecological dynamics and human perceptions, exploring how knowledge, values, trust, and social processes shape human-bat relationships and risk perceptions, particularly regarding pathogen transmission and conservation attitudes.
From an eco-epidemiological perspective, the thesis explores cross-species viral transmission between the island’s endemic bat (Mormopterus francoismoutoui) and introduced synanthropic vertebrates such as rodents and pigeons. Molecular screening and phylogenetic analyses targeted three viral families - Paramyxoviridae, Coronaviridae, and Astroviridae. While no coronaviruses were detected in synanthropic mammals, astrovirus screening revealed high genetic diversity in M. francoismoutoui, with viral sequences closely related to those detected from rodents and birds . These results suggest repeated spillovers into bats, challenging the dominant narrative of bats as primary reservoirs. Building on these results, a community-level investigation examined key contact zones such as bridges, agricultural areas, and domestic sites. Preliminary evidence suggests that shared resources like water sources and guano-rich roosts may facilitate interspecies transmission. These shared habitats offer insights into how environmental and ecological factors structure spillover dynamics at fine spatial scales.
The socio-ecological dimension of the thesis focuses on how people perceive and interact with bats. Drawing on risk perception theory and environmental psychology, it analyses how personal knowledge, social norms, trust in institutions, and environmental values influence attitudes toward bats. Data were collected via interviews, surveys, and participatory mapping with a range of stakeholders, including researchers, conservation practitioners, and public health officials.
Using discourse, content, and social network analysis, the thesis maps dominant narratives and co-occurring themes to understand how conservation and risk discourses are constructed and circulated. Social Network Analysis reveals a semi-cohesive stakeholder network where a few central actors act as brokers, while many remain peripheral. This fragmentation limits collaboration and information flow. Social amplification processes magnify narratives such as fear of disease, shaping how people respond to bats. Conservation and health messaging often encounters resistance when it fails to reflect local values, emotional ties to wildlife, or trusted communicators.
The research emphasises the need to integrate local knowledge and relational values into conservation and public health strategies. It advocates for transdisciplinary approaches that combine ecological data with socially grounded perspectives to promote coexistence with bats. Ultimately, this thesis contributes to broader discussions on One Health, biocultural conservation, and socio-ecological resilience in island systems.

Members of the jury
Dr. Camille LEBARBENCHON |  Supervisor
Dr. Alice HUGHES |  Reviewer
Dr. Serge MORAND | Reviewer
Dr. Julie SHAPIRO | Examiner
Dr. François TAGLIONI | Examiner