Emerging pathogenic strongylid infections in Virunga Massif mountain gorillas: Role of environmental stressors

Abstract Conservation success stories, such as the recovery of the isolated populations of mountain gorilla ( Gorilla beringei beringei ), are increasingly threatened by emerging health challenges. In the Virunga Massif, strongylid‐associated gastrointestinal disease has been linked to significant morbidity and mortality of mountain gorillas, posing a critical threat to this population's long‐term survival. Using metabarcoding of faecal samples (~65% of the population) and spatial and habitat analyses, we examined the composition and drivers of strongylid nematode communities and their role in clinical disease emergence. We identified Hyostrongylus nematodes, known pathogens in suids, as the primary contributors to gastric lesions observed in necropsied gorillas. Spatial variation in strongylid communities is correlated with environmental gradients, indicating that environmental factors such as climate and vegetation play a significant role in shaping strongylid community composition. Additionally, limited genetic diversity resulting from historical population bottlenecks may negatively impact the health of gorillas affected by parasites. Our findings suggest that the high absolute abundance of pathogenic Hyostrongylus is concentrated in specific high‐altitude regions, aligning with observed cases of severe gastritis. Synthesis and applications . These findings highlight an emerging health threat for mountain gorillas, with implications for other isolated wildlife populations facing similar ecological and evolutionary pressures. The study calls for continued monitoring of parasitic diseases in wildlife populations, especially those in fragmented habitats with limited capacity for expansion, to mitigate potential risks to their conservation.