Baseline prevalence of Batrachochytrium dendrobatidis in a Central African rainforest amphibian community

Abstract

Batrachochytrium dendrobatidis (Bd), the fungal pathogen that causes chytridiomycosis, has been implicated in severe amphibian population declines and extinctions globally, yet the pathogen’s distribution in Central Africa remains poorly documented. Gabon hosts exceptional amphibian diversity, but previous Bd surveys have been sparse or geographically restricted. We establish a baseline of Bd occurrence in Ngounié province, southern Gabon, by screening 276 adults, representing 57 species of anurans. Prevalence of Bd was 11.2% overall (31 individuals, 18 species). We report the first Bd detections in Gabon for Cardioglossa leucomystax and Leptopelis notatus, and the first global Bd records for Amnirana amnicola and Arthroleptis taeniatus. Infection was strongly associated with adult ecology: semi-aquatic and aquatic species showed significantly higher prevalence than arboreal or terrestrial taxa. Infection intensity was generally low, though one Hyperolius tuberculatus individual exhibited a very high load (> 5 × 10⁵ ITS copies) without visible signs of disease. We confirm Bd presence in southern Gabon and highlight aquatic habitats as Bd hotspots, providing baseline data for future monitoring and conservation in the region. Keywords: Chytridiomycosis, Gabon, frog, reproductive mode, amphibian disease