Preliminary health screening and possible pathogen determination in a Bufo bufo (Linnaeus, 1758) (Amphibia: Bufonidae) population

The population of the common toad, Bufo bufo, on Jersey (Channel Islands, UK) has undergone a marked decline over recent years. Hypothesized causes for this decline include land use change, pollution, climate change and predation. We examined the carcasses of 97 wild adult common toads for gastrointestinal and pulmonary helminths. In addition, 31 adult toad carcasses were examined for the presence of ranavirus infection, and 212 wild common toads were examined for the presence of infection with the fungus Batrachochytrium dendrobatidis. Three nematode species Rhabdias bufonis, Aplectana macintoshii and Oswaldocruzia filiformis, and one species of cestode, Nematotaenia dispar, were identified. None of the animals examined tested positive for either B. dendrobatidis or ranavirus infection. Although this study should be considered a preliminary health screening, results lead us to suggest the decline of the common toad on Jersey is more likely to be driven by environmental factors rather than by pathogens.