The amphibian chytrid fungus Batrachochytrium dendrobatidis in Sweden

even species studied, pool frog Pelophylax lessonae (63.64%) and green toad Bufotes variabilis (61.43 %) having highest prevalence. In central Sweden (Uppsala) Bd was found in three of five localities studied, representing the northernmost records of Bd in Europe. Here three species were sampled and the common toad Bufo bufo was the only species infected (prevalence 9.5 %). No individuals showing signs of chytridiomycosis were found in either of the areas. However, in inoculation trials using Bd isolated and cultured from green toads in southern Sweden, high mortality rates were found in infected B. bufo with the highest mortality in individuals from northern populations. The same pattern but with lower mortality rates was shown in Rana arvalis. The isolated strain of Bd belongs to the global pandemic lineage (GPL). An additional study showed that northern populations of R. arvalis have a lower variation in a major histocompatibility (MHC) class II gene –implicated to play a role in Bd resistance - than southern populations. These results indicate that Bd is much more widespread and common in Scandinavia than previously thought. They also suggest that high-latitude - amphibians may be more sensitive to infectious disease than those from more southern populations. This can be of considerable conservation concern if Bd is becoming more common at high latitudes.