Chytridiomycosis Prevalence
It has been suggested that B. dendrobatidis originated in Africa and subsequently spread to other parts of the world by trade in African clawed frogs (Xenopus laevis). In this study, 697 archived specimens of three species of Xenopus, previously collected from 1879 to 1999 in southern Africa were examined. The earliest case of chytridiomycosis was found in a X. laevis specimen from 1938. The study also suggests that chytridiomycosis had been a stable infection in southern Africa from 23 years prior to finding any infected outside of Africa.
Bullfrogs (Rana catesbiana), also widely distributed, are also thought to be carriers of the disease due to their inherent low susceptibility to B. dendrobatidis infection. The bullfrog often escapes captivity and can establish feral populations where it may introduce the disease to new areas. It has also been shown that B. dendrobatidis can survive and grow in moist soil and on bird feathers, suggesting that B. dendrobatidis may also be spread in the environment by birds and transportation of soils. Infections have been linked to mass mortalities of amphibians in North America, South America, Central America, Europe and Australia. B. dendrobatidis has been implicated in the extinction of the sharp-snouted day frog (Taudactylus acutirostris) in Australia.
A wide variety of amphibian hosts have been identified as being susceptible to infection by B. dendrobatidis, including wood frogs (Rana sylvatica), the mountain yellow-legged frog (Rana muscosa) the southern two-lined salamander (Eurycea cirrigera), San Marcos Salamander (Eurycea nana) Texas Salamander (Eurycea neotenes) Blanco River Springs Salamander (Eurycea pterophila) Barton Springs Salamander (Eurycea sosorum) Jollyville Plateau Salamander (Eurycea tonkawae) Ambystoma jeffersonianum, the western chorus frog (Pseudacris triseriata), the southern cricket frog (Acris gryllus), the eastern spadefoot toad (Scaphiopus holbrooki), the southern leopard frog (Rana sphenocephala), the Rio Grande Leopard frog (Lithobates berlandieri), and the Sardinian newt (Euproctus platycephalus).
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