Batrachochytrium dendrobatidis (Bd)

What is batrachochytrium dendrobatidis?

Bd is a deadly amphibian pathogen that causes the disease called chytridiomycosis. The pathogen, Bd, is a  chytridiomycete (sometimes referred to as "chytrid") fungus that infects the skin of amphibians. In some species it causes little harm and does not result in disease while in others it causes inflammation and "super-growth" of the skin (hyperkaratosis) that then causes major problems with osmoregulation that can lead to death. This pathogen is significant because it causes outbreaks of disease in wild populations of amphibians and has ultimately resulted in hundreds of species going extinct. It is highly unusual for a pathogen to drive hosts to extinction. We believe that the emergence and spread of this pathogen may be contributing to the world's Sixth Mass Extinction (Wake and Vredenburg 2008).  For more information please see AmphibiaWeb's summary page for chytridiomycosis.  


Current research

Historical analyses of Bd globally

We have developed a technique that allows us to search for Bd infections in museum specimens. This technique is extremely useful because it essentially allows us to go back in time to determine where Bd might have come from and when and where it might have spread.  Then, we can see whether these data match declines of amphibians that occurred even before Bd was discovered (Bd was discovered in 1998, many amphibian declines occurred in the 1980s and early 1990s).

Factors associated with Bd susceptibility

We are interested in understanding why some amphibians are highly susceptible to Bd infections while others species are not.  We are investigating factors such as differences in the strain of Bd, differences in the skin microbiome of the hosts, host community richness and composition, abiotic factors, and host exposure to Bd or other pathogens.

Sharing data on pathogen distribution and dynamics

Working through AmphibiaWeb, we have helped develop the amphibian disease portal - a website where researchers can share data for all amphibian diseases.


HOW TO COLLECT a chytrid swab from a live frog: