Crayfish might aid the spread of the killer fungus (Image:Joel Sartore/NGS)

Crayfish are vulnerable to the same fungus that is killing frogs all over the world. The discovery helps explain how the disease spreads even after all the amphibians in an area have been wiped out. Worryingly, chemicals released by the fungus may alone be enough to kill.

Taegan McMahon of the University of South Florida, Tampa, and colleagues discovered infected crayfish in field surveys in Louisiana and Colorado. They found that up to 29 per cent of the animals carried the chytrid fungus Batrachochytrium dendrobatidis. Lab studies proved that crayfish can become infected and die, the first time this has been shown in non-amphibians.

Infected crayfish can pass the disease to tadpoles, and crayfish exposed to water from which the fungus had been filtered still died. McMahon says the distribution of crayfish around the world may explain why the fungus is so widespread.


She adds that it is “is certainly possible” that other invertebrates might carry the fungus. Her team are currently investigating this and are working on possible ways to stop the spread of the toxin.

“It’s very compelling, their evidence for crayfish as a disease vector and for a toxic effect secreted in the water,” says Trenton Garner at London’s Institute of Zoology.

PNAS, DOI: 10.1073/pnas.1200592110