The chytrid fungus, _Batrachochytrium dendrobatidis_, is a deadly pathogen that has caused the decline and extinction of hundreds of amphibian species around the world. This fungus causes chytridiomycosis, a disease that affects the skin of amphibians, disrupting their ability to absorb water and electrolytes. Chytridiomycosis is spread through direct contact between infected and uninfected amphibians, as well as through contact with contaminated water or soil.

A new study published in the journal _Science_ sheds light on how chytrid fungus spreads and kills amphibians. The study, led by researchers at Imperial College London, found that the fungus produces a toxin that affects the function of the amphibian heart. This toxin, called _Batrachochytrium dendrobatidis toxin_ (BdTX), causes the heart rate of amphibians to decrease and their blood pressure to drop. This can lead to heart failure and death.

The researchers also found that BdTX is more toxic to some amphibian species than others. This may explain why some amphibian species are more susceptible to chytridiomycosis than others.

The discovery of BdTX could lead to new treatments for chytridiomycosis. By targeting the toxin, researchers may be able to develop drugs that can prevent or treat this deadly disease.

Here are some key findings from the study:

- The chytrid fungus produces a toxin that affects the function of the amphibian heart.

- This toxin, called Batrachochytrium dendrobatidis toxin (BdTX), causes the heart rate of amphibians to decrease and their blood pressure to drop.

- This can lead to heart failure and death.

- BdTX is more toxic to some amphibian species than others.

- The discovery of BdTX could lead to new treatments for chytridiomycosis.

This study provides new insights into how chytrid fungus spreads and kills amphibians. The discovery of BdTX could lead to new treatments for chytridiomycosis, a deadly disease that has caused the decline and extinction of hundreds of amphibian species around the world.