Imported African animals released into the wild spread chytridiomycosis. When improved pregnancy tests were developed in the 1960s, the advance came with an unexpected side effect: a role in the spread of chytridiomycosis, a lethal fungal disease that has wiped out hundreds of species of frogs. A study published in PLoS ONE this week tracks the amphibian fungus that causes the disease, Batrachochytrium dendrobatidis, to an important reservoir in the Americas — African clawed frogs (Xenopus laevis)1. The frogs were used in pregnancy tests until the early 1970s, as it was known that the animals ovulated when exposed to a...