The African Clawed Frog is Queen

“Frog Once Used in Pregnancy Tests Spread Deadly Fungus”


A species of frog that was used from the 1930s to the 1950s in human pregnancy tests is a carrier of a deadly amphibian disease that is now threatening hundreds of other species of frogs and salamanders.

… The pathogen the frogs are spreading is a fungus called Batrachochytrium dendrobatidis, or Bd. It has led to the recent decline or extinction of 200 frog species worldwide, the researchers report. Researchers in 2004 found Bd in a museum specimen of an African clawed frog that dated to 1934. But the frog itself appears to be unaffected by the fungus.

“Evolution has run its course,” Dr. Vredenburg said. “The species probably at some point suffered, but the survivors have figured out ways to survive.”

For other species, the pathogen is “the worst disease in vertebrate history,” Dr. Vredenburg said. The disease infects the skin of frogs and salamanders and causes it to thicken 40 times greater than normal, Dr. Vredenburg said. Within a couple of weeks, the disease causes an electrolyte imbalance and the amphibians die of heart attacks, he said.

…Thousands of African clawed frogs were shipped from South Africa to labs and hospitals around the world before the middle of the 20th century. In those days, some pregnancy tests involved injecting a woman’s urine into a female frog. If the frog began ovulating within about 10 hours, there was a high likelihood that the woman was pregnant.

The frogs are no longer imported to the United States for pregnancy testing, though they are still used for scientific research.

African Clawed Frog female