Parasite Caused Frogs With Too Many Legs, Scientist Says

LOS LUNAS, N.M. -- Frogs in a Los Lunas pond are surfacing with either too many legs or too few, and one university researcher said he’s pinpointed the cause.


Worried viewers called Target 7 to find out if the water was contaminated and if it was harmful to humans.

Los Lunas officials didn’t know about the frogs until they were contacted by Target 7. Immediately, Parks and Recreation Director Michael Jaramillio closed off the pond and had the water tested.


Target 7 also conducted water tests, and reporter Anna Velasquez broke out in rashes after collecting samples.

Mason Ryan is an amphibian expert at the University of New Mexico who is investigating the frog deformities.

“In the big picture of the number of ponds and the number of frog species we have in this country, it's kind of a relatively rare event,” Ryan said.

Ryan said this is New Mexico’s first known case of bullfrog deformities. Out of the 178 frogs collected, he said 80 percent were deformed and all were juveniles.

“As with most stories in biology, it's a complex story with multiple things happening to cause this,” Ryan said.

Predators are responsible for the frogs that are missing legs, and a parasite called trematode caused three or more legs in some frogs, Ryan said.

“They have a complex life cycle where they go through a bird, into a snail, and they live in the water and then they enter the developing tadpole,” Ryan said.

Ryan said he believes something must have happened in the pond to trigger a spike in the parasite’s population.

“Our nitrogen level may have been high in the pond some time last year due to possibly and overspill of fertilizer,” Jaramillo said.


Jaramillo admits that a groundskeeper fertilized the grass around the pond and accidentally spilled some into the water.

“How much of it? They're thinking a couple pounds at the most, it wasn't like it was intentionally put in there,” Jaramillo said.

The amount of fertilizer was not enough to kill off the pond’s fish or other organisms, but may have been enough to cause the frogs’ deformities.