Vets Warn Some Md. Waterways Are Dangerous For Dogs

BALTIMORE (WJZ) -- Water and dogs go together in Maryland but this time of year, that can prove fatal.

Alex DeMetrick reports conditions are right in some waterways to sicken and kill dogs.

Dogs that take to water need to be careful where they swim right now because in places like the Magothy River in Anne Arundel County, tiny black mussels are reproducing in big numbers.

"[The reason] is salinity. So years that we have more rain and less salt, we seem to see the mussels," said Dr. Sally Hornor, an aquatic ecologist.

Then veterinarians start seeing very sick dogs who have eaten the mussels.

"It seems to be definitely related to the mussels," said Dr. Carl Rogge, a veterinarian. "It's a very, very severe vomiting and very lethargic."

"This is a great example of the way dogs come into contact with these mussels. You can see there's a lot of mussels here, really covered. It's always been liver damage that the dogs have had," Hornor said.

Which suggests the mussels contain some kind of toxin but tests have yet to find toxins in any of the mussels.

"I'm guessing it might be a toxin we just don't have a test for yet," Hornor said.

There's no danger to people and other animals who can eat the mussels without getting sick, but last year 20 dogs fell ill and half of them died.

"It's just a liver failure is what occurs, the fatal part of it," Rugge said.

Meaning this might not be the best time to go swimming for sticks.

The tiny black mussels do have an upside: prolific filter feeders, they clean the water, sometimes making it crystal clear.