Parasite blamed in beaver death

January 14, 2008 11:43:47 PM PST
A parasite known as raccoon roundworm appears to have killed the young Alhambra Creek beaver that was rescued Jan. 3 and rushed to the Lindsay Wildlife Museum's animal hospital in Walnut Creek.

A necropsy conducted at University of California, Davis, found that the young beaver, known as a kit, died from a species of the parasite bayliascaris, most likely raccoon roundworm, according to Sherrill Cook, director of external affairs for the Lindsay Wildlife Museum.

The young male beaver, which was also blind, had a huge load of the parasite in its brain, heart and liver. According to Cook, young animals are more susceptible to problems caused by the parasite than older animals because their immune systems aren't fully developed.

Raccoon roundworm eggs are commonly found in raccoon feces and can be transmitted when other animals eat contaminated soil or plants. The roundworm eggs then hatch and the larvae migrate through the body, causing damage to organs and muscle tissue, Cook said.

A Contra Costa County Animal Services officer brought the beaver to the Lindsay Wildlife Museum at about 2 p.m. on Jan. 3.

The beaver had been seen swimming in circles and bumping into things earlier that day and then appeared to be about to drown when a bystander jumped into the creek to save it.

The animal control officer who picked up the beaver and brought it to the animal hospital noted that it did not attempt to get away and appeared weak and lethargic and couldn't stand, according to the museum.

Nancy Anderson, the museum's veterinarian, examined the beaver and took blood samples and radiographs, but the results were inconclusive. The beaver received antibiotics, anti-inflammatory medication and fluids, but died at the hospital overnight.

The beaver had had what beaver watchers in Martinez called a "swimming limp" for some time before it died, Cook said.

The kit's death leaves two adults and two kits at the popular beaver dam in downtown Martinez, according to Martinez City Councilman Mark Ross, a member of the city's beaver subcommittee.