Disease threatens tortoises

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Desert tortoises suffering from a cold-like illness
ASSOCIATED PRESS
Article Launched: 03/17/2008 03:04:41 AM PDT

RIVERSIDE -- Tortoises in the Southern California desert are facing an illness that carries symptoms of a bad cold but may be deadly to the federally protected species, experts said.

The illness, known as upper respiratory tract disease, has been found in some desert tortoises in the Mojave Desert northeast of Los Angeles.

The disease threatens tortoises' upper respiratory tracts and can cause a runny nose that hinders the animals' sense of smell, making it hard for them to find food. It can also cause an animal's eyes to bulge and run, leaving them caked with puss.

"They just look miserable," said Ileene Anderson, a staff biologist with the Center for Biological Diversity.

Like AIDS in humans, the illness suppresses tortoises' immune systems, making them vulnerable to repeated infection by various diseases.

The disease can be spread when tortoises meet and rub noses in greeting, Anderson said. They also touch heads in courtship, while male tortoises butt heads in dominance duels.

The disease is suspected of causing the deaths of tortoises of various species in the past two decades in California's Central Valley, as well as in Florida and other states.

The cause of the current outbreak is unclear. Some researchers believe wild tortoises were infected by captive animals released by pet owners. Domestic turtles and tortoises often carry the bacteria that causes the disease.

Others think the disease was dormant in wild tortoises and is breaking out now because the animals are weakened from drought and are having a difficult time finding food amid the development of their desert habitat.

"We don't have a way of knowing if it's something brand new that's really hitting the tortoises hard," said Roy Averill-Murray, desert tortoise recovery coordinator for the U.S. Fish and Wildlife Service in Reno. "Or if it's something the tortoise has had for eons, and if now the droughts and the impact from humans is making them more susceptible."

Researchers are trying to determine how quickly the illness is spreading. More infections have been found in tortoises living near urban areas, such as Barstow in San Bernardino County, than in pristine desert areas, said Kristin Berry, a wildlife biologist for the U.S. Geological Survey based in Riverside.
Later this month, crews will start relocating up to 1,000 tortoises whose habitat is being destroyed by the expansion of the U.S. Army's Fort Irwin Military Reservation in the Mojave Dessert.

Averill-Murray said the tortoises, which he is helping to move, are being blood-tested for the bacteria that cause the illness, and transmitters are being attached to the animals for further monitoring.

"Since we have to move the tortoises, we're trying to learn as much as we can about how the disease works," Averill-Murray said.