Discovery

Transmitted tumors killing Tasmanian devils

February 10, 2006|By LOS ANGELES TIMES

They are never considered cute or cuddly, but Tasmanian devils are a cultural icon of Australia, right behind koalas and kangaroos.

Over the last decade, devils have been dying off in large numbers, felled by oral and facial tumors that prevent their eating, causing them to starve to death. In some areas, virtually all of the animals have died.

A study published in the journal Nature by researchers at Tasmania's Department of Primary Industries, Water and Environment offers this possible explanation: The animals are inadvertently transplanting tumor cells among themselves when they bite during fights and mating rituals.

The key came from an analysis of chromosomes in tumor cells, according to biologist Anne-Maree Pearse and colleagues. She found that chromosome patterns in tumor cells from the devils were identical to each other and grossly different from the devils' healthy chromosomes.

Such a complex arrangement of chromosomes could not have occurred independently in each animal, Pearse concluded. Instead, the tumor must have originated in one animal and been transferred to others. Apparently, the devils' immunological profiles are sufficiently similar that the tumor cells are not rejected.

At present, the best hope for fighting the outbreak is to remove diseased animals from the wild, scientists say. The island of Tasmania, an Australian state, is about 150 miles southeast of the continent across the Bass Strait.

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