Devil vaccine a step closer

Greg Woods and Bruce Lyons.

Greg Woods and Bruce Lyons.

The results of an international study published recently in Scientific Reports has confirmed the fatal facial tumour disease that has decimated populations of Tasmanian devils in the wild for over 20 years, can be cured using immunotherapy.

Led by the University of Tasmania’s Menzies Institute for Medical Research, the study involved scientists from the Universities of Sydney, Southampton, Southern Denmark and Cambridge, as well as those from UTAS’s School of Medicine, the Walter and Eliza Hall Institute of Medical Research, and CSL Ltd.

The aim of the study was to ‘explore immunisation protocols to enhance protective responses against DFTD’, but due to devils’ endangered status, only a limited number of animals are available for research purposes. This five-year trial, that tested four immunisation protocols sequentially, was therefore restricted to nine healthy and genetically different animals, some of which had reached an advanced age. Continue reading Devil vaccine a step closer

Signs shown of genetic resistance to DFTD

Research by an international team of scientists, published at the end of August in the journal Nature Communications, shows two regions in the genomes of Tasmanian devils (Sarcophilus harrisii) appear to be evolving in response to the fatal facial tumour disease that has ravaged populations in the wild for almost 20 years.

Evolutionary geneticist Andrew Storfer from Washington State University, and geneticist Paul Hohenlohe from the University of Idaho, compared tissue samples collected from Tasmanian devils by Menna Jones over a 17-year period. An Associate Professor and wildlife ecologist at the University of Tasmania, Jones is credited with first identifying DFTD during the mid-1990s, and she subsequently established long-term field sites to study the animals. In less than 20 years populations of devils in the wild have declined by more than 80 per cent.

Jones, who is a co-author of the paper, said two small genomic regions were identified in the recently collected DNA samples from three sites: Narawntapu in Tasmania’s north-east, West Pencil Pine in western Tasmania’s Cradle Valley, and Freycinet, on the east coast. They all exhibited significant changes in response to the strong selection imposed by the disease. Continue reading Signs shown of genetic resistance to DFTD

New research on devils’ decline

It was curiosity about the reasons for Tasmanian devils’ low genetic diversity, a characteristic that was often noted but never fully explained in many of the papers she was reading, that prompted University of Tasmania PhD candidate Anna Brüniche-Olsen to discover why. The results of her study, the first to provide a ‘quantitative assessment of devil population size changes through time’ were published recently in Biology Letters.

Brüniche-Olsen and her team analysed available microsatellite data from 10 different locations across Tasmania to estimate the stability of devil populations over time, and they found evidence of declines that pre-date the fatal facial tumour disease that is currently ravaging the devils’ wild populations.

The results show four major events are likely to have influenced the current population distribution and low genetic diversity of Tasmanian devils. Environmental change around the last glacial maximum approximately 20,000 years ago was responsible for the first decline. Continue reading New research on devils’ decline

Reduced effect of Tasmanian devil facial tumour disease at the disease front

Pathogen-driven declines in animal populations are increasingly regarded as a major conservation issue. The Tasmanian devil (Sarcophilus harrisii) is threatened with extinction by devil facial tumor disease, a unique transmissible cancer.

The disease is transmitted through direct transfer of tumor cells, which is possible because the genetic diversity of Tasmanian devils is low, particularly in the major histocompatibility complex genes of the immune system.

The far northwest of Tasmania now holds the last remaining disease-free wild devil populations. The recent discovery of unique major histocompatibility complex genotypes in the northwestern region of Tasmania has raised the possibility that some animals may be resilient to the disease. The authors examined the differences in the epidemiology and population effects of devil facial tumor disease at 3 well-studied affected sites in eastern Tasmania and 1 in western Tasmania (West Pencil Pine). Continue reading Reduced effect of Tasmanian devil facial tumour disease at the disease front

Allorecognition in the Tasmanian devil (Sarcophilus harrisii), an endangered marsupial species with limited genetic diversity

Tasmanian devils (Sarcophilus harrisii) are on the verge of extinction due to a transmissible cancer, devil facial tumour disease (DFTD).

This tumour is an allograft that is transmitted between individuals without immune recognition of the tumour cells. The mechanism to explain this lack of immune recognition and acceptance is not well understood. It has been hypothesized that lack . . . → Read More: Allorecognition in the Tasmanian devil (Sarcophilus harrisii), an endangered marsupial species with limited genetic diversity