Tasmanian Devil Facial Tumour
Working with Principal Investigator David Phalen, (Wildlife Health and Conservation Centre, University of Sydney) and Stephen Pyecroft (Department of Primary Industries and Water in Tasmania), VOC has been awarded a Tasmanian Government Project Management Grant for their project Investigation into Chemotherapy Agents Effective Against the Tasmanian Devil Facial Tumour.
Pfizer Animal Health is kindly donating Cerenia to help the devils feel well after chemotherapy treatments.
Chemotherapy safety components by PhaSeal are a generous gift from Carmel Pharma.
Hill's Pet Nutrition has generously donated Prescription Diet a/d diet for the devils, which they love, and helps to maintain their condition and weight despite their disease and captivity.
VOC is providing our time for this project on a pro bono basis.
Devil facial tumour disease (DFTD) was first described in 1997 and now affects Tasmanian devils across more than 50% of their natural range, accounting for population declines of up to 80% in some areas. It is an aggressive, commonly fatal, disease for which no treatment has been reported. DFTD causes single or multiple large ulcerated soft tissue tumours on the face (especially in the mouth) and neck, metastasizing in 65% of animals to lymph nodes, lungs and less frequently other sites such as spleen and heart. However, mortality usually occurs within 6 months of onset due to the facial tumours causing dysphagia in the great majority of affected animals.
Despite the rapid progression of DFTD in the majority of Tasmania, Tasmanian devils from certain areas have not yet been affected. These animals may be genetically resistant to the disease, but this has not been established with certainty. Regardless, the death of large numbers of susceptible animals would be expected to reduce genetic variability and be a tremendous loss to the reproductive vigour of the species.
Recently Project Ark has established captive breeding populations of Tasmanian devils to meet the estimate that 500 breeding devils would be needed to maintain the genetic diversity of the species. Particularly if the future of the species relies on transplanted or captive populations, we believe that options for treatment of individual animals should be explored in addition to investigating the disease from a “population health” perspective.
One disease that we do have experience with is canine transmissible venereal tumour (CTVT) which, like DFTD, is readily transmitted by social behaviour. The anatomic distribution of DFTD lesions suggests the possibility that transmission of transplantable tumour cells is accomplished during “jaw-wrestling”, a common interaction in devils.
Interestingly, the chromosomal complement of CTVT is constant worldwide, with 58 to 59 chromosomes found in the tumour (compared with 78 for cells of normal dogs). Similarly, while normal Tasmanian devils have 14 chromosomes, DFTD cells in all affected animals studied contain only 13 chromosomes with deletions and unidentified marker chromosomes similar to those seen in CTVT.
The disease homology between DFTD and CTVT suggests that attempting chemotherapy, which is known to be highly successful against CTVT, may be worthwhile and successful against DFTD. A short course of chemotherapy cures 98% of dogs with CTVT, and we believe similar strategies may provide a substantial cure rate for Tasmanian devils afflicted by DFTD. Chemotherapy in animals is less intense than in humans, and associated with minimal side effects. We emphasize the priority of quality of life of these animals as being of paramount importance. If our hypothesis is correct, such treatment will result in low morbidity, allowing Tasmanian devils to be returned to their natural environment with their breeding capacity intact.