Facial Tumour Disease
Devil Facial Tumour Disease is a term used to describe a fatal condition in Tasmanian devils which is characterised by the appearance of obvious facial cancers. The tumours or cancers are first noticed in and around the mouth as small lesions or lumps. These develop into large tumours around the face and neck and sometimes even in other parts of the body. Adults appear to be most affected by the disease - males the first affected, then females. Badly affected devils may have many cancers throughout the body. The Tasmanian Government has nominated the devil for listing as vulnerable under the State’s Threatened Species Act in response to field data indicating the devil population had dropped between 33 and 50 per cent from a 1990 peak of 130000. This spectacular disease was first detected in far north east Tasmania in the mid 1990s. It has now been recorded over much of the eastern half on Tasmania and seems to be spreading. The apparent boundaries of the disease are not yet clearly known. The disease is fatal and effects the majority of devils. The infectious mechanism is not yet clear although infection rates suggest it is possibly highly infectious between devils. So far, the disease has only been detected in wild devils on the Tasmanian mainland. However, a disease with superficial similarities has been detected in wild koalas on mainland Australia and in cats and pigs. A major investigation of the disease and its impacts on wild populations is currently underway. All the work being done is vital in identifying management strategies to ensure the ongoing survival of the Tasmanian devil. If devil numbers continue to fall at the large rate indicated above, there is a concern it may lead to increased numbers of other non-native species such as feral cats and the fox, recently thought to be introduced to Tasmania. Mooney (2004, p34) says devils would normally act as a buffer against foxes through competition for carrion and predation on fox cubs. |
Signs of Facial Tumour
Knowing about Facial Tumour early..... | Facial Tumour Disease Resources..
| Devil Facial Tumour Disease was first noticed in the north-east of Tasmania in the mid-1990s but has become more prevalent in recent times in other areas of the state. In the areas already surveyed, the disease has the most dramatic effect in those with high-density populations with up to 100% mortality of resident devils in 12-18 months. In lower density areas, population decline has been less marked. The disease appears to kill most devils once they reach adulthood, with a few juveniles affected. In the medium term, there is some population recovery but populations are made up mostly of young animals. |
| DFTD begins as lesions and lumps around the mouth. The lesions and lumps develop into cancerous tumours that spread from the face to the entire body. The tumours interfere with feeding, and the affected animal may starve to death. Using cultures of the cancerous tissue to study the condition, researchers have identified the cancer as neuroendocrine in nature, and all cancer cells have identical chromosomal rearrangements. A virus was initially thought to be the cause of DFTD, but no evidence of such a virus could be detected in the cancer cells. The cancer cells themselves are an infective agent, with transmission of the disease occurring by biting, feeding on the same material, and aggressive mating. Final confirmation of this came when researcher Anne-Maree Pearse and colleagues found an infected animal that had a chromosomal abnormality in its nontumorous cells that did not appear in its tumour cells, proving that the tumour cells could not be descended from the animal's own cells. No definitive conclusion can be drawn at this stage from the results of the histology. However the use of immunohistochemistry has shown that the most consistent tumour type isolated appears to be of a neuroendocrine origin. Cytogenetics work has established the Normal Tasmanian Devil karyotype and the chromosome rearrangements of the tumour. This has led to the hypothesis that DFTD may be directly passed from animal to animal by implantation of the cell line during fighting and biting. |
Facial Tumour
More about Facial Tumour
| Where is Facial Tumour Worst? Devil Facial Tumour Disease (referred to as DFTD) is the name given to a fatal condition that is afflicting a significant portion of the native population of Tasmanian devils. The condition first becomes noticed as small lesions or lumps around the mouth that develops into large tumours predominantly around the face and neck, but sometimes in other parts of the body as well. DFTD was first reported in the mid 1990’s and has now been confirmed in most areas throughout Tasmania except for north-west and west coast devil populations. It is having a major impact in areas with high-density populations, and is predominantly affecting the adult populations. The disease does not usually become apparent in devils until they are at least two years old. The cancers affect the capability of the devil to ingest food thereby weakening the animal and making it more difficult for it to compete with other animals for food. Evidence suggests that animals appear to die within three to five months of the lesions first appearing, from starvation and the breakdown of body functions. There are three well-known types of malignant skin tumours. In all of them the ultraviolet rays from the sun plays a significant etiological role. The most common one is basal cell carcinoma or basaloma, which does not metastasize and is the more benign of the three types. Sometimes it grows very aggressively with a great tendency for recurrence, and destroys underlying tissue, bone, cartilage etc., with pronounced cosmetic and functional defects as a consequence. A facial tumour disease is continuing to ravage Tasmania's wild devils, with almost half of the devil population believed lost to the disease. Fears the disease is spreading have been realised, with 3 new cases discovered in the south of the state. Malignant melanoma is the type of tumour presently increasing the most in incidence. It spreads both through lymphatic pathways and hematogenously, and in the long term has a bad prognosis, especially if the tumour is not discovered until it has grown deep into the skin. It is usually pigmented by the melanin in the melanocytes. This may not always be the case, as so-called amelanotic , i e not blue or brown colored, melanomas exist. The disease has now spread across 65 per cent of the state, with 3 new cases discovered in southern Tasmania. The disease is across the eastern part of the state and extends as far west as the Cradle Valley, and also down into the south of the state. To date we haven't recorded the disease on the west coast or in the far north-west, so it's in the eastern parts of the state that the disease is having the greatest impact. |
 |