Devil Facial Tumor Disease - Essay Example

Devil Facial Tumor Disease Introduction A spaniel-size marsupial known as Tasmanian devil that inhabits in the Tasmanian Island of Australia, has been hurling towards quenching in recent years due to being a dupe of a mysterious and bizarre facial cancer that disseminates similar to plague. DFTD (Devil facial tumor disease) is a devastating cancerous sarcoma that has an effect on 30 to 50 percent of Tasmanian devils. The advancement of ulcerated tumors all around the head and jaws of the animal is found to be the characteristics of disease. These extend into malignant tumors that disperse from the face of animal to the whole body. DFTD is exceedingly unusual as among the only three registered cancers that disseminate like a contagion, DFTD is one. It spreads from one animal to the other through biting and the infested animals typically expire within three to five months of the visibility of cancer. The main cause of death is found to be starvation and the collapse of its body functions. These tumors intervene with feeding, and therefore the infected animal leads to death due to starvation. Origin of Disease The DFTD is considered to have commenced in the Mount William National Park’s far north eastern region, from a prospect mutation. During 1996, Tasmanian devils with prominent facial tumors were snapped in the north-eastern Tasmania. After ten years, these features are found to be coherent with DFTD (Devil Facial Tumor Disease). Mode of Transmission The cancer, DFTD (Devil Facial Tumor Disease), is found to be transmitted from one animal to another through biting either during fighting, eating or mating. It develops quickly, congesting the mouth of animal and then disseminates to other organs. The illness has consumed sixty percent of entire Tasmanian devils population since it was initially detected in 1996, and it has been predicted by some ecologists that it could efface the complete wild population till 2035. Causes It was assumed by many scientists since the initial discovery of disease was made that it has been caused by a quickly dispersing virus. Since, viruses are the cause of fifteen percent of all types of cancers discovered in humans and are also common in animals. But then the later studies failed to validate the initial assumption of virus to be the cause. It was found that the chromosomes appeared different from those found in the normal cells of the animal and more similar to those found within the tumors growth in other Tasmanian devils. Dr. Belov along with her fellows compared Deoxyribonucleic acid samples from twenty six healthy and sick Tasmanian devils with Deoxyribonucleic acid of the tumors in 2007. They determined that cancer cells from diverse animals shared distinguishing genetic markers that were not detected in the animals. This work was further investigated by a team of American and Australian scientists by making use of more powerful technology of gene-sequencing to have a closer view of a numerous Tasmanian devils. In order to trace the initiation of the tumors, individual cancer cells were studied by the scientists and the recording were made for the active genes. A set of genes that were found to be usually active only in Schwann cells (nerve cells) was discovered by the scientists. It was argued by them that only one single Schwann cell in an individual animal was the found to be the progenitor of the entire DFTD (Devil facial tumor disease) cells (Zimmer). In areas where the disease is widespread, almost all sexually mature, of more than two years of age; Tasmanian devils turned infected and surrendered to the disease along with as young as a year old juveniles may also get infected. The resulting populations have a younger age-structure providing only a single breeding event to the females which used to have three normally. DFTD seems to be a cloned cell line, that is transmitted (usually by biting) in the form of an allograft from one devil to another and this transmission may be found similar to that in CTVT (Canine transmissible venereal tumor) and a communicable sarcoma infecting Syrian hamsters. The biology and prevalence of such vegetative cell parasites is typically unknown. The examinations of captivated Tasmanian devils suggest that this species has a tendency to develop tumors, specifically carcinomas. Nevertheless, DFTD is found to be significantly different from previously reported devil cancers, and to determine its etiology is vital for the development of strategies to manage the disease. DFTD seems like a soft tissue neoplasm cytologically, comprising of uniform shaped cells (round to spindle) with some specifying ultra-structural characteristics. Immuno-histochemistry proposes that these tumors are descended from neuroectoderm (Bostanci 1035). Pearse and Swift in the year 2006, examined DFTD cells from various devils in diverse locations, and ascertained that all of the diseased cells were genetically different and distinct from the cells of hosts while identical to each other from all examined Tasmanian devils. Hence it was proposed that the origination of the cancer resulted from a single individual and disseminate, instead of developing discretely within every individual. Subsequently it was witnessed by researchers that previously-uninfected devil was found to acquire tumors from wounds resulting from the bite if an infected devil, that confirmed that the disease spread through allograft. The modes of transmission were also verified to be scratching, aggressive sexual activity and biting amongst individuals (p.549). It has also been proposed that the infectious contagious cancer spreads due to the less diverse immune genes of Tasmanian devil (MHC class I and II). These genes are also present in the tumor cells so there are not regarded as foreign by the immune system. Al least four or more strains of the cancer have been detected and it is presumed to be evolving and thus predicted to turn more virulent. These evolving strains are also predicted to be a source of complication that may hinder the process of development of vaccines; also the gene mutation may result in dissemination of disease into other related and similar species such as the quoll. Treatment Vaccines for the cures of facial tumors in cats, dogs and horses were tested as a cure for Devil Facial Tumor Disease. However, these vaccines were found to be unsuccessful for the treatment of irradiated cancer cells. Conclusion DFTD (Devil Facial Tumor Disease) is one of the three kinds of cancers that are found to be contagious. The disease has caused a source of threat to the Tasmanian population and it has been predicted to annihilate the entire population within a period of 35 years. The main cause has been found to be genes located on Schwann cells and in usually transmitted by the bite of infected animal. Works Cited Bostanci, Adam. "A Devil of a Disease". Science 307.5712 [2005]: 1035. Print. Pearse, A. M. and Swift, K. "Allograft theory: Transmission of devil facial-tumor disease". Nature 439. 707 [2006]: 549. Print. Zimmer, Carl. “Scientists Discover Origin of a Cancer in Tasmanian Devils.” The New York Times. 31 Dec. 2009. Web. 10 Feb. 2013. Read More