Cancer - a threat to wild animals!

[Guest guest]

Cancer is not new in animals or rather Veterinary Oncology is not a new subject

for that matter. There are many different types of cancer that are found in

animals, and symptoms are quite similar to those in humans. It generally happens

in animals that live longer than 10yrs. I once lost a dog to abdominal cancer

and he was 12 yrs old. So it wouldn't be wrong to say that it is one of the

leading causes of death in domestic animals like dogs and cats. So, wild animals

would also be prone to this disease.

But the exact effect of an animal's age on the incidence of cancer is not clear

as yet. In general, cancer is thought of as an old age disease. One must

hypothesize that, as cells continually divide as the life progresses, there is

an increased chance of genetic mutation due to cell division " accidents " and to

the actions of carcinogens (cancer-causing agents) on DNA. Also, depression of

the normal immune response in the older animal may play a part in the increased

incidence of cancer seen with advancing age.

As far as I know, Devils Facial Tumour Disease (DFTD) is contagious. I hope the

healthier devils are removed to better places to prevent their species being

wiped out completely! A recent research has shown that the low genetic diversity

in Devil immune genes is one of the key factors in making this cancer widespread

in Devils. Since the Devil is native to the island state of Tasmania, wouldn't

it be potentially inbred…..making it another factor for this cancer?

 

 

Warm Regards

Radhika Singh

 

http://timesofindia.indiatimes.com/Health--Science/Earth/Flora--Fauna/Cancer-a-m\

ajor-threat-to-wildlife/articleshow/4700766.cms

 

Cancer a major threat to wildlife

25 Jun 2009, 1220 hrs IST, ANI

 

 

LONDON: A recent study by the Wildlife Conservation Society (WCS) has revealed

that cancer not only touches the lives of humans, it is also a major threat to

wild animal populations.

 

" Cancer is one of the leading health concerns for humans, accounting for more

than 10% of human deaths. But we now understand that cancer can kill wild

animals at similar rates, " said Dr. Denise McAloose, lead author and Chief

Pathologist for WCS's Global Health program.

 

McAloose and her colleagues compiled information on cancer in wildlife and

concluded that cancer poses a conservation threat to certain species. The team

called for greater protection of animals and people through increased health

monitoring.

 

Cancer threatens the survival of entire species, McAloose said. For instance,

the Tasmanian devil, the world's largest carnivorous marsupial, faces extinction

from a cancer known as devil facial tumor disease. This contagious cancer

spreads among devils usually through fighting and biting. To save the species,

conservationists are relocating cancer-free Tasmanian devils to geographically

isolated areas or zoos.

 

The study suggests links between wildlife cancers and human pollutants, as well.

For example, beluga whales in the St. Lawrence River system have an

extraordinarily high rate of intestinal cancer - it is their second leading

cause of death. One kind of pollutant in the waters, called polycyclic aromatic

hydrocarbons, is known to cause cancer in humans. The compounds are suspected

carcinogens for beluga whales as well. Fish in other polluted waterways,

including brown bullhead catfish and English sole, also exhibit high levels of

cancer.

 

Viruses are another culprit. In some animals, viruses can induce cancers that

interfere with reproduction. Genital tumours in California sea lions occur at

much higher rates than previously documented, the paper shows. Dolphins, such as

the dusky dolphin and Burmeister's porpoise, found off South American coasts,

are also showing higher rates of genital tumours.

 

Other virus-induced cancers can affect an animal's eyesight or its ability to

feed. Green sea turtles suffer from fibropapillomatosis, a disease that causes

tumours to grow on the skin and internal organs. A virus is suspected to cause

these tumours.

 

Monitoring the health of wildlife can illuminate the causes of cancer in animal

populations and better safeguard them and us against diseases, McAloose said.

 

The research has been published in the July edition of the journal Nature

Reviews Cancer.