How humans are now giving animals cancer
ANIMALS around the world are getting cancer as a result of human activities, scientists say.
Plastic pollution, light pollution, chemical spills, radiation and even feeding them fatty and sugary foods may be causing a rise in cancer among wild and domestic animals.
Causes of human cancer are well studied but the disease has been relatively overlooked in animals.
Researchers from Arizona State University’s School of Life Science compared humanity to a cancercausing virus.
One of the authors, Tuul Sepp, said: ‘We know some viruses can cause cancer in humans by changing the environment they live in – in their case, human cells – to make it more suitable for themselves.
‘Basically, we are doing the same thing. We are changing the environment to be more suitable for ourselves … having a negative impact on many species on many different levels, including the probability of developing cancer.’ In a paper published in Nature Ecology & Evolution, the researchers highlighted how human activities are taking a toll on animals.
This includes chemical and physical pollution in our oceans and waterways, and the accidental release of radiation into the atmosphere from nuclear plants.
Pesticide and herbicide pollution on farmlands, artificial light pollution, a loss of genetic diversity and giving animals human foods are all causing health problems.
The authors said the worldwide accumulation of microplastics – an issue highlighted by the Daily Mail – was a problem of growing importance, and may be a missing piece in the puzzle of why animals are increasingly getting cancer.
‘Microplastics are ingested by a wide range of species, potentially causing serious health threats and increasing cancer prevalence through their intrinsic toxicity … and their ability to absorb organic contaminants on to their surface,’ the researchers wrote. ‘For example, one of these contaminants, bisphenol A, possesses endocrine [hormonal] disruption properties and may contribute to the development of breast cancer and prostate carcinoma in adult humans as well as hepatic [liver] tumours in rodents.’
The authors said more testing was needed to examine whether plastic has similar carcinogenic effects on wildlife as on humans – but they suggested it could be contributing to an ‘increase in spontaneous tumours in marine environments’.
They cited many examples of humans causing the disease in animals, including chemical pollution in the Estuary of St Lawrence in Canada where 27 per cent of adult Beluga whales had cancer, as well as a high prevalence of cancer in sea lions in California.
Co-author Mathieu Giraudeau said the disease has been found in ‘all species where scientists have looked for it’ but that cancer in wild animals was ‘a completely ignored topic’.
Dr Tuul added: ‘To me, the saddest thing is that we already know what to do. We should not destroy the habitats of wild animals, pollute the environment, and feed wild animals human food.’
‘A completely ignored topic’