News flash!! Not only do animals get some of the same infectious diseases as humans, but they also suffer from some of the same chronic diseases, such as cancer. So what do humans and animals share that could be linked to the emergence and re-emergence of such diseases? Hint: it's part of the One Health triad...the environment!
A recent Newsweek article looks at how anthropogenic (=derived from man) activities contribute to the development of cancer in wildlife species. Researchers are concerned that human activities are altering the environment and, in turn, affecting the health of those animals who depend on a specific ecoystem for their survival. The Tasmanian devil has received much of the attention as their populations have fallen victim to devil facial tumor disease (DFTD), a quickly metastasizing cancer that attacks the face and neck and has a mortality rate of 100%. DFTD can cause severe facial disfigurement of devils and is spread by direct contact, which is frequently aggressive as their name would imply. Currently, the disease affects 65% of the remaining population of devils. If you do the math, you quickly realize that the population is facing extinction.
Researchers are partially attributing the rise in DFTD to the loss of genetic diversity on their island habitat of Tasmania. This phenomenon is sometimes referred to as the "population bottleneck." Animal groups are most successful when there is a great deal of diversity in their genes - that way, if an infectious agent arises, it is unlikely to wipe out the entire population. In the case of the Tasmanian devils, it is possible that human pressures (development, habitat destruction) have led to a decline in the populations and, in turn, less genetic diversity with which to adapt to changing conditions or new pathogens (i.e., the virus responsible for DFTD). The genes of future populations will reflect the narrowed genetic possibility for thousands of years.
Not only can virally-induced cancers such as DFTD be exascerbated by human behavior, but also cancers related to pesticides such as PCBs (polychlorinated biphenyls) and DDT. In one study reviewed in the Newsweek article, sea lions that died of genital carcinoma had an 85% higher concentration of toxic PCBs in their system than other sea lions. Beluga whales in Canada's St. Lawrence Estuary, lined with smoking stacks of aluminum smelters, are falling victim to cancer, especially of the gut. Marine mammals are especially at risk because of the dumping of toxins and pollutants into the waterways and oceans. Chemicals can accumulate and reach toxic levels. In the Canadian Estuary, the concentration of polycyclic aromatic hydrocarbons (PAHs), produced by those smelters, was 200 times higher in blue mussels than in surrounding areas. PAHs are long-proven carcinogens in both humans and animals.
The glass half full is this: pollution-induced cancer can be markedly decreased if the contaminants are taken out of the environment. The time is now to make changes that positively affect the environment - your health, as well as that of the devils, is counting on it.
http://www.newsweek.com/id/208917/page/1
Subscribe to:
Post Comments (Atom)
Great article! I firmly believe that pesticides are, in fact, one of the leading causes of many diseases in humans and animals. If the distinctive mark of a human vs. an animal is the fact that we can reason, then we should be able to reason that it is unwise for us to continue to use pesticides without full knowledge of consequences. I understand their 'place' but I cannot agree with you more that their use is deadly. The circle of life and the connection between humans, animals, and our environment are adversely impacted by the human use of pesticides. Continue to spread the word and get the message out that we desperately need to be conscious of our actions.
ReplyDelete