Biology Reference
In-Depth Information
1980, a large study of pet dogs showed that bladder cancer correlated with living in industrial
areas.
I arrived at the vet's knowing all of this, resigned. After fourteen years of living with me,
David was resigned to my fatalism, realizing that he couldn't stop my predilection for ima-
gining a bleak future. Solo doesn't do resignation, so he struggled against the biopsy needle,
believing the vet was going to do the unthinkable and trim his nails. Once he felt the thick
needle piercing his skin, which was no big deal to him, he relaxed completely and let her take
the cells and smear the slide. She didn't need a microscope for the first step.
The vet held the slide up to the light and then smiled. “Grease.” The most beautiful word
in the vet lexicon. Solo had a benign cyst.
• • •
Solo, like most American volunteer search-and-rescue dogs, hasn't had constant exposure to
toxins, compared with, for instance, the military working dogs deployed in the Middle East
and South Asia. And the military working people deployed there. People come back with a
variety of health problems that might or might not be related to what they were exposed to
while serving.
Dogs are one of the best warning systems we humans have, and not only as guard dogs.
Dogs can be both sentries and “sentinels”—an early-warning system for understanding hu-
man disease. The general idea of using animals as a human model in biomedical research goes
back to the ancient Greeks. But the idea of sentinel animals, which because of their shorter
life spans might help us understand how disease or toxicity affects humans, is a slightly newer
medical model. The earliest recognized sentinels were the canaries in the nineteenth-century
coal mines; they dropped dead from methane or carbon monoxide before the miners did. In
1952, cattle dropped dead in the smogs of England. Then the people died alongside them. In
the 1950s, in the tiny fishing village of Minamata, Japan, cats started exhibiting bizarre be-
havior, “dancing cat fever.” The cats sometimes fell into the sea and died, what villagers called
“cat suicides.” Then symptoms started showing in people. Every living thing in the village was
suffering from mercury poisoning, coming from an industrial plant making vinyl chloride
and sending its effluent into the bay.
Though dogs may be a great model for studying disease in humans, it is understandable
that the military might not leap to investigate diseases that military working dogs suffer over
their lifetime. In one of the few studies released on military dogs from the Vietnam War, both
dogs and servicemen had elevated risks for testicular cancer. Hypotheses about the causes
have ranged from exposure to Agent Orange or malathion to taking the antibiotic tetracyc-
line.
