The key to natural health is balance. As the body moves away from homeostasis or its normal way of going about its business, it becomes more susceptible to disease. When the body is placed in an unnatural state, unnatural outcomes will result because the body is pushed out of balance. When given antibiotics, the immune system suffers because the beneficial bacteria are destroyed. When given vaccines, allergies and other autoimmune diseases occur because the virus has been injected unnaturally into the body instead of entering through the usual pathways; the nose and mouth. When fed unnatural foods like grains, the body has to produce excesses of insulin and diabetic pets are the result.
Most dog owners who read our magazine and these online articles understand this concept. One example of natural balance dog owners might not be aware of is that of intestinal worms. Dog owners are often searching for ‘natural’ dewormers but ridding the body of worms may not be that natural at all. In the quest to make dogs worm free, vets and dog owners may be contributing to the increase in allergies and bowel diseases in dogs.
Researchers are currently noticing that organisms like the millions of bacteria, viruses and especially worms that enter the body spur the development of a healthy immune system. The therapeutic use of whipworms to treat autoimmune disorders like Crohn’s disease or severe allergies in humans is called helminthic therapy.
Medical researchers like Dr Joel Weinstock, director of gastroenterology and hepatology at Tufts University, are trying to discover the science behind that mechanism. Weinstock says that modern society — in the quest for proper sanitation and clean drinking water — may have destroyed many of the natural intestinal parasites that evolved alongside humans.
This so-called “Old Friends Hypothesis” (first put forth in the mid-1980s) says that public health improvements in the 20th century have corresponded to a simultaneous increase in auto-immune disorders, an increase not seen in the underdeveloped world where parasites are common.
“Many of these worms are bioengineered for humans,” Weinstock told Discovery News. “We adapt to them; they adapt to us. It becomes like an organ, just like your heart, your spleen or your liver.”
Several continuing studies suggest that worms may help to redirect an immune system that has gone awry and resulted in autoimmune disorders, allergies and asthma.
Studies conducted by Dr Weinstock in Boston, and Dr David Elliott, a gastroenterologist and immunologist at the University of Iowa, indicate that intestinal worms, which have been all but eliminated in developed countries, are “likely to be the biggest player” in regulating the immune system to respond appropriately. He added that bacterial and viral infections seem to influence the immune system in the same way, but not as forcefully.
Most worms are harmless, especially in well-nourished people, Dr Weinstock said.
“There are very few diseases that people get from worms,” he said. “Humans have adapted to the presence of most of them.”
In studies in mice, Dr Weinstock and Dr Elliott have used worms to both prevent and reverse autoimmune disease.
How may worms affect the immune system? Dr Elliott explained that immune regulation is now known to be more complex than scientists thought when the hygiene hypothesis was first introduced by a British epidemiologist, David P. Strachan, in 1989. Dr Strachan noted an association between large family size and reduced rates of asthma and allergies. Immunologists now recognize a four-point response system of helper T cells: Th 1, Th 2, Th 17 and regulatory T cells. Th 1 inhibits Th 2 and Th 17; Th 2 inhibits Th 1 and Th 17; and regulatory T cells inhibit all three, Dr Elliott said.
“A lot of inflammatory diseases — multiple sclerosis, Crohn’s disease, ulcerative colitis and asthma — are due to the activity of Th 17,” he explained. “If you infect mice with worms, Th 17 drops dramatically, and the activity of regulatory T cells is augmented.”
Hopefully, these studies will spur more research into the relationship between dogs and parasites. It might not be wise to allow our dogs to become infested with parasites, but once again, nature loves balance and a few worms might actually be beneficial for humans and for dogs.