Finding cause of elk hoof rot syndrome
March 12, 2014
Examples from history: They didn’t know what caused the disease so they called it, “Fort Bragg Fever,” or in Cuba, so they called it, “Cane field fever.” We could go on with “pea pickers fever,” “mud fever,” and many more—all were discovered to be infections with leptospires.
Is it the cause of hoof-rot disease?
These descriptive names have been attached to diseases all caused by one genus; Leptospira. Within this genus are 200-250 sub-types. These have names based on the production of antibodies. Each type is a “serovar.” So there are 200-250 serovars all producing different antibodies and toxins.
The genus is worldwide, has a spectrum of symptoms. Not one of these symptoms includes abnormal keratin hoof formation, and that is exactly what is found in elk hoof “rot.” It is misleading to call it “rot” because the hoof keratin is not “rotting.” It is normal. What we find is normal growth but under abrading of the hoof.
So what symptoms in elk can account for the hoof overgrowth? Are there symptoms that can be attributed to infection with leptospires? Indeed we see elk standing for hours and not moving even one step and holding up one foot. We see elk lying down for extended periods while other elk walk around feeding. When these lying get up they limp mostly with two or more feet involved.
You don’t have to take my word for it. A quote from the “Leptospirosis Laboratory Manual” of the World Health Organization as reported by Linda Anderson:
“Myalgia (muscle pain) is most commonly located in lower limbs and is so severe that even touching the muscle causes intense pain.”
This is a classical symptom common to a lot of cases of leptospirosis. Can anyone doubt that our elk have extreme leg pain that reduces walking, running, and even standing if more than one hoof is affected? Thus I contend that hoof overgrowth is the direct result of under abrading of normal hoof because it is too painful to walk. This pain is caused by infection with leptospires which incidentally is spread by contact with water contaminated with urine.
Every square foot of ground in SW Washington is wet more than half of the year and Lepto infects every species of mammal and is shed in the urine. The scientific term is “endemic”—it is somewhere in SW Washington all the time.
Elk walk in water every day and night, water that is contaminated with urine of other elk and domestic and wild mammals.
It is a common finding in leptospirosis to have involvement of the small blood vessels. That is also a finding in the examination of elk legs and feet as reported.
An important finding, however, came when leptospira were found in the kidneys of four elk—two with hoof overgrowth and two without hoof involvement.
Ah ha! Some have said, finding leptospires in animals that do not have hoof overgrowth proves that it doesn’t cause hoof overgrowth. That reasoning in science was rejected as illogical about a hundred years ago.
To add weight to this find of leptospires in the kidneys you don’t need to take my word for it. Again from the world’s literature:
“Isolation of leptospires from clinical specimens is the strongest evidence for confirmatory diagnosis.” Touché!
Some will argue that the numbers should be greater. There are valid arguments to explain this. Had one examined the animal alive over the course of the disease, the leptospires could have been found in every case.
Even so, culturing the organism is difficult. It requires special media and special handling. It can’t be stained with the regular stains and cannot be seen under the usual light microscope. Its symptoms mimic many other diseases so one can understand why initial attempts to diagnose the disease are missed 83 percent of the time.
But the characteristic of scientists also comes into play. Science is not based on loyalties and faith. It is based on facts and logic. It is historically consistent that to get an adversarial scientist to agree with an alternate concept is worse than pulling teeth without anesthesia (apologies to our dentist).
Lately many maneuvers have surfaced with great attempts to suppress presentation of all contrary information and to demean persons who do not agree with them.
Cure in the wild might be difficult but prevention might be easy.
Who will the public trust with such a project?
Editor's Note: A Skamokawa resident, Boone Mora earned a doctorate in public health from the University of North Carolina in 1978. He is retired from a career in public health in North Carolina. In 1977, he was a guest researcher at the National Center for Disease Control where he completed work begun earlier on developing and testing a simple test for leptospirosis.