Tick Borne Disease
By: Lew Olson,
PhD Natural Health, LMSW-ACP
Dedicated To Gil Ash's Thunder on His Birthday
(He would have been six on September 2nd)
A Note from Lew . . .
I would like to personally thank Gil for writing
this very wonderful article on Ehrlichia; its cause, its
symptoms, testing for it, and treatment. I know this was very
hard for her to write after the loss of her beloved Thunder to
this disease, and we can only hope that the information included
here will help other dogs and their owners.
Newsletter article written by Gil Ash
http://nowhereelse.homestead.com/Thunder.html
In the late 1960's, military dogs in Vietnam began dying in the
hundreds from what was then called canine hemorrhagic fever.
CHF, the name used by the vets trying to save them, was
graphically descriptive of its effect on the dogs whose bone
marrow simply stopped making red and white blood cells, but it
said nothing about the organism causing it. We know now that
the disease that was killing those tracker dogs was Ehrlichiosis
canis and it is carried by ticks.
Ehrlichiosis spread rapidly after 'Nam. Unlike Lyme disease,
which is primarily restricted to a fairly small area of North
America and is crippling but seldom fatal, Ehrlichosis is a
threat to dogs over a vast geographic area; it has stricken dogs
in every one of The United States and on nearly every continent
and it is always fatal if a diagnosis is not detected in time
for the damage to be reversed.
It can silently undermine the health of its host for years until stress or
some other factor brings it to light, then the dog can die with a
suddenness shocking to the grieving owner who may never
have realized anything was wrong. Perhaps for that reason, it
is practically unknown among dog owners and the level of
knowledge about it among veterinarians is abysmal.
WHAT IS IT?
Ehrlichia are parasitic organisms which are something like a
virus but are classed with bacteria. They attack the bone
marrow, crippling its ability to make the white blood cells
(leukocytes) which are an important component of the immune
system.
"Once a human or animal is stricken with Ehrlichiosis, white
cells die off faster than the bone marrow can replace them.
These dead cells migrate primarily to the spleen which enlarges
as a result. Frantically, the bone marrow works to form new,
healthy cells. In its haste, it sends out immature cells which
do not work efficiently. Quite often these immature cells are
almost indistinguishable from those seen in leukemia patients.
Advanced Ehrlichiosis is, in fact, often misdiagnosed as
leukemia or lymphosarcoma."
www.srv.net/~cdm/Dale/ehrlichia.html
Since that was written, indications have grown stronger that
Ehrlichiosis either causes cancer or sets up the conditions for
cancer to develop. It has been suggested that dogs ostensibly
cured of it should be tested for cancer four years after
titering clear as so many seem to develop cancer of one form or
another in that time frame. This is no big surprise to those of
us who have seen our dogs come down with serious illnesses after
or during - their infection with Ehrlichiosis since, with an
immune system that is essentially out of commission, the dog is
defenseless.
TRANSMISSION
Ehrlichiosis is transmitted by the nymph and adult of the brown
dog tick, rhipicephalus sanguineus, and the adult deer tick,
dermacentor variabilis. Once an infected tick has attached and
begun feeding, the disease is pumped into the dog with the
tick's saliva. Saliva keeps the blood from coagulating so the
flow of food for the tick is constant and there is some
conjecture that tick saliva contains a substance which prevents
the immune system from recognizing an invader soon enough to
ward it off. At any rate, the deadly inoculation continues
until the tick is sated and detaches.
Transmission of Erhlichiosis takes from 24 to 72 hours, though
on rare occasions it has happened in less than twelve.
One strain of this difficult and hard to pin down disease is not
carried by ticks. E. risticii, which has been renamed
neorickettsia risticii to reflect its close relationship to the
organism that causes the deadly Pacific Salmon Poisoning
Disease, is transmitted by the larvae of flukes that live on
river snails. Once it infects the dog, however, it acts like
every other strain of Ehrlichiosis and requires the same
treatment.
Eight to twenty days after infection, in the acute stage of the
disease, the dog may show symptoms such as a discharge from the
nose or eyes, fever, lethargy, depression, enlarged lymph nodes,
disinterest in food or difficulty breathing. Or it may not.
The acute stage is short, about four weeks at the outside, and
many people never notice anything to alarm them.
Unfortunately, this is the stage at which it is most easily cured.
The disease then passes into the sub clinical stage, a term that
simply means no symptoms are evident and it may stay in this
stage for up to five years while the immune system is steadily
undermined. Cure is not as easy but still possible for most
dogs at this point.
When Ehrlichiosis becomes chronic, damage is usually extensive
and curing a dog of it is difficult. Dogs may begin to bleed
from the nose, they may develop edema (swelling), blood
disorders such as leukopenia (an abnormal decrease in white
blood cells), thrombocytopenia (a decrease in the number of
platelets in the blood which can lead to increased bleeding as
the blood loses the ability to clot) and abnormally high levels
of antibodies in the blood.
With the immune system effectively destroyed, almost anything
from vague symptoms that go nowhere to kidney failure, cancer
and inflammation of the brain can be the result. German Shepherd Dogs
are hit particularly hard and in the late chronic stage may develop fatal
hemorrhaging. Cross infections with other strains of Ehrlichiosis or
other TBDs are common.
TESTING
There are various tests that can be done to detect Ehrlichiosis.
The IFA, or Indirect Fluorescent Antibody test, looks for the
actual organisms in the blood. The PCR, or Polymerase Chain
Reaction test, looks for DNA evidence of Ehrlichiosis; false
positives and negatives are possible with it and it should be
run by experts. The western blot is capable of giving further
information on specific species.
The Snap3 Dx Test which looks for signs of heartworm, Lyme
disease and E. canis can tell you nothing about any strain other
than E. canis. If the dog has one of the other forms of
Ehrlichiosis, it will not be detected and a negative titer will
not mean the dog is not infected with one of the other strains.
A positive titer for Ehrlichiosis with this test, however,
confirming a diagnosis, can be helpful since the treatment for
E. canis will work against any form of the disease.
E. canis, the most common form of the disease,
will cross-react with E. chafeensis. Separate tests must be run
for the other strains of Ehrlichiosis: E. platys, ewingii, equi, and
risticii.
A negative IFA does not mean that a dog is free of Ehrlichosis.
In the acute stage, dogs may test negative because antibodies
have not had time to form. In the chronic stage, the immune
system may be exhausted and there may no longer be any
detectable antibodies.
Diagnosis is not testing alone but the evaluation of the
veterinarian; if a negative titer doesn't make
sense in the picture he/she is seeing, the dog should be put
on doxycycline and if it improves, the diagnosis is confirmed.
TREATMENT
Misdiagnosis is a huge problem with tick disease because it is
so often mistaken for something else entirely and misdiagnosis
in this case is more than ordinarily dangerous. If there is the
slightest hint that a dog has TBD, it should be treated for that
first; if the dog improves, a diagnosis of tick disease is
confirmed and any other condition should be treated with that in
mind. Things can get sticky if the dog also has a concurrent
blood disorder like thrombocytopenia which is treated with an
immune suppresser like prednisolone; the vet then has to walk a
very fine line in deciding how much to prescribe
since steroids can kill a dog with Ehrlichiosis or any other form of TBD.
It can, however, be done. Steroids can also allow
cross-infection with babesiosis to become active, producing
another complication. Anabolic steroids, though not dangerous, have not
proven particularly effective since they stimulate the bone
marrow and often enough, there is nothing left in the bone
marrow to stimulate.
The drug of choice for Ehrlichiosis is doxycycline. The Merck
Veterinary Manual recommends giving doxycyclineat a dosage of
10 milligrams per kilogram of body weight every day for a period
of ten days to two weeks. The vets who deal with tick disease
most often, however, have found that a higher dose of twice that
amount - 10mg given every 12 hours for six to eight weeks - is
more effective at stopping Ehrlichiosis (as well as Rocky
Mountain Spotted Fever and Lyme disease) and preventing its
recurrence.
Their recommendation is still controversial but among most dog
owners who have suffered along with their dogs through the
ravages of this disease, there is no hesitation
about following it. The thinking is that disease resistance is
more likely to build with low doses of antibiotic -- hit it hard
the first time out.
Outward signs of improvement, if they are going to happen, are
almost immediate, and fortunately, doxycycline, a semi-synthetic
tetracycline antibiotic, is relatively benign, has few, rare
side effects, and can be given with food, making it less likely
that the dog will vomit it up. If that should happen, the twice
daily dose can be adjusted so that the dog can get it more often
in smaller amounts less likely to irritate the stomach. In the
event a dog cannot tolerate doxycycline, there are other drugs
that can be substituted which vary in their effectiveness and
Imizol may be the best of these for all but E. platys.
Imizol (immidocarb diproprionate) is not approved by the FDA for
the treatment of Ehrlichiosis and is used off-label but it can
be effective in knocking out stubborn cases of the disease.
However, it is imperative that the vet read the product label
and balance risk against benefit for dogs that
have impaired lung, liver or kidney function.
Of the four major tick diseases in The United
States, Ehrlichiosis is the most widespread and probably
the most dangerous. As noted above, Lyme disease seldom
kills but may cripple the dog if not treated. Rocky Mountain
Spotted Fever comes on quickly and can kill quickly, infection
occurring in as little as six to ten hours after the tick begins
feeding; illness may become apparent in as little as two
days up to two weeks, though a week is more common. Babesiosis
can be fatal but it does not seem to be as prevalent as Ehrlichiosis
and so is probably not as great a risk to most dogs. But all should be
taken seriously and treated promptly for the
health, for the life, of the dog.
Ehrlichiosis, like all tick disease, is a huge and complicated subject;
what you have read barely scrapes the surface and if
any of the above information is incorrect or out-dated, it is
not intentional. Nothing about this disease is easy to be certain about.
There is just not enough funding for research and some of what is
known about it comes from experience and
anecdotal evidence, something which makes it difficult to
convince many veterinarians that it is epidemic, that it can
cause or appear to be diseases which they think they see, yet
which do not respond to the approved treatments for them, or
that they should even test for TBD. Strangely, if tests are run
and dogs are found to have Ehrlichiosis, they are then often
reluctant to follow the advice of veterinarians experienced in
dealing with it and treat it aggressively with doxycycline given
at a high dose for a longer period of time than the Merck
Veterinary Manual recommends.
All that being said, it is almost a necessity for the dog owner to
learn as much as he/she can about Ehrlichiosis and the other forms of TBD,
or at least be aware that dogs could become infected and be
ready to insist that he be tested and treated aggressively if tick disease is
found.
RESOURCES
Some excellent sources of information about
Ehrlichiosis and other TBDs, given in much more depth, can be
found at the links below.
Ehrlichiosis: A Silent and Deadly Killer
www.srv.net/~cdm/Dale/ehrlichia.html
Ehrlichosis: e-medicine.com
www.emedicine.com/ped/topic655.htm
Newsday.com: Interview with Susan Netboy and
Dr. Ibulaimu Kakoma
http://makeashorterlink.com/?M296521B5
Critter Fixer Pet Hospital: ehrlichiosis
www.critterfixer.com/pages/petcare_ehrlichiosis.asp
Journal of Clinical Microbiology
http://jcm.asm.org/cgi/content/full/36/7/2140
Tick Borne Ehrlichiae and Rickettsiae of Dogs -
updated may 2003
www.ivis.org
Document No. A0315.0503. Recent Advances in
Canine Infectious
Diseases: Canine Monocytic Erhlichiosis
www.ivis.org/advances/Infect_Dis_Carmichael/waner/chapter_frm.aspImizol
product label
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By Gil Ash
Proud Owner of a Black, American Bred German
Shepherd Dog
Bauernhoffen's Rain Dragon: Traveler
http://nowhereelse.homestead.com/Thunder.html
A strong Immune System Actually helps to repel
parasites and insects!
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a Stronger and more Efficient immune system
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