In the paragraphs that follow, we will explain the tick-borne diseases
found in our region: Lyme Disease and
Ehrlichiosis. We will briefly cover the
symptoms, diagnosis, and treatment of these diseases. In addition, we
have a section on Preventing Tick
Infestation at the end.
This page is meant only to serve as an introduction to these diseases. If
you have specific questions or concerns about your pet, please contact us
at 218-525-1937 for further information.
General Tick Information
Ticks are commonly found in Minnesota and Wisconsin.
There are two main types of ticks common to this region: Deer Ticks and
Brown Dog Ticks (sometimes known as Wood Ticks). They're most abundant in
the spring, summer, and fall. They live in low bushes and tall grass,
where, as your pet passes through, they can come in contact with their (or
your) skin. (Ticks don't jump, fly or dive off trees, as is commonly
believed.)
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Deer Tick
(Ixodes) |
Dog Tick
(Dermacentor) |
Lyme disease is one of the most common tick-transmitted
diseases in the world, caused by the spirochete Borrelia burgdorferi.
While Lyme disease has been reported in cats, it is primarily a disease of
dogs (and people). Lyme disease in people is also caused by ticks -
infected dogs cannot spread the disease directly to people.
Transmission
The spirochete, Borrelia burgdorferi., is transmitted by
the deer (Ixodes) tick. Infection takes place after the tick is partially
engorged, 24-48 hours after the initial attachment. Infection is
generally transmitted by the nymphal stage of the tick in the spring and
the adult female tick in the fall. Ixodes ticks have a 2 year life
cycle. Larvae hatch in spring and become infected by feeding on
white-footed mice, which are persistently infected. The larvae molt into
nymphs in the spring of the following year and stay infected or become
infected by feeding on mice. Nymphs molt into adults in late fall of the
second year. Adult female ticks engorge after mating on deer or other
mammals, fall off, and hid under leaves until the following spring when
they lay eggs. Adult male ticks tend to stay on the deer. Once a dog
has been infected, the incubation period prior to clinical disease is
thought to be 2-5 months.
Clinical Signs
The dominant clinical feature in dogs is recurrent acute
arthritis with lameness, sometimes with fever, anorexia, and depression.
During the acute lameness, one or more joints may be swollen and warm and
may be painful when manipulated. Dogs may walk stiffly with an arched
back and may be sensitive to touch. Lameness generally lasts for only 3-4
days. Interestingly, only about 5% of dogs who have been exposed to
Borrelia actually develop clinical disease.
Diagnosis
Diagnosis is based on clinical signs, response to therapy,
and blood tests for the presence of antibodies to Borrelia. However,
classic antibody tests (ELISA) cannot distinguish between antibodies
resulting from natural infection and those resulting from vaccination.
There is a more specific test, called a western blot protein
electrophoresis which can more accurately distinguish the different types
of antibodies. However, positive results only indicate a previous
exposure to Borrelia and must be combined with clinical signs and
interpretation to be diagnostic of Lyme disease.
Treatment
Treatment consists primarily of antibiotic therapy. The
most commonly prescribed antibiotics for Lyme disease are doxycycline and
amoxicillin. The duration of treatment is somewhat controversial, but
generally a treatment of 2-4 weeks is recommended. Restricted activity is
often recommended until the lameness resolves. Improvement is generally
quite rapid, occurring in the first few days of treatment.
Prevention
Prevention against Lyme disease is best obtained by
avoiding tick infestation and by vaccinating. Lyme vaccination has been
found to be quite effective in dogs that have not been previously exposed
to Lyme disease, so beginning the vaccinations in young dogs is
advisable. Dogs which are seropositive (have previously been exposed)
will obtain some degree of protection against future Lyme infection, but
vaccine failure is more likely in these dogs.
Because of the risk of other disease (ehrlichia) and the potential to
bring ticks into contact with humans, it is also strongly advisable to
prevent tick infestation, even in dogs who are vaccinated against Lyme
disease. See the section below - preventing tick infestation.
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Ehrlichiosis is a tick-borne rickettsial disease which has
been recognized more frequently in our region in recent years.
Ehrlichiosis occurs in dogs and cats and can also occur in people Like
Lyme Disease, Ehrlichia in people is caused by a tick - you cannot get it
from your pet.
Transmission
Ticks transmit Ehrlichia in their saliva. Both deer ticks
and dog ticks have been implicated as carriers of Ehrlichia. Clinical
disease can occur after a 1-3 week incubation period. Ehrlichiosis can
occur at any time of the year.
Clinical Signs
The signs of Ehrlichiosis are more subtle than those of
Lyme disease. For this reason, many animals are infected months prior to
seeking medical attention. Typical signs include lethargy, depression,
anorexia, weight loss, fever, bleeding tendencies, labored breathing and
often enlarged lymph nodes. Diagnosis is made through clinical
assessment, bloodwork (numerous changes found in a complete blood count)
and by obtaining Ehrlichia blood titers.
Treatment
Prognosis is excellent in acute cases. Chronic cases may
take over a month of treatment to clear and those in which the bone marrow
is not responding correctly have a poor prognosis. Therefore, early
recognition and treatment affords the best opportunity for a successful
outcome. The primary treatment is with the antibiotic doxycycline. In
addition, glucocorticoids may be indicated in acute cases with serious
blood disorders. Supportive care must also be given, including fluid
support and blood transfusion when necessary. Frequent monitoring of
blood during therapy is crucial.
Prevention
There is no vaccine against Ehrlichia. Therefore,
prevention is obtained exclusively through preventing tick infestation.
(see below)
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There are numerous flea and tick
products available in the marketplace today. How do you choose the best
product for your pet? We have seen many new products in the past few
years and with national advertising campaigns, most of the products are
gaining name-recognition. However, they are not all as effective as the
advertising would lead you to believe.
It is important to remember that
not all flea products protect against ticks. Many of the
prominently advertised preventives protect against fleas only. Examples
include Program®, Advantage®, and Sentinel®. Make sure that the product
you choose is effective against fleas and ticks. Cat owners should be
particularly careful, because most tick preventives used in dogs are not
safe for cats.
The tick preventive we believe works
best is Frontline® Top Spot which protects against fleas
and ticks and available for dogs and cats. It combines a high safety
margin with an effective flea and tick kill. Frontline® is a "spot-on"
product which covers the entire body by spreading in the natural oils of
the skin. It effectively repels water and will remain effective even if
your pet likes to spend time in the water.
Frontline® is fully guaranteed - if
you are not completely satisfied for any reason, we will replace it or
refund your purchase price.
