Many of our clients have had questions concerning tick borne diseases
recently. I felt that it would be helpful to write a small article on the
most common tick disease that we see in our practice.
Please e mail me at priestlake@mindspring.com if you would like to see
other topics covered in
future emails.
Sincerely,
Dr. Pennington
EHRLICHIOSIS
Erlichiosis is a disease caused by bacteria, Ehrlichia, that infect white
blood cells and are transmitted by the bite of an infected tick.
The lone star tick, the American dog tick (or wood tick) and the deer
tick (or black-legged tick) have been associated with ehrlichiosis. A
tick can survive for 6 years with no nourishment other than water from the air.
The tick *can* transmit disease regardless of the length of attachment
*if* it regurgitates stomach contents into the host's bloodstream. Often,
this occurs when a tick is improperly removed (i.e., by compressing its
body, rather than by using a tick remover or tweezers as close as possible
to the mouth.)
The ticks, often no bigger than a pin head, become active and can spread
disease any time of the year when the temperature is 40 degrees or more at
ground level. Peak months for tick-borne diseases are June and July.
What are the symptoms of ehrlichiosis in humans?
Illness due to ehrlichiosis can be so mild that no medical care is sought
or the illness can be severe and sometimes fatal. Symptoms are generally
non-specific and other diagnoses may be considered. The more common
complaints are fever, headache and muscle aches. Persons with ehrlichiosis
also may experience loss of appetite, nausea and vomiting. A rash can
occur but is usually not present.
What are the symptoms of ehrlichiosis in pets?
The disease typically courses through three stages. The first is the early
or acute stage (which usually mimics a mild viral infection.) The signs in
this stage may be very subtle and could go unnoticed. Without proper
treatment the animal will go on to a subclinical (second) stage or may
advance to the chronic (final) stage. During the acute stage most, if not
all, damage is reversible and a full recovery is possible. It is during
this stage that treatment is most effective, which emphasizes the need for
early detection.
Once the chronic stage is reached, the rickettsial organism has taken up
residence within the bone marrow. At this point the damage done is often
irreversible. It is not unusual for dogs in this final stage to suffer
massive internal hemorrhage, or succumb to sudden stroke, heart attack,
renal failure, splenic rupture or liver failure, resulting in death. A
peculiarity about the disease is these dogs often do not look or act as
though they are in a terminal stage of disease until their final hour.
DETECTION OF EHRLICHIA
If there is any one element of this disease that makes it especially
deadly, it is the ability it possesses to mimic other diseases. Perhaps
the best description of ehrlichiosis is "the AIDS of the canine world".
The detection of the disease has, so far, only been successfully
accomplished through IFA (indirect fluorescent antibody test) which
detects the presence of antibodies.
Regardless of the what the titer is, any positive should be considered
indicative of infection and treated quickly and aggressively. A dog with a
negative titer who has signs should still be treated, then re-tested at a
later date.
Additionally, the severe depression of the immune system created by the
disease opens the door to secondary bacterial infections and other
complications. Because the onset of visible signs is likely to be gradual
in the chronic phase and subtle in appearance, alertness to the following
conditions is imperative in order to catch the disease while it is still
treatable:
1.weakness
2.cough
3.labored breathing
4.fatigue
5.pneumonia
6.intermittent fever
7.arthritis
8.muscle wasting
9.discharge from nose or eye
10.depression
TREATMENT OF EHRLICHIOSIS
Due to the rapid spread and inadequate publicity the single biggest
failure has been the failure to recognize and test for the disease.
Perhaps the strongest recommendation that can be made is to eliminate
ehrlichiosis first as a possible cause by treating with appropriate
antibiotics to see if the animal responds. If an animal has any of the
above signs an excellent path would be to take blood for a Indirect
Fluorescent Antibody (IFA) test and start the animal on doxycycline
immediately.
If Lyme disease is the suspect then we treat with doxycycline. Although
some chronically-infected dogs may need steroid treatment, this should
always be done in conjunction with doxycycline treatment and only as a
last resort measure.
How can ehrlichiosis be prevented in people and their pets?
Persons spending time outdoors in tick-infested areas should take
precautions against all tick borne diseases:
Wear light-colored clothing so ticks are easier to see. Wear long-sleeved
shirts, long pants, socks and closed shoes (rather than sandals). Tuck
shirts into pants and pant cuffs into the tops of socks.
Walk in the center of paths, trails, or cleared or mowed areas to avoid
brushing against vegetation. While in potential tick habitats, check
yourself and companions every few hours and promptly remove any
tick(s). Repellents also can be applied to discourage ticks from
attaching to skin or clothing. Repellents containing up to 30 percent DEET
have been shown to be effective in repelling ticks. Use these products
cautiously on children and supervise application. Repellents containing
permethrin can be sprayed on clothing. Regardless of the type of
repellent used, be sure to follow the manufacturer's directions. Do not
overuse or misuse repellents. If possible, avoid areas known to be tick
infested.
Pets should be protected with a preventic collar or frontline topical or
spray (spray provides better barrier protection) when they will be in
areas that are tick infested.
How should an attached tick be removed?
Grasp the tick as close to the skin's surface as possible with tweezers
and pull straight back in a slow, steady motion without twisting. Avoid
crushing the tick's body because it may contain infectious fluid. If you
do not have tweezers, you can use your fingertips but they should be
covered (with tissue paper or gloves). After the tick is removed, wash the
bite site and your hands with soap and water and apply a disinfectant or
antibiotic ointment to the site.
