Ehrlichiosis (Tick fever) in dogs

Canine Ehrlichiosis, commonly known as “tick fever,” is caused by a germ (rickettsia) called ehrlichia canis. Ehrlichia is named in honour of Dr Ehrlich, who first described the germ.{{more}}

The organism is partly like a bacteria and partly like a virus and acts as a parasite of the body’s blood cells and organs. Dogs get tick fever from tick bites. Ehrlichia are spread from host to host by tick bites and their intracellular location makes them difficult to remove as most antibiotics do not penetrate to the inside of cells. It is also possible for dogs to become infected through a blood transfusion from an infected dog.

This disease is quite prevalent in St Vincent and the Grenadines in the dog population and dogs of any age are susceptible to the disease if they are exposed to tick bites.

How does the disease progress?

The dog is first infected by a tick bite or faulty blood transfusion that is done without adequately testing the donor dog for tick fever.

The germ (ehrlichia canis) enters the blood stream and during the next seven to 21 days, multiplies mainly in the lymph nodes, spleen, liver, and bone marrow, causing the spleen, liver and lymph nodes to enlarge.

The germ then causes the destruction of the platelets in the blood. As most of you know, without platelets, the blood does not clot effectively. This in turn causes the excess bleeding seen in dogs with tick fever.

How do I suspect that my dog has tick fever?

This disease comes in various different forms. There may be a wide variety of symptoms. Some of these that I see most often are:

1. The dog appears to be pale (anemic); this is mostly observed in the gums, tongue, the inner part of the lower eyelids etc.

2. Because of the anemia, the blood gets thin and fluids could seep into the scrotal sac and into the tissues of the legs, or abdomen, causing one or more to be swollen.

3. The animal could have a persistent fever.

4. The animal does not want to eat much or there is no appetite at all.

5. The lymph nodes below the jaw appear to be swollen when palpated.

6. The animal could develop a limp for no apparent reason due to bleeding in the joints.

7. The dog may lose weight and appear to be sluggish.

8. There could be blood in the stool, due to bleeding in the guts.

9. There could appear little blotches of blood under the skin, especially seen in the ventral abdominal areas of the inner portion of the ear flap, caused by bleeding under the skin.

10. I have observed bleeding in the eyes and or uveitis ( inflammation of the middle layer of the eye)

11. I have observed neurological signs (seizures etc) in some cases, caused by meningoencephalitis, especially in German shepherds.

Diagnosis:

Diagnosis of this disease is relatively simple. A small amount of blood is taken from the animal and a blood test is done; this takes only about 10 minutes. If the dog is affected, the platelets are found to be low.

Other serological tests could also be performed to determine antibody titres.

Treatment:

The prognosis for recovery in cases of tick fever, if diagnosed correctly, is good, except in cases where the dog is showing neurological signs or when the disease has progressed to the point where there are multiple organ failures.

In severe cases, the dog may require a blood transfusion.

Prevention:

Tick control is the most effective way of prevention.

From my experience, once the dog is infected by tick fever, 90 per cent of the times, re-infection occurs. It is therefore advisable that a blood test is done at least every six months on the dog to monitor its health.

For further information, contact: Dr Collin Boyle
Unique Animal Care Co. Ltd.
Tel: 456 4981
Website: www.uniqueanimalcare.com