Ehrlichiosis in Dogs

In the 1970’s ehrlichiosis was first recognized as a significant and serious illness; due to the infection and death of many military dogs returning home from the Vietnam War. 

Also known as canine hemorrhagic fever, this condition can cause lethargy, breathing problems, and ocular discharge. Other names for this condition are canine typhus, tracker dog disease, canine rickettsiosis, and tropical canine pancytopenia.

Ehrlichiosis is an infectious tick-borne illness caused by Ehrlichia, a bacteria belonging to the family Ehrlichiaceae. The bacteria attacks the canine’s blood cells, progressing into a chronic infection.

The symptoms of ehrlichiosis can vary from mild to severe. You may notice one or more of the following symptoms:

• Ticks found attached to your pet
• Fever
• Lethargy
• Weakness
• Weight loss
• Difficulty breathing
• Sneezing
• Anemia
• Discharge coming from the eyes
• Lack of appetite
• Nasal discharge
• Joint pain
• Swelling of the legs
• Nose bleeds
• Loss of coordination
• Swollen lymph nodes
• Edema (retention of fluids under the skin)
• Bleeding inside the eye
• Blindness

Types

The acute stage occurs early in the disease, several weeks after the canine was infected.  During this stage the infected dog may have a fever, respiratory distress, swollen lymph nodes, weight loss and bone marrow suppression. This stage may last a month.

The sub-clinical stage has no outward symptoms even though the organisms are still present.  The dog’s immune system may be able to eliminate the disease during this stage.

The chronic stage is the most serious stage of the infection and can be fatal.  During this stage the canine will have a low platelet count and may experience, lameness, low blood count, nose or eye bleeding, and kidney disease.  The bacteria may also spread into the organ tissues, especially those of the spleen, liver, lung and lymph nodes.

• The most common cause of ehrlichiosis is the bacteria Ehrlichia canis which is transmitted to the canine through the saliva of the brown tick
• Brown ticks can be found in southwestern and Gulf Coast regions of the USA
• The Anaplasma bacteria can also cause ehrlichiosis, transmitted by the saliva of hard shelled ixodes ticks
• Ixodes ticks can be found in California, Midwestern and Northeastern states
• Ehrlichia chaffeensis are transmitted by the saliva of the lone star tick 
• Lone star ticks can be found throughout the Eastern, Southeastern and Southcentral states
• It is also possible for dogs to become infected through a blood transfusion from a dog that has ehrlichiosis

Your veterinarian will take a thorough medical history of your pet. He will ask questions regarding the existing health concerns and when the onset of the symptoms started. Your veterinarian will then perform a physical exam. 

The veterinarian team will most likely recommend bloodwork. A complete blood count test (CBC) usually will show a decreased number of platelets and low red and white cells in pets infected with ehrlichia.  An ELISA test will check your pet’s serum (blood that has been allowed to clot then spun down in a centrifuge) to detect antibodies to ehrlichia bacteria. Another diagnostic test that may be recommended is the polymerase chain reaction (PCR) test.  This test helps identify specific genes unique to ehrlichiosis.

To help your pet with his current symptoms your veterinarian may prescribe antibiotics before all of the results of the blood test return. The sooner the treatment for tick-borne disease starts, the better.

Dogs that have severe anemia or are experiencing bleeding problems may need to be kept overnight for observation and possibly require a blood transfusion. If your dog is dehydrated, he may need to be given intravenous fluids that contain electrolytes. 

Antibiotics such as doxycycline, tetracycline, minocycline, or oxytetracycline are all very effective treatment against ehrlichiosis.  Treatment may last up to six weeks to ensure a full recovery. If your pet’s bone marrow was compromised he may be prescribed androgen steroids to help stimulate bone marrow production. Curious about which health plan is right for your dog? Head over to Forbes' breakdown of the best pet insurance.

Follow-up visits will be needed to re-run bloodwork and check on your pet’s progress. Prognosis for canines with acute ehrlichiosis is very good if the treatment plan is followed. Dogs with subclinical ehrlichiosis may remain in this phase with no symptoms for their life time. In the case of chronic ehrlichiosis, it may take longer for your pet to fully recover.

To prevent ehrlichiosis from recurring, your veterinarian can suggest tick preventatives for your dog such as dips, sprays or monthly topical. It should be noted that humans can also become infected with this disease as the result of a tick bite.