Ehrlichia

During this past year, Winstar Nightwatch Kennel was struck with the death of two of its best dogs, Sophie and Jlo.

Sophie was our evidence tracking and narcotics dog. She suddenly stopped eating, became weak, stopped urinating and died. Jlo was the bitch for our second litter. From her we obtained fabulous dogs such as Bolo, B-Lee and Bronx. These are currently all working dogs in area protection and narcotics. Jlo developed severe swelling of her hind legs, progressively lost weight and ultimately had to be put down. Both dogs deteriorated despite appropriate medical treatment and died of complications secondary to Ehrlichia. Despite regular and consistent cleaning, disinfecting and pest control, our Kennel was affected by this potentially deadly disease. Let’s talk about these bacteria, what it is, how it infects, treatment and eradication efforts. Ehrlichia are a type of bacteria that infect and live within the white blood cells of their hosts. Different types of Ehrlichia live in different types of white blood cells. The hosts can be human, pet, or wild animals. They are spread from host to host by tick bites and their location inside the cell makes them difficult to kill since most antibiotics do not go into the inside of cells.

Recent molecular biology has allowed renaming and reclassification of Ehrlichia.

• Ehrlichia canis ( dog infection)
• Ehrlichia lewinii ( dog infection)
• Ehrlichia chaffeensis ( human infection)
• Ehrlichia ruminantium
• Anaplasma phagocytophilia and platys

The scope of the illness created by Ehrlichia infected dogs became evident during the Viet Nam was as the military German Shepherd dogs became ill with an infection that wiped out their blood cells. Because both the red and white blood cells were affected, it was called Tropical Pancytopenia. It was soon realized that these were also found in the US. Once they found that humans could be infected they began intensive research.

Different Ehrlichia species are spread by different types of ticks. According to the tick available in a particular area limits the type of infection. The Brown Dog Tick spreads Ehrlichia canis, lewinii and other diseases. It is available in warmer climates despite the fact that it can survive as long as it is inside.

There are three phases of illness with Ehrlichiosis.

• Acute Phase: This is generally a mild phase and occurs 1 to 3 weeks after the dog is bitten by the tick. The organism is replicated in this time period and attaches to the white blood cell membrane. The platelet count drops and destruction occurs. The dog will be listless, does not eat and may have enlarged lymph nodes.
• Subclinical Phase: In this phase the dog appears normal. The organism has taken over the spleen and is hiding out there. The dog can stay in this phase for months or years. A blood test in this phase may reveal slightly decrease platelets and elevated globulins.
• Chronic Phase: In this phase the dog gets sick again. Up to 60% of dogs infected with Ehrlichia canis will have abnormal bleeding due to the decreased platelets. Inflammation in the eyes, neurological effects, and kidney infections (glomerulonephritis) with serious protein loss. Infections with Ehrlichia lewinii will also produce arthritis in addition to the other signs and symptoms that were mentioned.

The diagnosis is made by a series of tests. First are the typical findings:

• A dog with fever, enlarged lymph nodes, bleeding, or arthritis in multiple joints.
• Low platelet numbers, high globulin levels and mild anemia on blood tests.

A blood test for antibodies against Ehrlichia organisms is ordered. A positive test indicates that the dog has been exposed to Ehrlichia but does not imply active current infection necessarily. The IFA (immunofluorescent antibody) and ELISA (enzyme-linked immunosorbent assay) are the two tests that can be performed. The IFA is the traditional on and can be positive 7 to 28 days after the dog has become infected. The ELISA test is included in a new in-house test kit that also includes a Lyme disease test and a heartworm test. A PCR test for the presence of Ehrlichia organisms has recently become available. It is currently recommended that a combination of a PCR test and antibody titers be performed.

Tetracycline is probably the most effective antibiotic against Ehrlichia. Doxycycline has a more convenient dosing scheduling. At least a month of treatment will be needed. The response is initially rapid. If immune-mediated arthritis or platelet loss is a problem, corticosteroids such as prednisone can be used. After infection, it is possible to become reinfected. There is no lasting immunity to Ehrlichia.