Tick-borne Viruses in Dogs
Four tick-borne diseases commonly affect dogs: babesiosis, Lyme disease, Ehrlichiosis and Rocky Mountain spotted fever. A bacteria causes Lyme disease and a parasite infestation at the time of a tick bite causes babesiosis. Only Ehrlichiosis and Rocky Mountain spotted fever result from a rickettsial organisms that contain both the characteristics of bacteria and a virus, according to Glendale Animal Hospital. Once within the body, they act like a parasite. Both conditions may prove fatal without immediate veterinary treatment.
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Transmission
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The transmission of Ehrlichiosis occurs when a tick bites an infected dog, ingesting a bit of blood. The tick then goes on to bite another dog and transmits the organism known as the rickettsial, Ehrlichia canis. Both the Dermatocentor variabilis (American dog tick) and Dermatocentor andersoni (Rocky Mountain wood tick) transmit the Rocky Mountain spotted fever. In order to transmit the virus, the tick must remain attached to the host dog for five to 20 hours. Transmission of Lyme disease (borreliosis) bacteria occurs when the common deer tick (Ixodes scapularis) remains attached to the dog for at least 48 hours. Transmission of the parasite babesiosis requires that the tick be attached to the dog for at least 48 to 72 hours.
Spread in Body
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Ehrlichiosis enters the dog's blood stream but does not cause symptoms until at least eight to 20 days have passed. A chronic form of the virus can also manifest itself but may not exhibit symptoms for months or even years after transmission occurs. Rocky Mountain spotted fever enters the blood stream from the tick's mouth and makes its way into the lymph nodes system of the canine. From there it spreads to all organs of the body. Symptoms begin two to three days after the tick bite. Symptoms of Lyme disease manifest within five months. Babesiosis causes symptoms 20 days after infestation.
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Symptoms
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Dogs infected with Ehrlichiosis may exhibit loss of appetite, fever and malaise. Many times, years will pass before the dog begins to exhibit anemia, weight loss, organ dysfunction, organ failure and excessive bleeding of organs which can lead to death. Dogs suffering from Rocky Mountain spotted fever begin to run an excessively high fever, often topping 104 degrees F, according to Pet Place. The dog may suffer from lack of appetite, swollen joints, a stiff gait and depression. Coughing, vomiting, nosebleeds and diarrhea often occur. The eyes may also be involved and appear swollen. The first symptom of Lyme disease is a high fever of 105 degrees F or more. Babesiosis begins to affect the liver with the symptoms of jaundice developing.
Diagnosis
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The veterinarian will examine the dog and take its health history. Bloodwork will normally be ordered. Complete blood count (CBC) will reveal Ehrlichiosis, Lyme disease, babesiosis and Spotted Rocky Mountain spotted fever. An increase in liver enzymes is normally exhibited in infected dogs. White blood cell count will help diagnosis the virus. Kidney insufficiency is also common. The blood will also undergo an indirect fluorescent antibody (IFA) test to determine the presence of a virus.
Treatment
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Ehrlichiosis responds well to antibiotics in the tetracycline family. Enrofloxacin is also being utilized in the treatment of the virus, according to IDEXX VetConnect. Dogs suffering from Rocky Mountain spotted fever will normally require hospitalization and the intravenous administration of fluids. Doxycycline, chloramphenicol or oxytetracycline treat both Rocky Mountain spotted fever and Lyme disease. Babesiosis is rarely treated due to the severe side effects and it is virtually impossible to rid the body of the parasite. The dog's immune system normally kicks in and allows the dog to live a relatively normal life.
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References
Resources
- Photo Credit labrador dog image by muro from Fotolia.com
