Ehrlichiosis, one of several diseases from ticks your puppy can get, goes by many names. It's also called tropical canine pancytopenia, canine typhus, canine hemorrhagic fever, Nairobi bleeding disease, and tracker dog disease. Canine ehrlichiosis is caused by Ehrlichia canis (E. canis) a kind of specialized bacteria that requires an intermediate host, or vector, to infect its victim. The brown dog tick (Rhipicephalus sanguineus) is the primary vector.
The disease has been reported worldwide wherever the brown dog tick is found. Most cases in the United States occur in dogs living in the Texas Gulf coast regions and other southern states. All dogs are susceptible, but those with greater exposure to ticks -- outdoor dogs, working dogs and hunting dogs -- are at highest risk. Ehrlichiosis is diagnosed most often during the warm months of tick season.
How Ehrlichiosis is Transmitted
The tick becomes infected when it bites an exposed dog and ingests infected blood. The tick may transmit the disease for up to five months after engorgement with infected blood. Once infected, transmission of the disease to dogs can occur in any stage (by larva, nymph, or adult tick). It is even possible for ticks to survive winter months and infect susceptible dogs in the spring.
The organism is passed to dogs in the tick saliva when the infected parasite takes a blood meal. Blood transfusion from an infected donor dog also has the potential to transmit the disease. E. canis initially invades and damages the white blood cells of the host dog. From there, the rickettsiae spread via the blood to lymphatic tissue including the liver, lymph nodes and spleen.
Symptoms To Watch For
Signs of the disease can vary greatly from case to case, making canine ehrlichiosis an extremely frustrating disease to diagnose. German Shepherd Dogs appear to be much more sensitive than other dogs. Dogs suffering stress are also more susceptible.
There are both acute and chronic stages of the disease. Dogs suffering from the acute phase exhibit sudden severe symptoms, or show few or no signs at all. Signs include a week-long fever, eye and nasal discharge, loss of appetite, depression, swollen legs, stiffness and reluctance to walk, and weight loss, and some dogs show neurologic symptoms such as muscle twitches. X-rays may reveal signs of pneumonia. The acute stage lasts two to four weeks; dogs either recover, or proceed to the chronic phase of disease.
The chronic stage of the disease can last for several months, and appears to affect dogs with suppressed immune systems. The bone marrow is compromised, resulting in a reduction in the production of blood cells. Often, the dog will develop kidney disease. Low platelet counts may cause bleeding tendencies, and long nosed breeds like shepherds may suffer nose bleeds. Fatigue, bloody urine, discoloration and bruising of the skin occur in all breeds.
How Is Ehrlichiosis Diagnosed
Diagnosis is based on signs of disease along with history of tick exposure; laboratory tests of the blood that find the organism will confirm the diagnosis. The antibiotic tetracycline is effective against E. canis when administered early in the course of the disease. Dogs may require six weeks or more of treatment before being cured, and some may benefit from fluid therapy or blood transfusions.
Recovered pups tend to be immune to subsequent infection or develop only mild disease. However, dogs with chronic disease in which bone marrow is irreparably damaged may require months of therapy before any improvement is apparent, but prognosis is not good and often the dog dies despite treatment.
There is no vaccination available to prevent canine ehrlichiosis. The best way to protect your puppy is to reduce or prevent his exposure to ticks. In high-risk environments (i.e., kennel situations where the disease has been diagnosed), a daily low-dose of tetracycline may be used as a preventative.