The Disease and it's Transmission
Ehrlichiosis, tick fever, a disease seen across the continental U.S., occurs with the most frequency in the southern states including Arizona. Since other systemic signs of this disease are often vague and mild in the early stages, ocular changes may be the first indication to test for Ehrlichiosis. Ocular manifestations include uveitis, retinal disease, and corneal opacities. Early detection, diagnosis, and treatment greatly increase chances for saving vision and even the life of the pet.

Rhipicephalus Sanguinus, the common brown dog tick, transmits Ehrlichiosis to dogs. Direct contact between a healthy dog and an infected dog will not spread the disease. Canine Ehrlichiosis does not cause disease in humans. Ticks may not always be present when the first signs of disease appear because of the long incubation period of eight to twenty days. Ehrlichiosis may appear at any time during the year, not just tick season, due to the chronic nature of the disease, and because of this tick's ability to survive indoors throughout the year.

Diagnosis
History and clinical signs may be suggestive of Ehrlichiosis, while general blood tests may increase suspicion. Ehrlichiosis commonly causes changes in blood screening tests. Once suspected, Ehrlichiosis can be diagnosed by sending a blood sample to a laboratory for specific testing. Diagnosis is important for treatment and prevention.

Symptoms
Symptoms of Ehrlichiosis are often diverse and vague and can vary during the three different phases of the disease. The first phase, called the acute phase, occurs eight to twenty days following exposure. During this phase, mild signs including fever, nasal discharge, anorexia, lymph node enlargement, and breathing difficulty occur. Unfortunately, these signs are not specific for Ehrlichiosis. After one to two weeks the pet recovers. The next phase, the subclinical phase, shows no signs and lasts one to four months. During this time, the pet may mount a sufficient immune response to rid itself of the disease. If not, the chronic phase begins. Signs during this phase can be severe and include depression, weight loss, abdominal tenderness, and bleeding tendencies such as coughing up blood. This phase generally continues until a diagnosis can be made and treatment begins.

Treatment
Treatment of Ehrlichiosis depends on the severity of the disease at the time of detection. In severe cases, immediate supportive care may include blood transfusions and fluid administration. To treat ocular diseases associated with Ehrlichiosis, therapy may include corticosteroids. The Ehrlichiosis organism is susceptible to many different antibiotics. The current antibiotic of choice is tetracycline or one of its derivatives. This type of antibiotic is quickly effective in most cases. If a relapse occurs, a different antibiotic may be chosen. German Shepherds are more sensitive to this disease and may require more rigorous and long term therapy. Once treatment ceases, prevention is important to lower the chances of reinfection.

Prevention
Unfortunately, no effective vaccine exists to prevent Ehrlichiosis. However, due to the life cycle of the brown dog tick, other methods of prevention can be employed. Unlike other ticks which feed on many different kinds of hosts, the brown dog tick feeds only on dogs and survives mainly in areas where dogs live. This facilitates effective tick control. After treatment of Ehrlichiosis, no lasting immunity develops. Tick control is often the best method to prevent reinfection. Infected ticks may transmit the disease for five months or longer. Therefore, tick control in the environment and on the dog should be maintained on a regular basis.

Prognosis
Tick fever can be a chronic, debilitating, and even fatal disease if not treated. However, successful treatment of Ehrlichiosis is common if the disease is detected early. Ocular disease may provide the first clue in the diagnosis of Ehrlichiosis. Most ocular diseases associated with Ehrlichiosis require aggressive and prompt therapy to prevent permanent damage. Once treatment is finished, prevention by control of the tick population will help to decrease the chance of reinfection so your pet can continue to lead a normal life.

If you have any questions about Ehrlichiosis - Tick Fever, please do not hesitate to call us at Eye Care for Animals.