Babesiosis in Dogs
Overview of Canine Babesiosis
Canine babesiosis is a tick-borne disease caused by a protozoan blood parasite. The cause of the disease is an organism of the genus Babesia. There are two species of Babesia that can cause disease in the United States: Babesia canis and Babesia gibsoni.
The organism is spread to dogs through the bite of a tick and can infect dogs of all ages, although most infected dogs are less than three years old. In the United States, there is a peak incidence occurring between March and October. Greyhounds have a higher incidence of the disease than other breeds.
Babesiosis mainly affects red blood cells, causing anemia, although many organ systems can be involved, and many complications can arise; disease can be mild, or can be fatal.
What to Watch For
Symptoms of babesiosis in dogs may include:
- Pale gums
- Labored breathing
- Failure to produce urine
- Excessive thirst
- Hemoglobinuria (red colored urine)
- Jaundice that appears as a yellow coloration of the gums and whites of the eyes
- Severe respiratory distress
- Fast breathing
- Blood tinged frothy nasal discharge
Diagnosis of Babesiosis in Dogs
- Complete blood count, chemistry panel and urinalysis
- Evaluation of a blood smear
Treatment of Babesiosis in Dogs
- Diminazene aceturate
- Trypan blue
- Blood transfusions
- Supportive care
Home Care and Prevention
Administer medication as prescribed. Since the disease is spread by ticks, preventing tick exposure is paramount.
In-depth Information on Babesia Infection in Dogs
Canine babesiosis is a tick-borne disease caused by the protozoan blood parasite Babesia. Although primarily a red blood cell parasite, Babesia can affect multiple organs. Hemolytic anemia, whereby the red blood cells are destroyed, is the hallmark of Babesia infection, many variations and complications can occur.
The organism that causes babesiosis is either Babesia canis or Babesia gibsoni. There are three subspecies of Babesia canis. One subspecies is found in Europe, another in northern Africa and North America, and the third in southern Africa. Babesia canis is pear-shaped and is usually infects red blood cells in pairs. Babesia gibsoni is round or oval, and is smaller than Babesia canis. It is found in Asia, North America, and eastern Africa.
Babesiosis is transmitted by ticks. A tick will feed on a dog that is sick or incubating the disease, and then feed on a susceptible dog. The incubation period following the tick bite is 10 to 21 days. Dogs of all ages can be infected, although it tends to be seen in dogs younger than three years of age. Other canids, such as wild dogs, jackals, and wolves are also susceptible. A seasonal variation in the number of cases diagnosed has been described in North America, with most cases occurring between March and October. In the southeastern United States, greyhounds have a higher prevalence than that of the general pet population.
The Babesia organism infects red blood cells. This causes hemolysis, which is destruction of the red blood cell. Fever and enlargement of the spleen may occur. Although the parasite infected red blood cells, it triggers an excessive inflammatory response that may cause widespread inflammation and multi-organ damage. The kidneys may be affected, and acute kidney failure may occur. The parasitized red blood cells may cause sludging in the small vessels in the brain, resulting in neurologic signs such as seizures, semi-coma, or coma. The excessive, unchecked inflammatory response that occurs throughout the body may affect the lungs, causing a serious condition called acute respiratory distress syndrome in which dogs show severe life-threatening respiratory compromise.
Canine babesiosis is often classified as uncomplicated or complicated. Uncomplicated babesiosis tends to have signs relating to anemia only, such as fever, anorexia, depression, pale gums, enlarged spleen, and bounding pulses. Uncomplicated babesiosis is further subdivided into mild, moderate, or severe, depending on the severity of the anemia. Mild uncomplicated cases may progress to severe uncomplicated disease, whereby the anemia becomes life threatening. Complicated babesiosis involves clinical manifestations that are unrelated to anemia.
Common Complications of Babesiosis in Dogs
- Acute kidney failure
- Cerebral babesiosis (neurologic signs are the most evident)
- Coagulopathy (blood clotting disorders)
- Jaundice (yellow discoloration of the mucous membranes)
- Liver damage
- Acute respiratory distress syndrome
Acute kidney failure is an uncommon complication. Dogs with babesiosis and acute kidney failure will have abnormally elevated kidney values on their serum chemistry panels, and will have many abnormalities on their urinalysis. Most dogs will produce less urine than normal, and some will have total kidney shutdown and will not produce any urine at all.
Cerebral babesiosis involves the brain and is characterized by neurologic signs such as incoordination, partial paralysis of the hind legs, muscle tremors, different sized pupils, intermittent loss of consciousness, seizures, stupor, or coma. Fortunately, survivors of cerebral babesiosis often have no long-term neurologic deficits.
The most consistent abnormality on a complete blood count is a low platelet count, however, clinically apparent hemorrhage is rare.
In advanced cases of babesiosis, jaundice can occur. Jaundice is often seen in dogs that have anemia caused by destruction of their red blood cells, however, jaundice may also be due to liver damage, and this should always be considered and investigated in cases of babesiosis.
Acute respiratory distress syndrome is a severe, usually catastrophic complication of babesiosis. Dogs will experience a sudden increase in their respiratory rate, develop severely labored breathing, and may cough up frothy blood-tinged foam. This frothy discharge may come from the nose as well. A blood test that measures how well the lungs are oxygenating the blood confirms severe lung impairment. Radiographs also help confirm the diagnosis. This is a grave complication of the disorder, and most dogs succumb.
Dogs with babesiosis will occasionally present in shock. They will often be collapsed, and have either weak or bounding pulses, and pale or jaundiced gums. This is a life-threatening complication of babesiosis and requires immediate emergency care.
Diagnosis In-depth of Babesiosis in Dogs
- Complete blood count, chemistry panel, and urinalysis. These routine tests do not diagnose babesiosis directly, but can reveal abnormalities consistent with the disease and help assess the severity and presence of complications. The complete blood count often shows anemia, low platelets, and high white count. Chemistry panel abnormalities vary with the severity of the disease. Uncomplicated cases typically have no biochemical changes. Complicated cases may have a variety of abnormalities. Urinalysis may also show a variety of complications, depending on the severity the disease and presence or absence of complications.
- Evaluation of a blood smear. Babesiosis is diagnosed based on demonstrating Babesia organisms within infected red blood cells on a blood smear. Large pear-shaped organisms, present in pairs, indicate Babesia canis infection, while smaller organisms present singularly are Babesia gibsoni.
- Serology. This test detects antibodies to the organism in the bloodstream, and has the advantage of detecting infection in cases where the number of parasites infecting the blood cells is low.
Therapy In-depth of Babesiosis in Dogs
The primary goals of treatment in dogs are to eliminate or suppress the Babesia organism, and reverse the life-threatening anemia. Mild uncomplicated cases only require anti-Babesia therapy. Severe cases require anti-Babesia therapy plus a blood transfusion. Complicated cases require additional therapy, depending on the complication. Three drugs are known to be effective as anti-Babesial medications.
- Diminazene aceturate. One dose of this drug, injected into the muscle, is effective in treating uncomplicated Babesia canis infections. The drug has a narrow margin of safety, and severe or potentially fatal neurologic side effects may develop if overdosed.
- Imidocarb. One dose injected into the muscle or under the skin is effective in treating babesiosis. The injection is painful, and side effects may occur, although they are not as severe as with diminazene aceturate.
- Trypan blue. This drug alleviates clinical signs and suppresses the organism in the bloodstream by blocking its entry into the red blood cells. It does not eliminate infection. It is given intravenously and is very safe, making it a good drug to use initially in severe cases. Once the dog is on the mend, diminazene aceturate or imidocarb is given in an attempt to eliminate the infection.
- Blood transfusions. Dogs with severe anemia will require a blood transfusion to stabilize them.
- Supportive care. Depending on which complications may or may not be present, dogs may require additional laboratory tests and therapeutics, such as intravenous fluids, medication, or placement in an oxygen cage.
Follow-up Care for Dogs with Babesia Infection
Optimal treatment for your dog requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your dog does not rapidly improve.
Administer all prescribed medications as directed. Alert your veterinarian if you are experiencing problems treating your dog.