What is babesiosis?
Babesiosis is a tick-borne infection caused by protozoal parasites of the Babesia genus. Babesia invades mammalian red blood cells, causing anemia. Babesia species are found worldwide. In North America, most canine cases of babesiosis occur in the southern United States; however, reports in other areas of the US and Europe are increasing. The American Staffordshire and American pit bull terrier are the breeds most diagnosed with this condition.
How does a dog contract babesiosis?
Babesiosis can be transmitted in several ways:
- Through an infected tick's bite (multiple tick species can carry the disease)
- Animal-to-animal, like when an infected dog with oral lesions or abrasions bites another dog
- Mother to unborn puppies (when puppies are in the mother’s uterus)
- Tainted blood transfusion
What are the clinical signs of babesiosis?
Dogs infected with babesiosis may present with a wide variety of clinical signs, ranging in severity from sudden collapse with systemic shock, to a hemolytic crisis (the body attacks and destroys red blood cells), to a subtle and slowly progressing infection with no apparent clinical signs.
Dogs typically present with the acute and severe form of babesiosis, characterized by:
- Abnormal dark urine
- Fever
- Weakness
- Pale mucous membranes
- Depression
- Swollen lymph nodes
- Enlarged spleen
Blood and urine tests may reveal anemia, thrombocytopenia (low platelets), hypoalbuminemia (low albumin, a blood protein), and bilirubinuria (a pigment that results from breaking down red blood cells found in the urine).
How is babesiosis diagnosed?
In the past, babesiosis was diagnosed by identifying the parasite on a blood smear. Other diagnostic tests are now more readily available, including:
- Fluorescent antibody (FA) staining of the organism
- Enzyme-linked immunosorbent assay (ELISA)
- Polymerase chain reaction (PCR) test (can determine the Babesia species causing the clinical signs)
Serologic or antibody titer testing are also used, but they have their limitations. A positive test result depends on an antibody response in the infected dog, which may take up to 10 days to develop. Once a dog has developed antibodies to babesiosis, they may persist for years, which must be considered in any subsequent tests.
How is babesiosis treated?
A variety of medications are available for babesiosis treatment, including:
- Atovaquone
- Atovaquone/proguanil (Malarone®)
- Diminazene aceturate
- Imidocarb dipropionate
These medications may be combined with antibiotics, such as clindamycin or azathioprine. Other antibiotic combination treatments may also be used, including doxycycline, metronidazole, and enrofloxacin. Depending on the severity of your dog’s condition, other supportive treatments may be recommended, such as blood transfusions and intravenous fluids.
What is the prognosis for a dog diagnosed with babesiosis?
The prognosis for dogs diagnosed with babesiosis depends on which body systems are affected. Be aware that dogs who survive babesiosis often remain sub-clinically infected, which means the parasite is present in the body, but the dog has no noticeable signs of illness. These dogs may suffer a disease relapse in the future or may be a source of further disease spread. Dogs that recover from babesiosis should never be used as donors for blood transfusions because the recipients may develop the disease.
Currently, there is no effective vaccine available to protect dogs against babesiosis. Since babesiosis can be spread by ticks, you should use tick preventatives, such as Afoxolaner (Nexguard®) or Sarolaner (Simparica®), to reduce the risk of infection.
Can humans get babesiosis?
Yes, humans can develop babesiosis. Although several species have been reported, the most common species infecting humans is Babesia microti, transmitted by the deer tick or black-legged tick.
