Babesiosis (also called Babesia infection) is a disease passed to mammals via ticks. The Babesia parasite is a microscopic organism that takes up residence the dog’s red blood cells and eventually destroys the RBCs, which causes the animal to become anemic. Babesiosis is the second most common blood parasite disorder of all mammals, although most people have never even heard of the parasite.
Often, the dog’s immune system attacks the invaders and destroys the cells in which the organism lives. This, unfortunately, also leads to anemia.
There are two main types of Babesia, and others that are not commonly seen. The two major types are Babesia canis (“large Babesia”) and Babesia gibsoni (“small Babesia”).
A tick passes the parasite to a dog through its saliva when it picks up the parasite from its previous host (a mouse, squirrel, deer, or other mammal) and bites the dog. For a tick to pass the organism on to a dog, it must feed for two to three days. Once the Babesia passes into the dog’s bloodstream, it attaches to the exterior of a red blood cell and eventually penetrates the cell. Once inside, it starts to multiply and incubates for about two weeks. During that time, the Babesia causes the dog’s RBSs to clump together. These damages cells will eventually rupture (called hemolysis) and overspill into the blood stream. The invasion awakens the dog’s immune system, and it starts to attack red blood cells in an effort to kill the parasite. This can cause autoimmune hemolytic anemia.
Infected dogs may pass the parasite to their unborn puppies, or to another dog or mammal through biting.
The simplest way to prevent Babesia infection is to control the tick population in your area. Keep long grasses, weeds, and brush trimmed in your yard, and inspect your dog each time it comes in from out of doors. Remove ticks from your dog as quickly as possible. Make sure you wear gloves during the removal; many microorganisms found in ticks’ blood is dangerous to people, too. It may be beneficial to call your vet before you dispose of the tick, since he or she may want to identify and analyse it for potentially infectious diseases. Never flush a tick down the toilet, since it can survive and live to infect another animal. Instead, put it in a tightly closed container in the garbage, along with some water and rubbing alcohol or dish detergent.
If you live in a high-tick area and it’s impossible to control the tick population, you should consider a topical anti-tick product for use on your dog. There are many available commercially; speak to your vet about the best options.
All dogs who are potential blood donors should be screened for Babesiosis before their blood is accepted and shared with other dogs.
The severity of symptoms depends upon the severity of the Babesia infection and the extent of damage done to the dog’s red blood cells. Signs of Babesiosis are almost indistinguishable from those of anemia. Special testing is usually required to diagnose a Babesia infection. Symptoms include weight loss, reluctance to rise, weakness, exercise intolerance, pale mucous membranes, lethargy, ocular discharge, nasal discharge, fever, shortness of breath, lack of appetite, dark urine, disorientation, jaundice, diarrhea, dark stools, vomiting, history of dog fights or bite wounds, discoloured stools, history of tick bites, enlarged liver, lack of coordination, enlarged spleen or lymph nodes, and collapse.
Dogs at Risk
Overall, dogs that spend a lot of time outdoors in tick-infested areas – like those used as hunting companions – are at higher risk of developing this disease. Breed-wise, Greyhounds are more likely than all other breeds to develop Babesia canis, andn American Pit Bull Terriers are more likely to contract Babesia gibsoni. Others at risk include those who receive blood transfusions, dogs that fight with other dogs, and puppies whose mothers are infected.
Testing and Diagnosis
When Babesia infection is suspected, a serum biochemistry profile and complete blood count blood work should be drawn and analysed. Dogs infected with Babesiosis will show low circulating red blood cells and platelets. There may be an increase in circulating bilirubin, or glucose, as well. Stained blood smear tests will show either small or large Babesia organisms. Sometimes urinalysis may show elevated hemoglobin and/or bilirubin.
A Polymerase chain reaction test can show the presence of Babesia. This test can distinguish the species and even subspecies of the parasite. This test is rarely done, however, and is not available in all locations.
Treatment and Prognosis
Some dogs with severe Babesiosis may need to be hospitalized. Attached ticks must be removed. Dehydrated dogs require hydration via intravenous fluids. Some may need blood transfusions, particularly if severe anemia is present. Sometimes an immunosuppressant like prednisone is prescribed to help with any resulting immune disorders.
As long as the disease is diagnosed and treated in a timely fashion, prognosis is good. However, some dogs may show symptoms that go unnoticed until they develop severe anemia or low platelet count. These dogs may perish depending on immediate treatment options and the severity of the infliction.