PBRC Medical Tip

Pit Bull type dogs are more prone to become infected with Babesia gibsoni than any other breed and are more likely to suffer clinical infections of Babesia canis than other breeds. Here's what you should know.....

What is Babesia and what is it doing to your dog?

There are many species of Babesia, but those of most concern to Pit Bull owners are Babesia canis and Babesia gibsoni. While any dog can become infected Babesia organisms, infections are most commonly found in Greyhounds and Pit Bulls. Although there are Babesia species found all over the world, in the United States B. canis and gibsoni are more prevalent in southern states. However, the transient nature of families and the transfer of dog ownership due to rescue from natural or manmade disasters, there is no state that is unaffected. Some countries do require pre export negative Babesia canis and/or gibsoni test results prior to allowing entry.

How does this happen?

An infected tick must feed on a dog for 2-3 days to transfer the babesia organism. Once this transfer occurs, the babesia organism continues to develop as it moves from the blood stream into red blood cells (rbc). When the organism matures in the rbc, that cell will rupture and release the organism in the blood stream to infect additional rbcs. The body’s own immune system will also detect the infected red blood cells and destroy them. Although Babesia is considered a tick bourne disease it can also be transmitted by dog bites, blood transfusions, contaminated needles or surgical instruments and from mother to pup.

What Babesia does?

The destruction of red blood cells can result in anemia (lack of red blood cells). Lab results may show this anemia (low rbc count), low platelet count, and other values suggestive of liver disease (hypoalbuminemia, and bilirubinuria). Initially, the anemia appears to be nonregenerative, but later is regenerative anemia. Clinical symptoms such as weakness, pale color, fever, anorexia, enlarged lymphnodes, depression, enlarged spleen, rapid pulse may be exhibited by some dogs. In dogs that have had a spleenectomy (spleens removed) or have an auto immune disorder the disease can be devastating. While many normal healthy dogs will have no outward symptoms at all, these dogs are carriers and will spread the disease to other dogs via dog bites and infecting ticks. During times of stress, due to other disease process or mental situations these dogs may also have a relapse of the disease and exhibit clinical symptoms. Dogs diagnosed with Auto Immune Hemolytic Anemia should have babesia on the list of rule outs as to the cause. Also dogs that are having liver issues and/or undiagnosed liver disease should have babesia on the list of rule outs.

How is Babesia diagnosed?

Babesia organisms can be seen on a blood smear, especially a freshly drawn blood taken from a capillary source (ear, toenail). If Babesia organisms are found, the patient is definitely infected. However, the organism can be hard to find and may rarely be found in samples from chronically infected dogs or carrier dogs that aren't showing symptoms of the disease. Due to this there are other, more ideal methods for testing. Indirect fluorescent antibody
(IFA) testing is performed on serum or plasma and is used to establish antibody titers to B. canis and gibsoni. However, if it is early in the disease process or in an animal that is immune suppressed, antibodies may not be present. A titer is a measurement of the amount or concentration of antibodies in a blood sample and can be helpful in determining medical
treatment. Generally the higher the titer, the greater the infection. IFA testing is available through specialized diagnostic laboratories, such as Protatek Reference Laboratory.

http://www.protatek.com/RefLab/index2.htm

Molecular diagnosis of Babesia spp. infection in dogs and cats via polymerase chain reaction (PCR) of whole blood has become available. This is an extremely sensitive test that can be used to diagnose Babesia and distinguish between the different species. However, it does not help establish the level of infection and there have been issues with false positive/negative results. To avoid this, blood samples should be collected early in the course of clinical disease,
before medications have been started and submitted to an experienced, quality lab.

When to test?

Food for thought is routinely screening Pit Bulls. One of my own dogs was negative for B. canis several years ago. Recently she tested positive. No tick exposure, no contaminated needles/ instruments, no blood transfusion. What did happen in the time in-between was an accidental fight with another of my dogs (who is positive for B. canis). Neither of my positive dogs (I also have 1 dog that has tested negative, who also has had accidental fights...) have clinical or laboratory results that indicate they have the disease. But I know that it is there and if they do have other medical or stress issues that could allow the Babesia to become a problem I know to watch for it. Any dog blood donor should be tested prior to joining a donor program and periodically during their blood donor career. Any dog intended for breeding should be tested prior to entering into a breeding relationship (both male and female) any dog with liver disease. Dogs with AIHA. Dogs exhibiting clinical signs.

How to treat?

Treatable but not necessarily curable (meaning can reduce eliminate symptoms, but may still test positive and should always be considered a permanent carrier). B. canis is easier to treat than B. gibsoni. *note* there are other treatment options available in different areas of the country and currently under development in the US

Doxycycline (DO NOT GIVE WITH DAIRY PRODUCTS)and Clindamycin are affordable,
generally well tolerated treatment option for dogs with low to moderate titers and no or little symptoms.

In the US the "big gun" treatment is Imidocarb Dipropionate A single dose is usually effective for Babesia canis but 2 injections (given 2 weeks apart) are needed for Babesia gibsoni and depending on the infection of Babesia canis may be given. Side effects can include, but are not limited to: muscle tremors, drooling, elevated heart rate, shivering, and fever, facial swelling, tearing of the eyes, and restlessness. The injection is expensive, painful, should be given deep into the muscle, given with supportive care and only by doctors experienced with it. Pre-treatment with an injection of atropine helps palliate these side effects. In dogs that are
asymptomatic, this treatment is not worth the risks and side effects.

Prevention:

• Tick control. Carefully remove ticks asap.
• If blood transfusion is needed confirm that blood is from a babesia negative dog. (as well as other tick bourne diseases).
• Avoid dog to dog bites, fights.
• Avoid situations that involve contaminated needles/surgicalinstruments

Other things to consider:

• First evident within rbcs on blood smears in approximately 1 to 3 weeks post initial infection.
• Although clinical disease may resolve, infections often become chronic. Even after appropriate therapy, infection can persist forthe life of the dog.
• Babesia canis and B. gibsoni are not known to infect people.
• People can become infected with other Babesia species, dogs are not involved in the transmission.
• A babesia vaccine exists, although it is not currently available in the US.
  

Educate yourself and talk to your veterinarian!