Every year it is recommended that dogs are tested for heartworm disease regardless of being on year round heartworm prevention. The most common heartworm test will also test for three tick borne diseases. While heart worm disease is carried by mosquitos, tick born disease are transmitted by ticks , as the name suggests. The three most common diseases are Anaplasmosis, Ehrlichiosis, and Lyme disease. While all three are bacteria that live in the blood, each has its own symptoms and potential long term effects.
Anaplasmosis is a bacteria that infects a dogs bloodstream; it also can infect humans. Anaplasma phagocytophilum is the most common form of the disease and is carried by the deer tick. The other form of the disease is Anaplasma platys, which is carried by the brown dog tick. Symptoms of the A. phagocytophilum can be vague, including fever, tiredness, lack of appetite and joint pain. Less common symptoms can include vomiting, diarrhea and/or respiratory signs like coughing or labored breathing. Since the symptoms can be similar to Lyme disease, anaplasmosis can be misdiagnosed.
It is possible for dogs to be chronically infected and not have any symptoms. A. platys is a more severe form of the disease, that effects the body’s ability to stop bleeding, which can be life threatening. Typical treatment for both forms of the disease requires a month or longer of Doxycycline, an antibiotic. Most dogs will start to feel better within 24-48 hours of starting treatment. It is recommended to retest 6 months after treatment to make sure it has been resolved.
Ehrlichiosis is also a bacteria that will infect a dogs bloodstream. Ehrlichia canis is the most common form seen in dogs, and is carried by the brown dog tick. There are other Ehrlichia species, some can also infect humans. Symptoms of Ehrlichiosis include fever, exercise intolerance, depression, lack of appetite, stiffness and swelling of the limbs. Ehrlichia can cause enlarged lymph nodes, spleen and a low platelet count (platelets are blood cell that allow the body to stop bleeding). Severe infections can be very serious and lead to severe weight loss, kidney failure, meningitis (infection of the brain), loss of the body’s ability to stop bleeding and even death. There are some dogs with chronic infections that show no outward signs. Typical treatment includes a month or more of Doxycycline. In the severe cases supportive care and hospitalization might be required to stabilize the dog. It is recommended to retest 6 months after finishing treatment.
Lyme disease is caused by the bacteria Borrelia burgdorferi, and can infect dogs, cats, horses and humans. Transmission requires that a tick be attached to an animal (or human) for longer than 24 hours. This is why it is important to remove all attached as quickly as possible. Symptoms in dogs included intermittent/ recurrent lameness, fever, tiredness, swollen and painful joints. Lyme disease can also cause kidney failure, which unfortunately is often fatal. As with the other tick borne diseases treatment is a month or longer course of Doxycycline. If the signs return an additional course of antibiotics might be needed, since persistent infections are common. To help with the joint pain an anti-inflammatory pain medication such as Rimadyl might also be prescribed. Unfortunately, even if the bacteria is cleared the damage done to the joints might cause lifelong arthritis. Again retesting in 6 months after treatment recommended, though as mentioned some dogs will remain infected for life.
Year round tick prevention is recommended to prevent all of these diseases, options include topical, oral or collars. There is also a vaccine available for Lyme disease if your dog is at a high risk. A high risk animal would be one that goes into hiking, lives in a more rural area with lots of tree and grasses or spends anytime in high tick invested areas. Please ask your veterinarian about your dog’s potential risk and if the Lyme vaccine is recommended. As with heartworm disease yearly tests are recommended since many dogs can have no outward signs of these diseases.
Dr. Reese Douglas is a graduate of Oregon State University. She has special interests in exotics, zoology, and aquatics.