Downeast Dog News


By Gail D. Mason, DVM, MA, DACVIM | Apr 01, 2019

Ticks are more than just creepy little pests. They can spread numerous diseases to people and pets. The tick population is on the rise, and that includes here in the northeast. Most owners are aware of the danger of Lyme disease. But did you know that ticks can carry other diseases? Worse yet, they can transmit more than one disease at a time. These “vector-borne” diseases can be slow or rapid in onset and can produce a variety of symptoms. The more you know, the better you can protect your best buddies.

EHRLICHIA are a type of bacteria that attack and live within the white blood cells of the humans and animals. In the U.S., EHRLICHIOSIS is spread by the brown dog tick, though it is not yet known how long that a tick needs to be attached to the host in order to transmit the disease. The onset of illness is about 1-3 weeks after the tick bite. During this first phase of illness, a dog may become listless, febrile, and off food. Your veterinarian may discover that your dog has swollen lymph nodes, a low platelet count (thrombocytopenia), and anemia. The good news is that most dogs recover rapidly with antibiotics (typically doxycycline or minocycline). If left untreated, some dogs develop a chronic form of the disease which includes kidney disease, ocular disease, and life-threatening bleeding.

ANAPLASMOSIS or “dog tick fever” is found throughout the U.S. and can pose a serious health risk. It is transmitted by deer ticks that require only a 24-hour attachment for disease transmission. The symptoms can be vague or severe and include fever, loss of appetite, lethargy, stiffness, vomiting, diarrhea, and even seizures. Blood tests may show increased or decreased white blood cell count, anemia, and thrombocytopenia. ANAPLASMOSIS luckily responds to treatment with doxycycline, but patients may need hospitalization and supportive care such as intravenous fluids, pain-relievers, and antiemetics.

ROCKY MOUNTAIN SPOTTED FEVER (RMSF) is caused by an intracellular Rickettsial organism transmitted by the Rocky Mountain wood tick, the American dog tick, and the brown dog tick. Despite its geographical reference, this disease can occur in the northeast. Transmission time by the tick is 5-20 hours, and the onset of illness is 2-14 days after the bite. Symptoms of the disease can occur in any organ of the dog’s body as the organism attacks small blood vessels. The result may be fever, lethargy, loss of appetite, enlarged lymph nodes, lameness, cough, swelling of the limbs (edema), bruising or necrosis of the skin, and hemorrhage (especially nosebleeds). About 1/3 of dogs will also exhibit neurological signs including incoordination, spinal pain, dullness, or seizures. Most, but not all patients with RMSF respond to doxycycline, minocycline, chloramphenicol, or enrofloxacin. Affected dogs usually benefit from hospitalization, intravenous fluids, antibiotics, antiemetics, and pain control. Blood transfusions can be life-saving in severely affected patients.

BABESIOSIS is the result of Babesia organisms transmitted to dogs and people by the American dog tick and the brown dog tick after a 2-3-day host attachment. It can also be spread by dog bites and to pups during gestation. Young dogs, especially Pit Bull terriers, are at increased risk for this infection. The organism invades red blood cells and causes their destruction. The massive red blood cell destruction by the immune system results in a severe, secondary inflammatory reaction. Common symptoms include lethargy, weakness, anemia, jaundice, red urine, and pale gums/skin. This illness is life-threatening in its fulminate form. Intensive veterinary care, which can provide blood transfusions, supportive medications, and injectable drugs such as imidocarb or atovaquone may be required.

As you can see, vector-borne illnesses can be mild to life-threatening. Moreover, symptoms can overlap, which can make diagnosis difficult. Severe illness caused by any of these organisms must be distinguished from other systemic infections, toxicities, and certain cancers (such as leukemia). Your veterinarian has access to advanced diagnostic testing such as serum antibody screens and “polymerase chain reaction “or PCR assays which can detect the actual nucleic acids of the organisms in the patient’s bloodstream.

Since the test results are not available immediately, many veterinarians will treat the patient empirically with doxycycline while results are pending. This is a safe and prudent therapeutic plan. When clinical signs are severe, supportive therapy is key to controlling patient hydration, pain, hemorrhage, inflammation, and vomiting. As well, the likelihood and speed of patient recovery can be greatly enhanced.

Your veterinarian can help you choose which methods of tick control may be most effective for your pet to fight these tiny monsters. Using such methods, along with performing a daily “tick check” and keeping your lawn/dog yards mown short, can reduce your dog’s risk of contracting serious infections.