By: Cate Burnett
Ticks and Canine Lyme Disease – What To Watch For With Our Pets
According to the Companion Animal Parasite Council, 5686 dogs out of 34,545 tested positive for tick-borne diseases, including Lyme disease and Ehrlichiosis, in the state of Texas in 2015. As of this publication date in 2016, 754 dogs have already shown as positive. With warmer weather now upon us, the tick population in the southern US is expanding. This increases the chances of our canine companions contracting these deadly diseases.
Because April is Prevention of Lyme Disease in Dogs Month, we want to place the focus on this chronic and painful disease and discuss what we as pet parents can do to keep our dogs healthy and happy year round.
History of Lyme Disease and Geographical Regions
Veterinarians first diagnosed canine Lyme disease in Connecticut in 1975, although scientific evidence indicates that the ailment has existed in wildlife for a number of years. Recent DNA testing to preserved tissue from a mouse that died in 1894 shows that the mouse was infected with the disease.
Dogs throughout the US can by affected by Lyme disease; however, it is only prevalent in wooded and rural areas where there is a high concentration of ticks. Eighty-five percent of all cases occur in the eastern coastal states from Maine to Virginia. The Northern Plains states and the Mid-West (Wisconsin, Minnesota, Michigan) account for the second highest incidence level of reported disease. The West Coast and the Southeastern states from Texas to Georgia and the Floridian peninsula rank next.
The reported increase of Lyme disease in the 20th Century is thought to be due to certain environmental factors. Prior to 1900, areas of this country were heavily settled and deforested, reducing native deer populations and the deer ticks that carry Lyme disease. Now that many of those same areas are being re-planted and restored, the numbers of deer are increasing. This coupled with increased awareness and testing capabilities has led to the greatly increased reporting of the disease.
Transmission of Lyme Disease and Life Cycle of the Tick
Lyme disease is caused by Borrelia burgdorferi, a type of bacteria call a ‘spirochete’ for its spiral shape. The primary carriers of this bacterium are the Eastern black-legged tick (also called the deer tick) and the Western black-legged tick. Extremely small, ranging in size from a grain of sand to a sesame seed, black-legged ticks live in shady, moist ground and can be found clinging to tall grasses, brush, shrubs, and low-hanging tree branches. They can also be found in gardens and lawns at the edges of wooded areas where deer and mice, the ticks’ preferred hosts, flourish.
Just about this time of year in the spring, tick larvae begin to emerge from eggs that were laid in the fall. The larvae feeds on small woodland mammals like mice and, if the mouse is infected, the larva enters the tick’s body through its saliva. This infected larva grows until the following spring where it molts into an adult tick. The infected adult tick then feeds on a larger mammal – namely your dog or you – and passes the B. burgdorferi into the bloodstream.
For the tick to transmit the bacteria, it must be attached to its victim for about 48 hours. If the tick dies or is removed before that time, transmission of the bacteria does not occur. Even if the tick is attached for more than 48 hours, your dog may not contract the disease.
Infected dogs pose no risk of transmitting the Lyme disease to other canine or human members of the household. After a full meal (the allotted 48 hours), ticks detach and don’t feed again for several days. There is a risk from ticks that have not eaten fully and become detached in that they might seek out another mammal to feed and pass on the infection.
Symptoms of Canine Lyme Disease
The clinical signs of Lyme disease typically occur 2 to 5 months after a bite from an infected tick. Unlike humans, dogs do not develop the rash or circular red area commonly seen around the tick bite.
Your infected dog may present with…
•A high, persistent fever of between 103 and 105ºF
•Swollen lymph nodes
•Joint swelling and inflammation
•Loss of appetite
•Stiff walk with an arched back
Additionally, some dogs develop chronic, progressive kidney disease as a result of the Lyme disease. Because this consequence is extremely difficult to treat, most veterinarians will recommend running additional blood work on your affected dog to check for continuing renal function. Chronic cardiac problems and nervous disorders have also been seen in some pets diagnosed with Lyme disease.
The clinical signs of Lyme disease may be ongoing and chronic. Some dogs can be perfectly fine one day and showing symptoms the next. A proper diagnosis and long-term veterinary treatment are typically necessary to clear your dog of the organism and prevent a relapse.
All breeds of dogs are equally susceptible to Lyme disease, though dogs used for hunting or other outdoor sporting activities are at higher risk for exposure to ticks.
Lyme disease is usually diagnosed based on a medical history that includes the possibility of tick exposure, suspicious clinical signs, and results of diagnostic testing.
Several laboratory tests can identify the B. burgdorferi organism in blood or tissues. Additionally, a quantitative antibody test (QC6) can measure the level of antibodies in the bloodstream of your affected dog to determine whether treatment is recommended.
More commonly, veterinarians use an in-clinic SNAP test to check for all tick-borne diseases including Lyme disease, ehrlichiosis and anaplasmosis. Similar to the common heartworm test, this SNAP test is very accurate, uses only a tiny amount of blood and only takes a few minutes to show results.
Your veterinarian may recommend additional diagnostic tests if your dog shows signs that other organs may be affected by the bacteria causing the Lyme disease.
Treatment and Prognosis
Treatment of Lyme disease generally consists of administration of antibiotics and (if necessary) other medications to temporarily help control joint pain and other clinical signs. Doxycycline is the most common antibiotic that is prescribed for Lyme disease, but others are also available and effective.
Your dog will probably be treated as an outpatient unless other ailments relative to the Lyme disease (severe kidney and/or cardiac involvement) are detected.
Some dogs show dramatic improvement after only a few days of receiving antibiotics, but most veterinarians now recommend a 28- to 30-day course of treatment. Unfortunately, the antibiotic treatment does not always completely eliminate infection with B. burgdorferi bacteria. Relapses are not uncommon, so pet parents are advised to monitor their dogs carefully for signs of illness.
Protection from Lyme Disease
The best protection against Lyme disease is prevention. Prevention means:
•Give your pet a flea and tick preventative that can help ensure an infected tick that attaches itself dies before reaching the 48-hour mark, that time period necessary to transmit the disease. Be sure to discuss preventatives with your vet so they can recommend one that is suitable according to your dog’s risk.
•Keep your pets away from tall grass and wooded areas to decrease their exposure to ticks, thus decreasing the odds of getting bit.
•Vaccinations have been developed that help protect against Lyme disease. This is something you should discuss with your veterinarian to decide whether this method of prevention is right for you.
Please Note: If you suspect the tick found on your dog is a black-legged tick, save the tick in a sealed container of alcohol and take it, and your pet, directly to your veterinarian for diagnostic testing.
A quick diagnosis and early treatment can save your pet from a painful, and sometimes deadly, disease.
Cate Burnette is a semi-retired registered veterinary technician with clinical experience in small and large animal medicine. With 30-plus years of journalism experience, she went back to school after 9/11 to work with her first love: animals. The pet parent of four cats, three dogs and one ex-racehorse, Cate is a certified rescue volunteer with the American Humane Association’s Red Star Emergency Services and served with the group in New Orleans doing animal search and rescue after Hurricane Katrina. She is also a horse safety and horse management expert, and has volunteered with US Pony Clubs as a district commissioner and horse management judge.