Advances in Lyme Disease Detection
Learn how you can protect against this deadly tick-borne disease
Deb Eldredge, DVM
Lyme Disease is a tick-borne disease that has spread over much of North America. (See www.dogsandticks.com/NA-map-lyme-disease-dogs/index.html.) Lyme Disease cases have been reported from every state and province in Canada.
While the Northeast, Midwest and pockets in the Southwest and South account for most of the cases, the ticks that carry Lyme Disease and the disease itself have been seen everywhere. The first cases in canines were reported in 1984.
Certainly all dog show fanciers take steps to keep their dogs tick free. Many Toy breeds are put in raised ex-pens to eliminate and are carried virtually everywhere when they are outside so they should be tick free. Still, most dogs walk outside, play in the grass and show outside on grass at least part of the time.
Limiting your dog to cut grass helps keep tick exposures down, but many dogs, especially the males, prefer to urinate along the mowed fringe of tall vegetation. Ticks can be present in any of those areas year round.
While you may not live in a major tick disease area, many dogs travel, especially in the summer months, to shows that are held in tick areas. The show itself may be held outside or your dog can be exposed simply when walking around the hotel at night. Certainly it makes sense to provide your dogs with some type of tick protection — even if it is as simple as daily flea combings to detect any ticks early on. There are excellent topical repellants that most dogs tolerate well or you can experiment with natural oils such as neem oil, citronella and geranium.
Dogs infected with Lyme Disease tend to show up with fevers, swollen lymph nodes and swollen joints as well as lameness. Some dogs will go on to develop a severe kidney infection. While many dogs respond quickly and favorably to antibiotic medications such as doxycycline, some dogs appear to develop chronic carrier states. These dogs will break out with signs again if they are highly stressed.
There are Lyme Disease vaccines for dogs. It is recommended that a dog have an initial set of two vaccines, then annual boosters. The causative agent of Lyme Disease is the spirochete, Borrelia burgdorferi. Since this is not a virus, but rather a bacteria, you may hear the vaccine referred to as a “bacterin.” Immunity to bacteria is generally not as long lasting as immunity to viruses. That is the reason behind the recommendation for annual boosters.
Lyme Disease vaccines are not one of the “core vaccines” recommended by the American Animal Hospital Association. Whether or not vaccination makes sense for your individual dog depends on your dog’s environment and lifestyle. If you have a German Shorthaired Pointer that hunts in the upper Midwest on fall weekends, vaccinating for Lyme Disease may make sense for your dog. If you have a Maltese that lives in a New York City high-rise apartment, you can probably skip this vaccine.
Whether or not you vaccinate your dog, many dog owners are including screening for Lyme Disease along with their annual screening for heartworm disease. A popular test has been the Idexx 4 Way that tests for heartworm and three tick-borne illnesses. Many clubs organize spring health clinics for members and use this screening test. This is a quick and easy screening test, but it can’t distinguish between vaccinated dogs and ill dogs or tell if a dog is in early stages of Lyme Disease or a chronic disease state.
The Animal Health Diagnostic Laboratory at Cornell has announced a new multiplex Lyme assay which will replace the current ELISA and Western Blot tests. (See more info at /redirect.aspx?location=http://ahdc.vet.cornell.edu/docs/Lyme_Disease_Multiplex_Testing_for_Dogs.pdf.)
This test will look at three surface antigens on the Borrelia spirochete: the OspA, OspC and OspF. The Borrelia changes which antigens are expressed over time. OspA is expressed first, but gives way to OspC in your dog’s body. With time, the antigen will shift to OspF which is seen in chronic cases of Lyme.
OspA disappears rapidly once it is in your dog. However, vaccinated dogs will still show a response to this antigen. This has confused test results in the past. OspC antibodies will indicate that a dog is in the early stages of infection — generally from two to three weeks after infection and will last until three to five months post-infection. Meanwhile OspF responses show up at about six to eight weeks after infection and will remain in dogs with chronic infections.
This new Multiplex test will provide your veterinarian with additional information to help plan your dog’s treatment. The test will show if your dog was previously vaccinated and if the vaccination actually caused an immune response. This could be a great benefit for anyone working in rescue with dogs of unknown vaccine histories. In addition, the test will show if your dog is acutely infected or has had a low-level chronic infection for a period of time. Strategies about which antibiotic to use and for how long may be influenced by these test results.
Any dog that has the clinical signs to fit Lyme Disease would benefit from having this test done. Deer ticks are quite small and can easily be missed on your dog, especially in the coated breeds. Deer and other hosts for these ticks are seen throughout North America. Many suburbs and even cities have stable deer populations. Dogs that test positive on the rapid screening test would benefit from the additional information garnered from this test as well.
The new test requires two mL’s of serum (from a blood sample). Testing is run at the Animal Health Diagnostic Laboratory three days a week. Accordingly, results are generally available two to three days after the sample arrives at the facility. Check test dates before having blood drawn to arrange for the fastest results.
Your veterinarian can access forms at the website. The cost for running the test is $36, but you should be prepared to pay extra for blood-drawing fees and for shipping costs.
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