Lyme Borreliosis

Lyme Borreliosis or Lyme disease is the most frequently diagnosed tick/insect-borne disease in the Untied States and in Texas. In humans, infection is initially characterized by flu-like symptoms and a circular rash but can ultimately result in chronic joint and nervous system problems.

Control of Lyme disease consists of avoiding tick and flea bites, thorough self examinations followed by prompt removal of attached ticks when engaging in outdoor activities, and keeping pets free of fleas and ticks since domestic animals can be responsible for bringing arthropods into the home environment.


Lyme Disease

It is interesting to note that Lyme Disease has become the most common tick-borne disease in North America and has become a significant threat to public health. Not only can you get Lyme Disease, your dog can also become infected by being bitten by an infected tick. Tick eggs live in the grass and weeds your dog may run through on family outings, daily walks, or during regular daily activities. Once attached to your furry canine companion, the eggs of the tick infest not only your dog but also his bedding and, ultimately, his home.

First discovered in humans in 1975 and later reported in dogs in 1984, Lyme Disease, or Borreliosis, continues to sweep across the country, effecting more victims each year. This disease is caused by the transmission of a bacteria known as Borrelia burgdorferi. Carriers of this bacteria are ticks, small parasites that live off the blood of other creatures. When an infected tick bites, the bacteria causing Lyme Disease is then transferred into the host's blood.

Lyme Disease is prevalent in North America and may exist in any region where Borrelia burgdorferi infected ticks live. To keep your pets and yourself safe, you should be wary of any tick you find attached to either yourself or your dog. Studies have shown that migratory birds have helped disperse the infected ticks, contributing to the spread of this disease. In addition, dogs and other animals that go into infested areas have the potential for carrying the infected ticks back into their own habitat. If you travel during the warm summer months and plan to take your dog with you, exercise caution in secluded or heavily wooded areas. These are natural environments for ticks and the Lyme Disease bacteria.

The signs of Lyme Disease are similar in both dogs and humans. Once infected, your dog may experience arthritis, sudden pain or lameness, fever, loss of energy, loss of appetite, and even depression. To properly diagnose Lyme Disease, blood tests may be performed to search for the disease fighting proteins known as antibodies after the symptoms of Lyme Disease have been observed. Sadly though, blood tests being used to diagnose this condition are often inconclusive. Lyme Disease in dogs may be treated by using broad spectrum antibiotics, but treatment may not always be successful. Vaccines available through your veterinarian were developed after years of careful testing for both effectiveness and safety. While no vaccine is ever 100% effective, the canine Lyme Disease vaccine has proven in studies to be highly effective. Following an initial series of vaccines given weeks apart, your pet should then receive an annual booster vaccine.

As a general rule of thumb, ticks remain active and feed until the daily temperature remains in the lower 40's. In most parts of the United States, the potential for exposure to ticks is moderate to high from April to November, but the risk of Lyme Disease a dog or other pet faces varies by season and the area of the country you live in. The best course of action to protect both your dog and yourself from ticks and the potential of Lyme Disease is precaution. Your veterinarian can recommend products, such as Frontline Top Spot, that will kill and repel ticks. In addition, using a long lasting yard spray in the dog house and under bushes will kill both tick eggs and larvae. In areas with no winter freeze to kill ticks, treating with a yard spray will probably need to be done twice a year. To further protect your pet, consider the following precautions:
 


If a tick is attached to the dog's skin, remove it carefully with tweezers, washing the affected bite area and your hands afterward.
 



Lyme Disease

"Fallout from the information highway." Laurie Brooke Adams found the original information on the Internet in a newsgroup called rec.pets.dogs and contacted Ms. Ginzberg for more information. That additional information follows this article as a question/answer section. Thanks to Ms. Ginzberg for allowing reprint and to Laurie for her submission.

I live in Connecticut, 15 miles from Old Lyme, CT, where Lyme disease was first identified, and which provided its namesake. My vet was involved in the original clinical trials of the canine Lyme vaccine for a number of years before it was released to the public in 1992, and has continued to be very heavily involved in ongoing veterinary research into canine Lyme Disease (LD) and its prevention and treatment. Also, I have personal experience with Lyme: one of my two dogs has had Lyme disease and so have I (I was diagnosed after I asked my doctor for a Lyme test BECAUSE my dog has tested positive -- otherwise I might never have found out that I had it too I had been to the doctor already because of not feeling well, and the doctor had originally told me that I had (ahem) arthritis and advancing age, and that I just needed to get more exercise and maybe lose a few pounds and learn to live with the fact that I wasn't getting any younger. So thank heavens my dog's positive Lyme test alerted me to ask to have myself tested for it).

A few points here which I know from my closer-than-desired contact with Lyme disease and its ongoing research:

1. There are more strains of the Lyme spirochete than what the canine vaccine covers. That is a known fact. What they DON'T know yet, is whether vaccination with the canine Lyme vaccine induces cross-immunity against the strains of Lyme which are similar to, but not the same as, the ones covered by the vaccine.

2. It is also known that some dogs can and do get Lyme Disease even though they were vaccinated against it. The percentage is small, but not zero.

3. Until recently, every dog who had ever been vaccinated ALWAYS tested positive for Lyme after receiving the vaccination, for the rest of its life. That was one of the effects of the vaccine. That meant that it was impossible to tell whether a vaccinated dog had become ill with LD or not. Just within the VERY recent past few months, a new test has come out which can be used to test dogs who HAVE been vaccinated against Lyme, to see if they have contracted the disease despite having been vaccinated. That is a very new capability, which was not available until VERY recently.

4. Some number of dogs, nobody knows how many, seem to seroconvert to a positive Lyme test, apparently indicating that they have contracted the Lyme spirochete -- WITHOUT ever having any symptoms. The current speculation is that SOME dogs (nobody knows how many) may develop immunity to Lyme through natural exposure (i.e., tick bites) without ever becoming ill. This phenomenon is still being studied; nobody knows what it means yet.

5. Signs of Lyme in dogs can be very subtle, i.e., slight stiffness or lameness upon first rising. One might not suspect Lyme, especially in older or already arthritic dogs. Dogs do not get a characteristic rash, like many humans do.

6. A dog who has HAD and been successfully treated for Lyme Disease, should STILL receive a Lyme vaccination after the dog has been treated. The vaccine DOES provide additional immunity, and yes, humans and dogs CAN get Lyme more than once.

7. Whether or not to vaccinate depends on the dog's risk of exposure. Whatever you decide is a calculated risk, of course. If your dog travels a lot or is in contact with other dogs from other parts of the country, it probably should be vaccinated. It is known that Lyme Disease can be transmitted between cows and horses via being splashed with an infected animal's urine. This has not been proven DEFINITIVELY yet in dogs, but it is suspected to be likely that it is possible. So show dogs and dogs who travel or come in contact with large numbers of other dogs from outside their immediate areas should be vaccinated, regardless of whether their individual risk is low.

8. No inter-species transmission between mammals (i.e., from dog to human, or from horse to human, etc.) has been documented yet. However, there is a very high correlation between the incidence of Lyme among animals and the incidence of Lyme in people living in the same area. So if you have any animals who have ever had Lyme Disease, you should be tested for it yourself if you feel at all ill or otherwise off-peak, health-wise.

What about treatments?

I hate to say this, but the cost of "treatment" may also be a problem. The average cost of treatment of (Human) Late-Stage Disseminated Lyme is over $37,000. EARLY treatment of Lyme is easy and cheap. The longer you have UNTREATED Lyme, the more expensive and difficult it becomes to treat. There are some doctors who believe that there is a chronic form of it which cannot be cured, which patients can get after years of going untreated.

This is why it is ABSOLUTELY CRITICAL that physicians be convinced to offer patients with simple exposure and "early possible" symptoms of Lyme, a $10, 2-week course of cheap antibiotics, which WILL cure it at that point. Later on, that is too little, too late.

Q. My dentist diagnosed herself and treated herself without testing, and seems fine now. I have had these symptoms about three years, since I was in an area in the Northeast where I had to be outdoors a lot for a few days for a National. Did find some tiny ticks in my clothes after spending a day at St. Hubert's Giralda in New Jersey.

A. You DO have a definite history of exposure and symptoms which should indicate that you should be treated just on clinical diagnosis alone. Perhaps your dentist would be willing to prescribe Doxycycline or Amoxicillin for you (the first drugs which you would try -- probably for no less than one month to start, given the length of your history of symptoms and the possible time of exposure). Neither Doxycycline nor Amoxicillin will break your bank account - not just a one month supply anyway.

I really urge you to be aggressive about acquiring proper treatment for yourself. Untreated Lyme can cripple and debilitate otherwise healthy children and adults (1/2 of all Lyme patients are children under 12). Of those who testified before Congress earlier this year, many untreated Lyme patients testified that they are now unable to hold jobs, unable to walk, unable to read or write (due to one common symptom of advanced stage Lyme: dyslexia), some were unable to feed themselves, some had suffered severe brain damage giving them Alzheimer-like symptoms, and heart and kidney damage is common. It MUST be treated -- it does NOT "just go away" if you "wait long enough." It is progressive and debilitating. Given the history you have told me, you really MUST seek and find effective treatment, OR definitive proof that you do not have it. Don't let your doctor be lazy. My doctor told me that my symptoms were "menopause" (when I was 39 years old!!!), while at the same time refusing to test me for Lyme because she thought I was being "hysterical." I had to switch doctors just to get tested (which test came out with an almost-off-the-scale high positive).

Q. What breed(s) do you have?

A. I have a Cocker Spaniel who competes in Obedience and is training for AKC Hunting Tests, and a mixed breed (Siberian/GSD) who does Agility. And, I am the list owner for the Flushing Spaniel list, spanie-l. :-) I also assist in teaching Beginning Obedience classes at a local Training Center. It was the cocker who had Lyme Disease. I think she and I both got it while doing field training (TONS of ticks).

Anyone who has come in contact with this disease (human or dog) is welcome to write The Reporter about their experiences. Note that it is suggested by Dr. Stockner that if you do vaccinate for Lyme that you perform the test several weeks after vaccination to get a "baseline" level of the titer for future reference when the actual disease may be suspected.


Veterinarians still faced with difficulties in diagnosing Lyme disease

By Steven A. Levy, DVM   Contributing Author

Lyme disease is an infectious, tick-borne zoonotic disease first recognized as a clinical entity in humans in 1975 and in dogs in 1984.

The etiologic organism, Borrelia burgdorferi, is a spirochete which is transmitted by ticks in the Ixodes ricinus complex.

In the eastern and midwestern United States, Ixodes scapularis is the vector and in the western coastal United States the disease is vectored by Ixodes pacificus. In areas highly endemic for the transmission of Borrelia burgdorferi, the ecology associated with infection is often well understood. Conversely, in areas where the infection is emerging, the ecology may not be fully known due to a lack of detailed study or to the adaptation of the organism to transmission cycles involving alternate hosts.

A recent paper in the human medical literature examining emerging bacterial zoonotic and vector-borne diseases remarked that these infections "often lack a unique clinical presentation" and a "sensitive, specific diagnostic test. Thus, these infections are under-diagnosed... A case in point is Lyme disease" once "regarded as an obscure problem" but now "the most frequently diagnosed, yet poorly controlled, arthropod-transmitted disease in the United States." (Journal of the American Medical Association 1996; 275:463-469.)

Diagnosis

Veterinary medicine is likewise grappling with the dilemma of diagnosing Lyme disease in companion animals: lack of an accurate diagnostic test for Lyme disease, as opposed to an assay for prior exposure to the Lyme organism, and a broad array of presenting signs in effected patients make diagnosis an often confusing issue.

For the clinician, it is essential that a working clinical diagnosis be reached so that a course of therapy may be initiated in a timely fashion.

The first step in the diagnosis of Lyme disease is its inclusion in the differential diagnosis. Because it may affect the musculoskeletal, nervous, cardiac, renal and neurologic systems, Borrelia burgdorferi may be associated with a protean range of presenting signs in companion animals, yet many veterinarians never consider it as a possible cause of illness in their patients because they believe that exposure to the organism is unlikely or impossible in their area.

The Centers for Disease Control and Prevention (CDC) have reported cases of human Lyme disease in 47 of the lower 48 states.

Dogs have been reported to be at much greater risk for infection with Borrelia burgdorferi than humans in the same geographic region and it is therefore reasonable to expect that in areas where Lyme disease is emerging as a human entity it is also emerging as a veterinary concern.

Indicators that Borrelia burgdorferi is present in an area include:
 


When considering whether or not epidemiologic considerations warrant the inclusion of Lyme disease in a differential diagnosis, veterinarians are frustrated by either a lack of information or the preconceived notion that a specific area is not considered to have a risk for Lyme disease.

Such statements are often made without extensive field research into the presence or absence of Ixodes ticks or Borrelia burgdorferi. Even when attempts are made to identify vector ticks in an area where human cases have been reported, it may take years of investigation as evidenced by a case in Indiana where a veterinarian developed Lyme disease in 1985, entomologists failed to find Ixodes scapularis in 1986, and it was not until 1992 that ticks submitted independently by that veterinarian, and subsequently by a local taxidermist, verified the presence of Ixodes scapularis in that area.

Diagnostic criteria

While diagnostic criteria for humans have been standardized by the CDC, veterinary medicine has no such surveillance organization, and no standard diagnostic definition has been reached.

The clinical case definition for humans is presence of erythema migrans, the hallmark cutaneous lesion which occurs only in humans or presence of at least one late clinical manifestation and laboratory confirmation of infection. In all cases, alternate causes for clinical manifestations must be ruled out.

The greatest amount of clinical and laboratory study of companion animals has centered on the dog.

For this reason, specific syndromes and diagnostic criteria are discussed in reference to this species. As for humans, diagnosis is a combination of clinical manifestations and laboratory data but also must include other considerations.

Diagnosis of Lyme disease may be made by examining:

1) clinical criteria,
2) rule-out diagnoses,
3) results of laboratory testing,
4) response to antibiotic therapy,
5) and epidemiologic and ecologic considerations.

Clinical criteria must first include an abnormality of the target system and other accompanying signs of disease.

Lyme arthritis is the most common sign of disease caused by Borrelia burgdorferi and swollen, painful joints are often present. Even in the absence of visible lesions, there will be lameness of a limb and the patient will exhibit pain on palpation, flexion or extension of the effected joint. Fever, lethargy, inappetence, and lymphadenopathy are frequently present.

In cardiac Lyme disease, high degrees of conduction disturbance have been noted. Neurologic effects of infection have included facial nerve paralysis and seizure disorder. Dogs presenting with renal failure associated with Lyme disease have all of the signs typical of uremia and often demonstrate edema of the limbs.

Rule outs

Rule-out diagnoses must run through the complete gamut of causes for the clinical signs observed in the musculoskeletal system, heart, nervous system, and kidneys.

As in all other diagnostic situations, the veterinarian must consider other causes on a prioritized basis. Often trauma may be easily ruled-in by history or observed injury, whereas other times it may be ruled-out by physical examination and history of a very protected and closely observed lifestyle.

Various alternative diagnoses will have a higher ranking in the differential diagnosis based on regional incidence of diseases and exposure histories. The consideration of some rule-out diagnoses may require specific laboratory testing.

Lab testing

Laboratory testing for antibodies is helpful in establishing if there has been previous exposure to Borrelia burgdorferi but improper interpretation of serology and extreme variability in results confound the issue.

It is essential to stress that a positive ELISA, IFA of western immunoblot is only an indication of prior exposure.

In healthy dogs sero-surveyed in an endemic area 50 percent had positive ELISA results. Reasons for high seroprevalence in the absence of active disease include: long incubation periods for disease, persistence of antibody after treated or spontaneously remitted episodes of illness, poor reliability of laboratory tests, and recently, the growing number of vaccinated dogs which will test positive.

Western immunoblotting has been introduced as an improvement over ELISA or IFA serology, but blots are still only a test for exposure.

When properly interpreted, western blots may help distinguish between natural exposure to the live organism by tick bite or exposure by immunization to killed spirochetes or spirochetal antigens.

In dogs exposed to live spirochetes transmitted by ticks there is a notable absence of antibodies directed against the Borrelia outer surface proteins A and B (OspA and OspB) which migrate at molecular weights of 31- and 34 kilodaltons. This absence of immune response is the result of alteration of the surface structure of spirochetes within the vector tick.

During the early period of tick feeding and spirochete multiplication and dissemination to the ticks salivary glands, OspA ceases to be expressed as a spirochete surface antigen. In a study of 27 dogs immunized (with the whole-cell bacterin, LymeVax®) prior to any natural exposure, immunoblots demonstrated antibody response to the antigens in the vaccine and more than a one year time period serial follow-up blots failed to demonstrate conversion to antigens typical of tick exposure.

In the diagnosis of all syndromes of Lyme disease, laboratory tests may be expected to demonstrate abnormalities in effected organ systems.

Renal disease caused by Borrelia burgdorferi will be accompanied by uremia, hyperphosphatemia, and often hypoalbuminemia in the face of the hallmark protein loosing nephropathy.

Dogs with cardiac conduction disturbances will have abnormal ECG. In studies of dogs with Lyme arthritis, CBC, SMAC, immune profiles and serology for exposure to other tick-borne organisms were all negative, while urinalysis was abnormal demonstrating presence of protein, cells and casts suggesting subclinical nephritis in these dogs with clinical joint abnormality. Laboratory tests for rule-out and rule-in diagnoses should be based on the presenting signs.

Treatment

Response to antibiotic therapy in dogs with Lyme arthritis may be dramatic.

Even in dogs that remain chronically or intermittently lame, there is some response to early antibiotic therapy. A complete absence of any response to appropriate antibiotic therapy is a strong indicator that diagnostic efforts should be made to identify a cause other than Lyme disease.

Antibiotics in the penicillin or tetracycline families should be considered as first-line therapeutic drugs in all suspected cases of disease caused by infection with Borrelia burgdorferi.

In one study, drugs in either group were found to be equally effective in dogs with Lyme arthritis. Recent studies done on laboratory Beagles infected by ticks indicate that organisms persist even after adequate antibiotic therapy. This finding suggests that once a dog is infected it may be infected for life and the clinical course of each infection may be decided in large part by host factors rather than by the organism.

Seventy percent of human patients with chronic Lyme disease in one study, completed in both Europe and the United States, had a specific histocompatability marker in common.

In syndromes of canine Lyme disease other than arthritis response to antibiotic therapy may be far less dramatic. Histologic examination of cardiac and renal tissue from dogs with Lyme disease effecting these organs has demonstrated severe pathologic changes which were not reversible.

Epidemiologic factors

Epidemiologic and ecologic considerations play a major role in inclusion of Lyme disease in differential diagnosis.

The epidemiologic and ecologic patterns of Borrelia burgdorferi's spread may differ in different parts of the United States. In the areas of highest incidence (upper Midwest and Northeast) a two-year tick life cycle maintains and transmits the organism very efficiently. High rates of infection in Ixodes scapularis facilitate exposure of domestic animals to the organism because this tick feeds readily on these animals in its nymph and adult stages.

In other areas, life cycles differ. In Southern California nymph Ixodes pacificus often feed on western fence lizards, an intermediate host whose blood serum has a remarkable ability to kill spirochetes in infected ticks. Yet, in northern California studies conducted in the late 1980s demonstrated rates of infection in dogs to be as high as those found in New England.

In laboratory studies done in the Southeast United States where immature Ixodes scapularis parasitize the five line skink, this lizard was found to be capable of maintaining infection of Borrelia burgdorferi and even to competent to transmit that infection to ticks.

The diagnostic dilemma posed by Borrelia burgdorferi induced diseases is multifaceted.

Mimicry of signs caused by many infections, immune mediated and autoimmune diseases, and even physical injury are a major factor.

The lack of a specific and sensitive test for the disease, rather than the infection, confounds the issue.

All clinicians, whether veterinarians or physicians, must make a clinical diagnosis based on presenting signs, rule-out and rule-in of alternate causes, examination of appropriate laboratory data, observation of response to appropriate antibiotic therapy and epidemiologic considerations.

Until a careful consideration of all of these factors has been made, it may be best when asked if a particular set of signs in companion animals may be associated with Lyme disease to say: "possibly" or "I don't have enough information to say at this time" rather than "no."


Testing is not expensive:

Lyme Disease Kinetic ELISA  Canine & Equine 12.00/sample
Lyme Disease PCR  35.00
Lyme Disease Western Blot Canine & Equine 30.00/sample