What is Lyme Disease(Borreliosis)?History Lyme disease (borreliosis) is an infectious, tick-borne disease first recognized in dogs in 1984. It is caused by Borrelia burgdorferi, a type of bacteria called a 'spirochete.' The common deer tick Ixodes scapularis (formerly called Ixodes dammini) is the primary carrier of B. burgdorferi in the Northeast and upper Midwest. The tick Ixodes pacificus is the primary carrier in the West. Although the disease in Connecticut was first diagnosed in 1975, there is evidence that it has existed in wildlife for many years. Tissue samples taken from a white-footed mouse in Massachusetts in 1894 that have recently undergone DNA testing show that it was infected with Lyme disease. Certain environmental factors have caused Lyme disease to be more prevalent in people in the twentieth century. Before 1900, the habitat in the East and upper Midwest was heavily deforested by early settlers. Deer and their associated ticks were greatly reduced. The reforestation of these areas and the resulting booming white-tailed deer population in these areas are probably a big factor in the increase in the incidence. This coupled with increased awareness and testing capabilities has led to the greatly increased reporting of the disease. Where is Lyme disease found? Despite the fact that people and dogs from all states have been infected with the disease, it is felt that they acquired the disease by traveling to endemic areas.  Life cycle of the deer tick The photo below shows the AMERICAN DOG TICK (Dermacenter variablis) male and female on the left edge of a postage stamp.  Tiny rodents, such as voles, and especially the white-footed mouse, harbor in their bodies thousands of the Borrelia bacteria without getting sick. In the early spring while the white-footed mouse goes about its business, some lucky Ixodes tick larvae (from newly hatched eggs laid late the previous fall) grab onto the mouse and begin to feed on its blood. During this feast, the tick larvae acquire many bacteria from the mouse's fluids. The bacteria think this is just great because they can survive and multiply in the tick's gut just as well as in the mouse's. And, what's even better from the bacteria's point of view, their huge numbers won't kill the tiny ticks either. The bacteria have now gone from the host, a white-footed mouse, to the tick carrier called a vector, and are thriving - a bacterial reproductive bonanza! When winter comes, the tick larvae lie dormant, dreaming of warm-blooded creatures upon which to dine come next spring. Tick larvae like the little white-footed mouse but will settle for you or your dog. The bacteria are doing fine too; they're just going along for the warm ride inside the little mouse. Once the warmer spring temperatures arrive, the six-legged tick larvae matures into the eight-legged nymphal stage. Later in the summer, the nymphs reaches the adult stage. The young adult ticks, still harboring all those bacteria without ill effects, just happen to find themselves riding the legs of a white-tailed deer. Banquet time! After the ticks suck the deer's nutrient-rich blood, they can mate and produce thousands of eggs. The following spring the eggs hatch into a new batch of larvae. So where do you and your dog fit in this chain of bacteria, mouse, tick and deer? Although the tick, during various stages of its life cycle, prefers certain creatures upon which to feed, it is quite willing to belly up to a table where people or dogs are the main course. Regardless of the stage - larvae, nymph or adult Ixodes tick - if these critters carry the bacteria in their bodies, people and dogs can become infected if bitten. Sometimes, but not always, clinical sickness (observable disease) results. What percentage of Ixodes ticks carry the bacteria? That varies according to regions. Research has shown that in endemic areas of the mid-Atlantic and Northeast, nymphal-infected ticks ranged from 25 to 50 percent, and, in north central regions, 10 to 16 percent. It is the tiny nymphal stage that is the most responsible for transmitting the disease.  Transmission For a nymph to transmit B. burgdorferi, it must be attached to the host for at least 48 hours. If a tick dies or is removed within this 48-hour period, transmission of the bacteria will not occur. Even if a tick is a carrier of B. burgdorferi and it attaches to the dog for more than 48 hours, the dog may not contract the disease. In fact, studies show that only around 10% of dogs that are exposed will contract the disease. There is no evidence to suggest that infected dogs pose a risk to other members of the household except as a reservoir of infected ticks. Once a tick has had a full meal, it will detach and not bite another mammal. The risk comes from ticks that have not gotten a complete meal and are detached. They could possibly seek out a human and bite them causing infection. Other types of ticks and insects have been shown to be infected with B. burgdorferi, but they are considered insignificant spreaders of the disease. Symptons Clinical illness usually occurs 2 to 5 months after initial exposure and the likelihood of disease and the severity of the disease seems to vary with the animal's age and immune status. Cats can develop Lyme disease, but it occurs rarely in them, even in endemic areas. Other domestic animals such as horses have contracted Lyme disease, but it does not appear to be a significant problem. Dogs show several different forms of the disease, but by far, the most common symptoms are a fever of between 103 and 105°, shifting leg lameness, swelling in the joints, lethargy, inappetence, and maybe most importantly, response to appropriate antibiotics. Arthritis may be a result of both short- and long-term infections. Most dogs that are promptly diagnosed and treated do not appear to develop arthritis, but a few dogs who do not respond completely to treatment or were not treated will develop progressive degeneration of the infected joints. A few dogs have developed severe progressive renal disease as sequelae to Lyme disease. This severe kidney failure is non-responsive to treatment and death is often the outcome. Fortunately, this form appears to be rare. Usually, dogs will not develop any rash or the circular area of redness around the bite (erythema migrans) which is seen in people. Diagnosis Ten years ago, Lyme disease was often under-diagnosed, but today, the opposite is true. Because of the lack of sensitivity of the blood test, many dogs show positive test results, but are not actually infected with the disease. The standard blood test detects antibodies made by the dog in response to infection with B. burgdorferi. The problem is that many animals are exposed to the organism, but fight the infection off on their own. These animals will have antibodies to B. burgdorferi but not have the disease. As we mentioned earlier, only around 10% of the exposed dogs actually contract the infection. At the same time the antibody test cannot distinguish between a dog that has been vaccinated or naturally exposed to Borrelia. Therefore, in endemic areas, the test alone is not an accurate way to get a diagnosis. However, the test can be used with several other criteria to gain a positive diagnosis. Suspected animals should have a history of tick exposure, compatible clinical signs, and have a rapid response to antibiotic therapy. In fact, clinical signs and rapid response to doxycycline antibiotic therapy is how I make a diagnosis of Lyme disease. A practitioner in a Lyme endemic area will often be able to diagnose the disease on physical exam. Practitioners in areas that have fewer Lyme cases may have to resort to using the blood test and treatment to confirm the diagnosis. If an animal that is suspected of having Lyme disease does not clinically improve within 48 hours of starting antibiotic therapy, assume that it is not Lyme disease and begin to do other diagnostic tests to find the source of the problem. Treatment Treatment for Lyme disease is very straightforward and consists of using either a tetracycline or penicillin-based antibiotic. The two most commonly used are oral Doxycycline or Amoxicillin. A recent study showed that both antibiotics worked equally well. The antibiotics must be given a minimum of 14 days, but 30 days is recommended. However, some preliminary studies show that some animals may not even clear the organism after 30 days and will relapse once the antibiotic is discontinued. In these cases, the animal may have to be on the antibiotic for much longer. It appears that some animals may never completely rid themselves of B. burgdorferi despite aggressive treatment. These animals may suffer from increased degenerative changes in the joints leading to premature arthritis. Despite the fact that some animals may develop chronic infections, the vast majority of infected dogs respond rapidly and satisfactorily to doxycycline treatment. In some animals with severe arthritis, pain killers such as buffered aspirin (Do NOT give your cat aspirin unless prescribed by your veterinarian.) can also be used in addition to antibiotics. The use of steroids in this disease is definitely contraindicated. Prevention Prevention of Lyme disease involves the use of vaccination and tick control programs. Vaccination:There are several whole-cell killed vaccines on the market that are licensed for use in the dog, but total protection of a dog through vaccination is difficult. One reason is that a strain of Borrelia bacteria can mutate into a different strain. Unfortunately, antibodies made in response to one strain of the bacteria will not always be able to kill a different strain. In addition, if an animal is previously infected with the disease the vaccine will not offer any protection. These facts coupled with the relatively long incubation period (up to 5 months) contribute to the failure of some of these vaccines in preventing disease. Some veterinarians have criticized the ineffectiveness of the Lyme vaccines and do not recommend their use. Although many dogs have been vaccinated and treated for Lyme disease, some vaccinated animals contract the disease, but it appears that vaccinated animals are less likely to contract the disease than unvaccinated animals. Vaccinations can be started after 12 weeks of age and it is recommended that two doses be given three weeks apart, then boostered yearly after that. Because of the inherent problems of over-vaccination, it is recommended that only dogs that are exposed to ticks in areas where Lyme disease is a problem be vaccinated. Tick Control:Tick control is probably the most important thing an owner can do to prevent Lyme disease in their pet. Ticks carry many other diseases besides Lyme disease and by preventing them from attaching to your pet, we can prevent all of these diseases. Avoiding areas of high tick infestation during periods when ticks are active is one of the best ways to avoid contact. Using insecticides on the dog that repel ticks is another method. With the advent of once-a-month topical insecticides containing permethrin, tick control has become a lot easier and more effective. Permethrin, which is an ingredient in Bio Spot for Dogs, is a very good repellent, and if the tick attaches itself to the animal it will die within 12 hours preventing the passage of the B. burgdorferi. (Permethrins should NOT be used on cats.) Very few tick collars are effective with the exception of a newer collar that contains Amitraz. Amitraz is an organophosphate that is very effective at repelling and killing ticks, but has little effect on fleas. Often using Bio Spot along with a Preventic Collar gives the best protection. Despite the claims made by many products to be effective against ticks, do not be fooled. Ticks are very tough and hard to kill. Our customers indicate that they have had the best luck with the products containing permethrin, fipronil, or amitraz. Removing a Tick:To remove an attached tick, use a pair of fine-tipped tweezers or special tick removal instruments. These special devices allow one to remove the tick without squeezing the tick body. 
Please do not use your fingers to remove or dispose of the tick. We do not want you in contact with a potentially disease-carrying tick. Do NOT squash the tick with your fingers. The contents of the tick can transmit disease. Once an embedded tick is manually removed, it is not uncommon for a welt and skin reaction to occur. A little hydrocortisone spray will help alleviate the irritation, but it may take a week or more for healing to take place. In some cases, the tick bite may permanently scar leaving a hairless area. This skin irritation is due to the irritating and destructive tick saliva. It is not due to the tick losing its head, literally. Do not be worried about the tick head staying in; it rarely happens. The swelling is due to toxic saliva, not toxic heads. Summary The tick-borne spirochete Borrelia burgdorferi causes Lyme disease. It often creates symptoms of lameness and fever. It is very treatable with antibiotics. There are vaccines available for dogs. The human Lyme disease vaccine has been discontinued. Preventing tick attachment is one of the best ways to control the disease.
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