Lyme disease is an illness caused by a bacterial organism, Borrelia burgdorferi, which is transmitted to animals and humans through the bite of infected ticks.
The disease has been reported in nearly all US states, but the majority of cases occur in the Northeast (New York, Massachusetts, Connecticut, Rhode Island, and New Jersey).
Although different ticks are carriers depending on the region of the country, hard-bodied ticks are the primary ones. The deer tick (Ixodes scapularis) is primarily responsible for Lyme disease on the East coast and the western black-legged tick (Ixodes pacificus) is primarily responsible for the disease on the West coast. The lone star tick (Amblyomma americanum) is responsible for a Lyme-like disease in the South. It is possible that other ticks and biting insects may rarely transmit the disease.
Hard-bodied ticks are found in grassy areas and in brush, shrubs, and woodland areas even on warm winter days. They are active if the temperature is above about 40-degrees Farenheit. These ticks have a 2-year life cycle with 3 stages: larva, nymph, and adult. Each stage takes a single blood meal and it is during the blood meal that the Lyme organism may be passed to an animal or human. The larva are about the size of a grain of sand, the nymphal stage is about the size of a poppy seed and may be most responsible for transmitting Lyme disease, and the adult ticks are about the size of a sesame seed.
Hard-bodied ticks feed on warm-blooded animals including humans, dogs, cats, rodents, birds, deer, horses, and cows. Dogs and humans appear to be most susceptible to the Lyme organism. Ticks may be carried by birds to new regions and so the Lyme organism is spread from one area to another.
In dogs, joint pain and fever are the most common clinical signs. Other Lyme-associated conditions include loss of appetite, swollen lymph glands, heart problems, kidney failure, nervous system disease, and eye problems.
In humans, more than 50 percent of cases have a characteristic skin rash called erythema migrans, which usually looks like an expanding bull's-eye with alternating light and dark rings. Other symptoms include flu-like signs, muscle pain and arthritis, meningitis, numbness, loss of control of one or both sides of the face (called Bell's palsy), fatigue, and heart, eye, respiratory, and gastrointestinal problems.
In dogs, diagnosis of Lyme disease is difficult. Most tests measure antibody response to being exposed to the Lyme organism, and, therefore, does not prove an active infection only exposure.
In addition, antibody response to the Lyme vaccine is detected by these tests. A newer C6 ELISA test can differentiate between antibodies from natural exposure and antibodies from vaccination, although it is not 100%. Use of blood testing with clinical signs especially in an area with many cases of Lyme disease is often used to make the diagnosis.
Antibiotics are used to treat Lyme disease with doxycycline being the preferred first choice. Other antibiotics can be used if needed. Response to treatment does not necessarily confirm Lyme disease, however. Doxycycline can improve arthritis in some dogs without Lyme disease.
Prevention of Lyme disease is best accomplished by checking for ticks and preventing their attachment. Remember, that not all ticks carry the Lyme organism; it is primarily the hard bodied ticks.
Preventing tick attachment using tick repellants and removing ticks when found is the best way to prevent Lyme disease. The Lyme organism is not spread from the tick to the human or dog until it has been attached for at least 24 to 32 hours or more; therefore, if the tick is removed before this time, the risk of transmission is very low. When removing ticks, exercise caution.
Use a pair of tweezers and grasp the tick by the head or mouthparts right where they attach to the skin. Do not grasp the tick by the body.
Without jerking, pull firmly and steadily outward. Do not twist the tick out or apply petroleum jelly, a hot match, alcohol, or any other irritant to the tick in an attempt to remove it. These methods can actually make things worse.
Place the tick in a jar with alcohol to kill it.
Clean the area of the tick bite with a disinfectant.
If you remove a tick from yourself (or other person) or from your dog, keep it for a while. If clinical signs consistent with Lyme disease develop, take the tick with you to the physician or veterinarian.
There are a couple of vaccines for Lyme disease available in the US; however, their effectiveness in preventing infection is not 100% and there are occasional side-effects. In high Lyme areas, beginning the vaccine in puppies and continuing it through adulthood with tick control may be beneficial. In low Lyme areas, the benefits of vaccination should be weighed against the risk of disease and risk of side effects.
For more information
The Lyme Disease Foundation
The American Lyme Disease Foundation, Inc.
The Lyme Disease Association, Inc.
Lyme Disease Network
Lyme Disease and Related Disorders from Pfizer