Lyme disease is an infection caused by bacteria belonging to Borrelia species. This disease can bring about abnormalities in the joints, the skin, the heart and the nervous system. A recent study has shown that once infected with a particular strain of the Borrelia bacteria, humans can develop immunity against that strain that can last for six to nine years.
What is Lyme Disease?
Lyme disease is a medical illness caused by bacteria belonging to Borrelia species such as Borrelia burgdorferi or Borrelia afzelii. These bacteria are transmitted by deer, who harbour the bacterium in their stomachs. Lyme disease can be spread by these ticks when they bite the skin, so that the bacterium can gain access into the body thereafter. The infected person cannot transmit Lyme disease to other people. Further health problems can develop after infection, such as those pertaining to the skin, the heart, the joints and the nervous system. There may be various degrees of progression that may differ from person to person.
After the initial tick bite in the skin, there may be an expanding reddish rash in the skin that may result. This rash may be accompanied by flu-like symptoms. It can then spread to other parts of the body such as the heart, the nervous system and the joints.
There are three phases of Lyme disease. The first phase consists of an early localized disease with skin inflammation. The second phase consists of early disseminated disease with heart and nervous system involvement. This second phase may bring about palsies and meningitis. The third phase is termed as the late disease with motor and sensory damage and brain inflammation along with arthritis.
During the first phase which is the time within days to weeks after the tick bite, the skin develops expanding redness with a central clearing, termed as a “bull’s-eye” appearance. The spreading rash is termed as “erythema migrans” (formerly called erythema chronicum migrans). However in one out of four patients, there may be no rash. The skin manifestations in the first phase of the disease may be accompanied by generalized fatigue, joint stiffness, muscle stiffness headache and swollen lymph nodes.
After about a month, the redness resolves, even without treatment. After several months after the initial skin redness, the bacteria may spread to other parts of the body, and may bring about diseases in the heart, joints and nervous system. In the later phase of the disease there may be effects in the heart such as inflammation of the heart muscle. This can further result to abnormal heart rhythms and heart failure. Effects on the nervous system may bring about facial muscle paralysis (Bell’s palsy), abnormal sensation due to disease of peripheral nerves (peripheral neuropathy), meningitis, and confusion. Inflammatory arthritis may also result in the form of joint swelling, pain and stiffness. The joints affected are usually the knees.
People with Lyme disease can also develop anxiety and depression. Doctors usually diagnose Lyme disease by finding the classic red rash described above. The patient's medical history may also be obtained. Other diseases should be ruled out such as those affecting the joints, heart, and nervous system. Blood tests may be done to help confirm the diagnosis. Antibodies against the bacteria can be screened using a laboratory method called enzyme-linked immunosorbent assay [ELISA]. Antibiotics are usually given by the doctor to treat the infection.
Lyme Disease Immunity
A recent study done by researchers from the University of Pennsylvania have found out that once a person is infected with a particular strain of bacteria, they can develop immunity against that strain for six to nine years. The findings of this study were published in the April issue of Infection and Immunity. The researchers gathered data from 17 patients. They soon found out that strain-specific immunity would need to last a minimum of four years in order to result in the suite of infections that the 17 patients acquired, and that immunity lasts in the range of six to nine years. However, the researchers also claimed that there is likely to be variation in the strength and duration of immunity among people and perhaps even among strains of the Lyme bacterium.
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