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A possible case of LYME DISEASE
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Clinical Case
A 13 year-old girl named Julia awoke on a Saturday morning with a crooked smile. She found she could not move the right side of her face and it felt stiff. Her grandfather had recently suffered a stroke and could not move the right side of his face either. Julia worried that she also suffered a stroke and her parents called Julia's pediatrician. She suggested Julia go to the emergency room to see what was wrong. There Julia was examined. It was agreed that it was not a stroke, but a condition called Bell's palsy also known as facial nerve paralysis. Because it was early summer in Maine, they wondered if Julia's Bell's palsy was caused by Lyme disease. They asked if Julia had been bitten by a tick, had noticed a rash, or had any aches or pains especially in her joints. Julia answered "no" to these questions but, to be certain, the doctors suggested that Julia have a test for Lyme disease. Blood was drawn and sent to the FBR to rule-out Lyme disease. If Julia had Lyme disease an antibiotic would be needed to treat the infection and prevent long-term consequences. How Lyme disease is evaluated Lyme disease is an infectious disease caused by a spirochete named Borellia burgdorferi which is transferred to humans by the saliva of the deer tick Ixodes. The body mounts a number of defenses to combat the infection. A major part of this defense consists of antibodies manufactured by the body's B-lymphocytes specific for various proteins (antigens) from the spirochete. Using sensitive immune-based assays these antibodies can be measured. One of these testing methods is called an ELISA (enzyme-linked immunosorbent assay). This is the initial screening test for Lyme disease at the FBR. However, this screening test can be positive in the presence of antibodies to antigens from other infections the individual has encountered. Because a "false-positive" result is possible, a positive ELISA needs to be confirmed by a second method called a Western blot. |
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Labs at ScienceWorks for ME Lab exercises offered by ScienceWorks for ME can be used to illustrate the principles behind the screening ELISA test for Lyme disease. To schedule a visit for your biology class, contact by e-mail Links about Lyme disease |
