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Easier way to detect Lyme disease may be on horizon

Friday - 4/27/2012, 4:34am  ET

Lyme Disease (Courtesy of CDC)
Lyme disease often shows up with a rash that has a bulls eye. (Courtesy of CDC)

Amy Hunter, wtop.com

WASHINGTON - Lyme disease is expected to be more prevalent this summer because of the warm winter, and while doctors say diagnosing the disease remains difficult, a new product could soon be approved that would allow for earlier, more definitive detection.

"I believe that many people are over-treated for Lyme disease, even though they have not been adequately diagnosed," says Dr. Donald Poretz, a clinical professor of medicine at Georgetown University and past president of the Infectious Disease Society of America.

"That can lead to using antibiotics unnecessarily, which is expensive. People can have bad reactions and the bacteria are becoming resistant to drugs."

The new test, being developed by researchers at George Mason University and Ceres Nanosciences, a diagnostic product development company, would detect the disease in urine samples - sometimes before symptoms appear.

"Our test will say, 'Yes, you still have the infection,' or, 'No, you don't,'" says Ross Dunlap, chief executive officer of Ceres. "With this, you're able to detect things that you were never able to detect before."

Lyme disease, which is carried by ticks, is one of the most rapidly emerging infectious diseases in North America, says the Centers for Disease Control and Prevention.

Ten years ago in Maryland, 688 cases of Lyme disease were diagnosed. By 2009, that number had climbed to 1,466. In Virginia, the number of cases soared from 149 in 2000 to 698 in 2009.

Symptoms include a red rash that expands at the tick bite. This happens to about 75 percent of those affected. The rash can appear anywhere from three to 30 days after infection, but appears on average after seven days. It continues to expand up to 12 inches and has a "bulls-eye" appearance, according to the CDC.

Other symptoms include loss of muscle tone in one or both sides of the face, known as Bell's Palsy, pain and swelling in the joints, fever, fatigue and shooting pains that may interfere with sleep.

Poretz says it's easy to diagnose the disease if a person has been bitten by a deer tick, and then has a fever a few days later. It's more difficult later on if a person has other non-specific symptoms, such as a fever, and has not been recently bitten by a tick.

Currently, the only approved method of diagnosing the disease is by conducting an ELISA test on a blood sample. If that test is positive, then a Western blot test is done, Poretz says. If that is also positive, doctors can diagnose Lyme disease.

These tests measure the antibodies in your blood, which the body produces in response to the disease. The body may not produce antibodies right away, which can lead to a delay in diagnosis.

But Poretz cautions some doctors use a variety of labs to test for the disease, which may employ non-approved tests, leading to false positives.

Dunlap says the urine test that is currently undergoing the first phase of clinical trials will be able to detect the direct presence of the Lyme disease-causing bacterium - providing a more definitive and accurate diagnosis of Lyme disease.

"That's why, so far, the leaders in the field have great support for this type of test," Dunlap says. "There is so much uncertainty about diagnosis, and it preys on a lot of people's paranoia."

Right now, Dunlap says a person might pull five ticks out of their bodies after a hike and then call their doctor requesting antibiotics.

"That's awful," he says. "The overuse of antibiotics is a major issue."

Antibiotics are effective in treating the disease if it's caught early. Another attribute of the urine test, Dunlap says, is patients can find out if they've effectively controlled the disease after an antibiotic regimen.

"We're not recreating the wheel," he says. "We're not changing the way tests are done. We're changing the way we extract [the tested material.]"

Both Dunlap and Poretz stress the trials are only in their initial phases and a lot of work needs to be done to bring this product to the market. While they're optimistic, they say it's too early to make a determination on the efficacy of the test.

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(Copyright 2012 by WTOP. All Rights Reserved.)