Tick test for persistent Lyme disease tried in humans

NEW YORK Fri Feb 28, 2014 11:29am EST

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NEW YORK (Reuters Health) - A small experiment to see whether uninfected ticks could "diagnose" a lingering Lyme infection in people produced modest results, researchers say.

DNA from the Lyme parasite, but not live parasites themselves, were transmitted to the ticks from just two people out of two dozen who had persistent Lyme symptoms despite treatment.

In animal studies, researchers have successfully used "xenodiagnosis," or diagnosis with another animal, to detect the signs of a persistent Lyme infection in the blood. The technique has also worked in people to detect another parasitic infection, Chagas disease.

But the new report, published in Clinical Infectious Diseases, describes the first attempt to use xenodiagnosis for Lyme disease.

"This is a very initial study, our main objective was to develop the technique in humans," lead author Dr. Adriana Marques of the National Institutes of Health in Bethesda, Maryland, told Reuters Health.

"It is very hard to find evidence of the bacteria itself, not just antibodies, in infected people once the skin rash is gone," she said. This tick method may make that process a bit easier, but only with further research, she said.

For most people who contract Lyme disease, a couple of weeks of antibiotics clear up the infection easily. About four weeks later, patients with no signs of the infecting bacteria in their blood get a clean bill of health.

But 10 to 20 percent of people who get Lyme disease, which is transmitted through a bite from an infected tick, continue to report having pain, fatigue or aches even when it appears the infection is gone.

The symptoms can last for more than six months and are called Post-Treatment Lyme Disease Syndrome(PTLDS).

In animal tests, mice and monkeys have been infected with Lyme disease then treated until no Lyme bacteria were detectable in their blood. If at that point an uninfected tick bit the animal and Lyme bacteria turned up in the tick, it meant the animal was actually still carrying the infection.

For the new study, researchers tried out the second-bite system on people with PTLDS. Of the 36 participants, 26 had either persistent symptoms after Lyme disease treatment, or still had an itchy, red lesion at the site of the original bite, or had unusually high levels of antibodies against the infection even though treatment seemed to have been successful.

The other ten volunteers were healthy and had never had Lyme disease.

Researchers placed 25 to 30 uninfected ticks on the arm of each person to feed, under a special dressing, and collected the ticks a few days later.

The ticks were then incubated for up to two weeks to allow any potentially transmitted Lyme bacteria to develop, and afterwards researchers did a variety of molecular tests looking for any sings of the bacteria.

None of the ticks from healthy volunteers had evidence of the Lyme bacteria. Researchers successfully harvested usable ticks from 23 participants with a history of Lyme, and 21 had no ticks test positive for signs of bacteria.

For another two people the results were unclear. For one person with persistent symptoms after antibiotic treatment and one person with a persistent rash who had just started antibiotics, the ticks did test positive for fragments of DNA from the bacterium.

"The next step will be to see if the results correlate with persistent symptoms. We can't answer that question right now," Marques said. Right now it doesn't mean anything for the patients' health one way or the other that bacterial DNA was present.

The main objective of the study was to see if this type of xenodiagnosis is safe and appropriate for humans, and the answer seems to be yes since the major complaint from subjects was mild itching, said Justin D. Radolf of the University of Connecticut Health Center in Farmington.

"But the results don't change our understanding of PTLDS," said Radolf, who wrote an editorial accompanying the study.

"There is consensus that post-Lyme disease syndrome as defined in the paper does exist and that it occurs in a minority of people," said Linda K. Bockenstedt of Yale University School of Medicine in New Haven, Connecticut, who coauthored the editorial. "We do not know why this occurs, and the reasons may not be the same for everyone."

The subject is controversial because "chronic Lyme disease" can describe a number of conditions and a constellation of symptoms in people who may never actually have been infected with the bacteria.

"Many chronic Lyme disease patients have been assigned the diagnosis based on symptoms only (not objective signs), and through either misinterpretation of appropriately conducted Lyme (blood tests) or the use of nonvalidated tests," Bockenstedt told Reuters Health in an email.

That could mean that "chronic Lyme disease" is being used as a catchall when in fact another medical condition might underlie the symptoms.

It's hard to say how useful this technique actually is in humans for Lyme disease, Bockenstedt and Radolf write in the journal. The only way to diagnose a persistent infection is by finding live bacteria, which this test did not.

SOURCE: bit.ly/1cPZLio Clinical Infectious Diseases, online February 11, 2014.

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Comments (5)
garrity wrote:
As an ID physician, I appreciate that the author kept to the scientific consensus on Lyme, rather than getting distracted by the massive quantity of misinformation found on the Internet. Unfortunately, experience suggests that shortly the author will be flamed by the passionate but ultimately misinformed “Lyme lobby.” Thanks to the author, from someone who treats actual Lyme infections for a living.

Feb 28, 2014 3:03pm EST  --  Report as abuse
It is all laudable and nice and dandy to hunt for ‘persistent Lyme disease’, but it is also known that Lyme-disease carrying ticks often are vector to co-infections like Babesiosis and mono/toxo-plasmosis. None of these co-infections would show up in regular (ELISA) Lyme-disease screenings, but they are similar and no less unpleasant.
Worse, they do not generally respond (sufficiently) to the standard antibiotic Lyme-Disease treatment and would therefore continue to invade and colonize the infected body.
A more determined focus on, and wider application of a broader spectrum based screening, diagnosis and henceforth treatment would IMHO be more helpful to the infected patient.
That said, a similar approach as described in the article could be easily combined with broader spectrum disease screening and would thus add to the medical arsenal of screening measures.
The idea of being voluntarily subjected to diagnostic ticks, however gives me serious willies.

Feb 28, 2014 3:04pm EST  --  Report as abuse
“Many chronic Lyme disease patients have been assigned the diagnosis based on symptoms only (not objective signs), and through either misinterpretation of appropriately conducted Lyme (blood tests) or the use of nonvalidated tests,” Bockenstedt told Reuters Health in an email.

******Most of the people I know with chronic lyme were CDC positive. I cant even count on one hand the ones that weren’t. What nonvalidated tests is Dr. Bockenstedt talking about – the ones at IGenex that Medicaid pays for – Enough of that nonsense.

There is consensus that post-Lyme disease syndrome as defined in the paper does exist and that it occurs in a minority of people,” said Linda K. Bockenstedt of Yale University School of Medicine in New Haven, Connecticut, who coauthored the editorial. “We do not know
why this occurs, and the reasons may not be the same for everyone.”

*****How about the bacteria drives the immune system down so low that any other infection transmitted during exposure complicates the picture and any virus dormant in the body is able to go rampant in the body.

Controversy only continues to exist when one of the parties will not allow truth in studies to come out and are willing to admit that controversy will not solve the problem. Thank God for the doctors who are sticking up for these patients in spite of the fact that their livelihood and careers are put in jeopardy. Do you think they are doing this for money – please no money is worth the ridicule and harassment they suffer not to mention the complexity of treating someone with this horrible condition.

The only way to diagnose a persistent infection is by finding live bacteria, which this test did not.

****Borrelia sequesters itself in lymph nodes and in tissues, organs, bones and brain – not likely to hang out in the blood – it is afterall one of the most sophiscated bacteria.

Feb 28, 2014 3:46pm EST  --  Report as abuse
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