In an ironic twist, researchers have found a new way of checking former Lyme disease patients for residual traces of the bacteria that causes the disease - by letting ticks feed on them.
While ticks belonging to the Ixodes genus - such as the deer tick - are known for disseminating the debilitating disease, non-infected ticks are able to detect vestiges of the culprit bacterium, Borrelia burgdorferi, well after traditional medical detection methods are able to do so. Post-treatment Lyme disease syndrome (PTLDS), or the condition where symptoms persist after the microbes are no longer detectable due to treatment, often plagues patients with the trademark aches and pains even after they've completed the requisite course of antibiotics.
The detection technique, known as xenodiagnosis, has previously only been successfully achieved with animal test subjects. As the first study with human participants, 36 volunteers were subjected to bites from lab-bred ticks, with the insects removed after four to six days and tested for evidence of Lyme disease. Several ticks were placed on each volunteer, with some participants testing the process up to thirty times - and going through thirty bites. As you might expect, the most commonly reported symptom of those undertaking the study was skin irritation, with researcher Dr. Adriana Marques of the National Institute of Allergy and Infectious Diseases (NIAID) confirming that "...the most common adverse event experienced by volunteers was mild itching at the site of tick attachment."
Of the 36 volunteers, ten had been diagnosed with PTLDS, and another ten had recently been treated for Lyme disease, still harboring high concentrations of the B. burgdorferi-attacking antibodies. Of the remaining participants, five had erythema migrans - the bullseye-shaped rash that often presents as part of Lyme disease - that had previously been treated, and one had erythema migrans and was being treated at the time of the study. The remaining ten were healthy; and acted as the test's control group.
Of course, as the first study of its kind, xenodiagnosis in humans is still very much a work in progress. The results, while promising, didn't yield concrete enough numbers to be touted as a miracle development just yet. Only two of the patients returned B. burgdorferi-positive results - one PTLDS sufferer and the participant being treated for erythema migrans at the time of the study.
The researchers remain cautiously optimistic about the study, expressing the need for further investigation. "Future studies are necessary to determine the incidence of positive xenodiagnostic results for B. burgdorferi after antibiotic treatment, if these results represent viable organisms or remnants of infection, and whether these results can be related to ongoing symptoms in patients after therapy for Lyme disease," a formal press release noted.
The study is continuing at the National Institutes of Health and the Tufts Medical Center.
