Two important new studies :-
Variable manifestations, diverse seroreactivity and post-treatment persistence in non-human primates exposed to Borrelia burgdorferi by tick feeding
Abstract
The efficacy and accepted regimen of antibiotic treatment for Lyme disease has been a point of significant contention among physicians and patients. While experimental studies in animals have offered evidence of post-treatment persistence of Borrelia burgdorferi, variations in methodology, detection methods and limitations of the models have led to some uncertainty with respect to translation of these results to human infection. With all stages of clinical Lyme disease having previously been described in nonhuman primates, this animal model was selected in order to most closely mimic human infection and response to treatment. Rhesus macaques were inoculated with B. burgdorferi by tick bite and a portion were treated with recommended doses of doxycycline for 28 days at four months post-inoculation. Signs of infection, clinical pathology, and antibody responses to a set of five antigens were monitored throughout the ~1.2 year study. Persistence of B. burgdorferi was evaluated using xenodiagnosis, bioassays in mice, multiple methods of molecular detection, immunostaining with polyclonal and monoclonal antibodies and an in vivo culture system. Our results demonstrate host-dependent signs of infection and variation in antibody responses. In addition, we observed evidence of persistent, intact, metabolically-active B. burgdorferi after antibiotic treatment of disseminated infection and showed that persistence may not be reflected by maintenance of specific antibody production by the host.
Late Disseminated Lyme Disease: Associated Pathology and Spirochete Persistence Post-Treatment in Rhesus Macaques
Abstract
Non-human primates currently serve as the best experimental model for Lyme disease due to their close genetic homology with humans and demonstration of all three phases of disease following infection with Borreliella (Borrelia) burgdorferi (Bb). We investigated the pathology associated with late disseminated Lyme disease (12 to 13 months following tick inoculation) in doxycycline-treated (28 days; 5mg/kg, oral, 2x/day) and untreated rhesus macaques (Rm). Minimal to moderate lymphoplasmacytic inflammation, with a predilection for perivascular spaces and collagenous tissues, was observed in multiple tissues including the cerebral leptomeninges, brainstem, peripheral nerves from both fore and hind limbs, stifle synovium and perisynovial adipose tissue, urinary bladder, skeletal muscle, myocardium, and visceral pericardium. Indirect immunofluorescence assays (IFA) combining monoclonal (outer surface protein A) and polyclonal antibodies were performed on all tissue sections containing inflammation. Rare morphologically intact spirochetes were observed in the brains of two treated Rm, the heart of one treated Rm, and adjacent to a peripheral nerve of an untreated animal. Borreliaantigen staining of probable spirochete cross-sections was also observed in heart, skeletal muscle, and near peripheral nerves of both treated and untreated animals. These findings support the notion that chronic Lyme disease symptoms can be attributable to residual inflammation in and around tissues that harbor a low burden of persistent host-adapted spirochetes and/or residual antigen.
Various reports of this study give details -
Tulane University announcement -
Study finds Lyme bacteria can survive antibiotic treatment months after infection
Outbreak news Today -
Lyme disease: Borrelia burgdorferi survive 28-day course of antibiotics months after infection, according to study
Lyme Disease.org
New study finds Lyme bacteria survive a 28-day course of antibiotics
An excellent in depth look can also be found here- http://counsellingme.com/VIRAS/Embers.html
No comments:
Post a Comment