CHRONIC LYME-DISEASE IN THE RHESUS-MONKEY

BACKGROUND: We have previously reported the clinical, pathologic, and immunologic features of ''early'' Borrelia burgdorferi infection in rh esus monkeys (3). We have now evaluated these features during the chro nic phase of Lyme disease in this animal model. EXPERIMENTAL DESIGN: C linical signs, and pathologic changes at the gross and microscopic lev els, were investigated 6 months post-infection in several organ system s of five rhesus macaques (Macaca mulatta), which were infected with B orrelia burgdorferi by allowing infected Ixodes scapularis nymphal tic ks to feed on them. A sixth animal was used as an uninfected control. Borrelia antigens recognized by serum antibody were identified longitu dinally by Western blot analysis, and C1q-binding immune complexes wer e quantified. Localization of the spirochete in the tissues was achiev ed by immunohistochemistry and in vitro culture. The species of spiroc heta cultured was confirmed by the polymerase chain reaction. RESULTS: Chronic arthritis was observed in five out of five animals. The knee and elbow joints were the most consistently affected. Articular cartil age necrosis and/or degenerative arthropathy were the most severe join t structural changes, Synovial cell hyperplasia and a mononuclear/lymp hocyte infiltrate were commonly seen. Nerve lesions were also observed , including nerve sheath fibrosis and focal demyelinization of the spi nal cord. Peripheral neuropathy was observed in five out of five anima ls and could be correlated in the most severely affected monkey with t he presence of higher levels of circulating immune complexes. Differen ces in disease severity did not correlate with differences in the anti gens recognized on Western blot analysis. CONCLUSIONS: B. burgdorferi infection in rhesus macaques mirrors several aspects of both the early and chronic phases of the disease in humans. This animal model will f acilitate the study of the pathogenesis of Lyme arthritis and neurobor reliosis.