[Investigation of Lyme disease in northeast of China].

In 1987-1988, we conducted investigation of Lyme disease in Northeast of China. The disease was widespread in the forest areas of Heilonjiang and Jilin provinces where Ixodes persulcatus population thrives. The disease occurred at Daqing tree farm where 628 people were inquired and examined among them, 37 cases including 23 cases of ECM, 6 cases of neurological abnormalities, 7 cases of arthritis and 1 case of acrodermatitis chronica atrophicans were confirmed being Lyme disease. The sera of patients suspected with the disease and that of the residents at Xiaobai tree farm were tested for antibodies against Borrelia burgdorferi (B31) by ELISA. Seventeen out of 22 patients were positive and 54 out of 240 residents had significant IgG titers. Samples of tick midgut were inoculated into BSK medium and cultivated. Three isolates of spirochetes were cultivated from Ixodes persulcatus. One of them (M7) was confirmed being Borrelia burgdorferi. Recently another isolate was cultivated from a patient with ECM.