CLINICAL-FEATURES OF LYME BORRELIOSIS IN THE MIDDLE URALS AND DISTRIBUTION OF BORRELIA-BURGDORFERI SENSU LATE SPECIES IN LOCAL IXODES-PERSULCATUS TICKS

From 1991 to 1993, we investigated the clinical features of Lyme borre liosis (LB) in 864 patients from the Sverdlovsk region (population 4.5 million) in the middle Urals. Ixodes persulcatus ticks were collected in the vicinity of Yekaterinburg to determine the presence of Borreli a burgdorferi sensu late species. From 1991 to 1993, the number of pat ients with LB increased from 91 to 320 and 453, respectively. Nearly a ll LB patients (97%) recalled a tick bite and the first signs of LB de veloped between May and August. Erythema migrans (EM) was seen in 820 patients (94.9%) and fever was common (44.6%). Neuroborreliosis, mainl y radiculoneuritis, was found in 154 patients (17.8%), secondary eryth ema was seen in 53 patients, and Lyme arthritis (LA) was diagnosed in 35 patients. Carditis was rare and acrodermatitis chronica atrophicans (ACA) was not seen. Only 44 patients developed one or more symptoms o f LB without a preceding EM. Few patients were seropositive for tick-b orne encaphalitis. Borrelial DNA was detected in 67% of I. persulcatus ticks. Infected ticks carried predominantly Borrelia garinii or Borre lia afzelii, mixed infections of both species were common. Borrelia va laisiana was detected once, and B. burgdorferi sensu stricto was not f ound. Although the course of LB in the middle Urals is comparable to t hat of European LB, several discrepancies were noted. LB patients ofte n recall tick bites, fever is common, LA is mild and ACA is absent.