Lyme borreliosis, an infection caused by the tick-borne spirocheteBorrelia burgdorferi, is a major health problem for populations in areas of endemicity in the Northern Hemisphere. In the present study we assessed the density of ticks and the prevalence ofB. burgdorferi sensu lato among ticks in popular urban recreational areas of Helsinki, Finland. Altogether 1,688 Ixodes ricinus ticks were collected from five areas located within 5 km of the downtown section of Helsinki, and 726 of them (303 nymphs, 189 females, and 234 males) were randomly chosen for laboratory analysis. The midguts of the ticks were divided into three pieces, one for dark-field microscopy, one for cultivation in BSK-II medium, and one for PCR analysis. Ticks were found in all the study areas; their densities varied from 1 to 36 per 100 m along which a cloth was dragged. The rate of tick infection with B. burgdorferi sensu lato varied from 19 to 55%, with the average being 32%. Borellia afzelii was the most predominant genospecies in all the areas, and no B. burgdorferi sensu stricto isolates were detected. Only two ticks were concurrently infected with both B. afzelii and Borrelia garinii. Dark-field microscopy gave more positive results for B. burgdorferi than did cultivation or PCR analysis. However, the agreement between all three methods was fairly good. We conclude that Lyme borreliosis can be contracted even in urban environments not populated with large mammals like deer or elk. The disease should be taken into account in the differential diagnosis of certain symptoms of patients from these areas, and the use of measures to improve the awareness of the general population and health care officials of the risk of contracting the disease is warranted.

The purpose of the studies was to determine the prevalence of Borrelia burgdorferi sensu lato in selected populations of Ixodes ricinus in Finland and to secure strains of the spirochete for further characterization. 1,210 Ixodes ricinus ticks (399 females, 419 males and 392 nymphs) were collected during June to August 1992 by flagging from 8 sites in 3 regions. The frequency of B. burgdorferi infection was determined by isolation in BSK II medium. The species identity of most of the isolates was confirmed with the immunofluorescence method. 67 B. burgdorferi strains were isolated from 8 sites; the prevalence ranged from 2.8% to 7.9%. The overall isolation percentage for adult male ticks was 6.4% (7.5% for females, 5.3% for males); for nymphs, 3.8%. No statistically significant association of the prevalence was observed with either pasture or off-pasture habitats nor with specific geographic region/regions. Prevalence figures were roughly of the same magnitude in areas and parts of the country known to differ in their incidence of human borreliosis. An additional 294 ticks, mainly engorged females, were collected from places outside the main study sites. Of the 7 positive ticks 3 were engorged females, originating from a cow, a dog and a cat, respectively. The results in general demonstrate that tick populations in various parts of Finland quite commonly harbour B. burgdorferi.

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Fourteen dogs with pancreatic degenerative atrophy (PDA) were fed their original diets or a special diet for 2 periods of 4 weeks to compare the severety of clinical signs in relat ion to different types of diet. During the first period , the dogs were given ordinary food, and in the second period , the dogs were given only the special diet that consisted of a commercial moderate-fat, low-fiber, highly-digestible food. In addition, equal amounts of pancreatic enzymes were added into the food during both periods . The owners were given a questionnaire covering 9 typical signs of PDA . They were asked to assess the severity of signs daily for the 2 periods using a scale provided with the questionnaire.The general well-being of the dogs was significantly (p < 0.05) better during the period when the dogs were fed a special diet. Of the individual clinical signs associated with PDA the severity of flatulence. borborygmi , volume of faeces and frequency of defecation were significantly (p < 0.05) decreased on the special diet.There were no significant differences in appetite, drinking. colour and consistenc y of the faeces or in coprophagy between the 2 feeding periods . The costs of the special diet were almost double compared to the ordinary diets.

Thirty-seven Borrelia burgdorferi strains, isolated in 1992 from Ixodes ricinus in Finland, were investigated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and by immunoblotting and indirect immunofluorescence assay (IFA) with five to nine monoclonal antibodies (MAbs). By SDS-PAGE results and reactivities to MAbs H3TS, J 8.3, I 17.3, and D6, the 37 isolates were assigned to the species B. burgdorferi sensu stricto (n ‫؍‬ 7), Borrelia afzelii (n ‫؍‬ 17), or Borrelia garinii (n ‫؍‬ 13). Twenty more isolates examined only by IFA and with part of the MAbs were distributed as follows: 9 B. burgdorferi sensu stricto and 11 other species. Among 16 of 37 isolates displaying a SDS-PAGE patterns considered typical of that of B. garinii, 3 were negative by the test with MAb D6; the rest were positive. The three MAb D6-negative isolates reacted with MAb J 8.3 but not with MAb I 17.3. It is suggested that these isolates of a previously undescribed type represent atypical B. afzelii strains deficient in the expression of OspB proteins. The misleading species designation by the SDS-PAGE result is described. The IFA results were generally consistent with those obtained by immunoblotting. The exception was for 3 of 29 isolates that were positive with MAb H5332 by immunoblotting but that were IFA negative. In the present material of 57 strains, all 16 B. burgdorferi sensu stricto isolates originated from the Åland Islands. B. afzelii and B. garinii were isolated from all three regions where ticks were collected. The distributive difference seems to offer a basis for comparative clinico-epidemiological studies of Lyme borreliosis.