A past history of clinical Lyme borreliosis and the 6-month incidence of clinical and asymptomatic Lyme borreliosis was studied prospectively in a high-risk population. In the spring, blood samples were drawn from 950 Swiss orienteers, who also answered a questionnaire. IgG antiBorrelia burgdorferi antibodies were detected by ELISA. Positive IgG antibodies were seen in 248 (26.1%), in contrast to 3.9%-6.0% in two groups of controls (n = 101). Of the orienteers, 1.9%-3.1% had a past history of definite or probable clinical Lyme borreliosis. Six months later a second blood sample was obtained from 755 participants, 558 (73.9%) of whom were seronegative initially; 45 (8.1%) had seroconverted from negative to positive. Only 1 (2.2%) developed clinical Lyme borreliosis, Among all participants, the 6-month incidence of clinical Lyme borreliosis was 0.8% (6/755) but was much higher (8.1%) for asymptomatic seroconversion (45/558). In conclusion, positive Lyme serology was common in Swiss orienteers, but clinical disease occurred infrequently.Lyme disease, now often called Lyme borreliosis (LB), may affect the skin, heart, joints, and nervous system [1][2][3][4][5][6]. Neurologic, cardiologic, and rheumatologic manifestations such as meningoencephalitis, neuropathy, atrioventricular nodal block, myocarditis, and arthritis may follow in a few weeks to months after erythema migrans (EM). This skin lesion, although characteristic, is by no means an obligatory sign of LB; it was found in only 41%-61% of patients with the disease [7,8]. Arthritis typically is oligoarticular and recurrent but may become chronic and erosive; it predominantly involves the knee joints [3,9].LB is caused by the bite of ticks infected with the spirochete Borrelia burgdorferi [10,11]. The ticks that can transmit disease are part of the Ixodes ricinus complex. The discovery of the spirochete led to serology as an aid in establishing the diagnosis of LB, especially in the absence of EM [12]. In Europe the disorder seems to have a wide and constant distribution [13]. In contrast, in the United States LB may have been confined to three enzootic areas (northeast coast, midwest, California), but cases appear to be increasing and infection to be spreading to new areas. Recognition may also account for some of the apparent increase. LB has now been reported from 35 states. In Long Island, New York, the incidence ofLB was found to be considerably higher than previously recognized [14].Some patients showed inapparent seroconversion after infection. The estimated ratio of apparent to inapparent infection was 1:1 in a study in Great Island, Massachusetts [8].To assess the usefulness of Lyme serology as a diagnostic tool, it would be important to know not only the sensitivity and specificity of the test but also its predictive value. This would imply knowledge about the prevalence and incidence of clinical LB and the ratio of apparent to inapparent infections in populations where the test is applied.We studied past history of clinical LB and frequency of positiv...

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Three cases of spondylodiscitis caused by viridans streptococci were observed within the course of 1 month. Although streptococci have been reported as the third most frequent cause of spondylodiscitis after staphylococci and gram-negative bacteria, alpha-haemolytic streptococci are rarely seen. The three patients presented with symptoms of low back pain; they felt well and did not have a fever or chills. Laboratory examinations revealed inflammation. Further examinations such as scintigraphy, computed tomography or magnetic resonance imaging were done. Bacteriological diagnosis was established by blood cultures in two cases and by needle biopsy of the disco-vertebral space in one. In one patient endocarditis was also documented. Because the prevalence of endocarditis was found to be higher in our cases of spondylodiscitis due to Streptococcus viridans than for other bacteria, the exclusion of this diagnosis must be pursued aggressively. These observations lead us to question if the spectrum of bacteria causing spondylodiscitis is undergoing a change. an aetiological agent could be isolated in 1168 patients (85.4%): in 48% a staphylococcus, in 28% a gram-negative bacterium and in only 10% a streptococcus. There were two cases of viridans streptococci (0.2%). These two cases together with other single case reports [14-22] account for 15 cases of spondylodiscitis due to alpha-haemolytic streptococci. Differentiation of the organisms to the species level was accomplished in six cases: S. mitis (3), S. sanguis (2) and S. anginosus (1). Although a multitude of organisms, bacterial as well as fungal, causing spondylodiscitis has been reported in recent years, almost all were single cases [23-42]. The unusual observation of three cases of spondylodiscitis due to alpha-haemolytic streptococci within 1 month prompted us to review the clinical and laboratory findings and to compare these cases with those caused by Staphylococcus aureus.

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