Histopathological evaluation showed myocarditis in a higher than expected proportion of cases. In one such case, which we studied before the sudden unexpected death occurred, the victim had suffered a Chlamydia pneumoniae infection verified by serology, and a nucleotide sequence was found in the heart and lung by means of the polymerase chain reaction (PCR) that hybridized with a probe specific for that organism. Male Swedish orienteers do not, however, seem to have an increased rate of exposure to this agent. No further sudden unexpected deaths among young orienteers have occurred over the past 3.5 years. At the beginning of that period, attempts were made to modify training habits and attitudes.

cInfections with Bartonella spp. have been recognized as emerging zoonotic diseases in humans. Large knowledge gaps exist, however, relating to reservoirs, vectors, and transmission of these bacteria. We describe identification by culture, PCR, and housekeeping gene sequencing of Bartonella spp. in fed, wingless deer keds (Lipoptena cervi), deer ked pupae, and blood samples collected from moose, Alces alces, sampled within the deer ked distribution range in Norway. Direct sequencing from moose blood sampled in a deer ked-free area also indicated Bartonella infection but at a much lower prevalence. The sequencing data suggested the presence of mixed infections involving two species of Bartonella within the deer ked range, while moose outside the range appeared to be infected with a single species. Bartonella were not detected or cultured from unfed winged deer keds. The results may indicate that long-term bacteremia in the moose represents a reservoir of infection and that L. cervi acts as a vector for the spread of infection of Bartonella spp. Further research is needed to evaluate the role of L. cervi in the transmission of Bartonella to animals and humans and the possible pathogenicity of these bacteria for humans and animals.

Serum samples were collected from healthy blood donors in 5 regions in Sweden in 1999, i.e. from the local Blood Centres (collecting facilities) in Boden, Jönköping, Lund, Skövde, and Uppsala. In total, 498 serum samples (63% males, 37% females) were received and tested by immunofluorescence assay for antibodies against B. elizabethae, B. grahamii, B. henselae (Houston-1), B. henselae (Marseille), B. quintana, and B. vinsonii subsp. vinsonii. An overall Bartonella spp. seroprevalence of 16.1% was found, with a predominance of immunoreactivity to B. elizabethae, at 14.1%; B. grahamii, 2.6%; B. henselae (Houston-1), 1.2%; B. henselae (Marseille), 1.8%; B. quintana, 0.2%; and B. vinsonii subsp. vinsonii, 0.0%. Univariate and multivariate analyses of epidemiological and demographical information revealed an increased rate of B. elizabethae seropositivity in blood donors working outdoors, being out in the wild a minimum of once a week, hunting moose, having cat contact, and travelling to Eastern Europe. Living in the southern region of Sweden (Lund area) was associated with decreased seropositivity to B. elizabethae.

Chlamydia pneumoniae has previously been demonstrated in the atherosclerotic lesions of various arteries, including the coronary arteries, and has been proposed to play a role in the pathogenesis of atherosclerosis. A prospective study of the incidence of C. pneumoniae in the sclerotic valves of patients undergoing aortic valve replacement because of aortic stenosis and in the aortic valves of cases dying of non-cardiac reasons and undergoing forensic autopsy was undertaken. The results were correlated to serological markers of past (IgG) or persistent (IgA) C. pneumoniae infection. C. pneumoniae, as determined by the polymerase chain reaction (PCR), was detected in the aortic valve in 19/39 (49%) patients and in 1/11 (9%) autopsy controls (p = 0.018) and confirmed by electron microscopy in one patient. There was no significant difference in the incidence rate of IgG or IgA antibody positivity between PCR-positive and PCR-negative cardiac patients. These results extend the hypothesis of a pathogenic role of C. pneumoniae in atherosclerosis to include also aortic valve sclerosis.

The use of a 16S rRNA based polymerase chain reaction (PCR) for the detection of Mycoplasma pneumoniae infection was investigated. Sputum samples from 34 patients with respiratory illness and evidence of pneumonia as judged by chest X-ray were analyzed by PCR and microbiological culture. Throat swabs from 14 healthy individuals were used as controls. For serology, an enzyme immunoassay for the detection of immunoglobulin M antibodies and a complement fixation assay were performed. Evidence of Mycoplasma pneumoniae infection was obtained in ten patients (29%), eight of whom were found positive by both PCR and serology. Two of the sputum samples from these eight patients were negative by culture. Of the remaining two patients positive for Mycoplasma pneumoniae, one was positive by PCR and culture but negative by serology, and one was found positive by serology but negative by PCR and culture. Thirteen of the 14 controls were negative by both PCR and serology. One control, however, was negative by serology but positive by PCR, which was probably due to asymptomatic carriage of Mycoplasma pneumoniae. The results of this study indicate the suitability of the PCR for the detection of Mycoplasma pneumoniae in clinical samples as well as its potential value as an additional tool for the diagnosis of infection.