International Journal of Medical Microbiology Supplements最新文献

512 consecutive patients suffering from chronic Lyme borreliosis have been treated according to a standardized therapy regimen which was developed using the results of a controlled trial (Hassler et al., 1990; Hassler, 1992). Follow up was performed for at least 6 (maximum 16) years. In the first two years after initial therapy clinical and serological data were collected every six months including Western blot testing, later once a year.

The roles of two species of rodents: the bank vole (Clethrionomys glareolus) and the yellow-necked mouse (Apodemus flavicollis) in maintaining the vector Ixodes ricinus and Borrelia burgdorferi s.l. were studied. More particularly, seasonal patterns of rodent abundance and infestation rate with I. ricinus ticks as well as the prevalence of B. burgdorferi s.l. and the two species B. garinii and B. afzelii were determined. The studies were carried out in woodlands at Urwitałt near Mikołajki on the Mazury Lakes in 2001.

A total of 196 rodents were trapped and 1349 I. ricinus ticks were collected. There was an increase of rodents in the autumn, with a maximum density of C. glareolus in October and in of A. flavicollis in September. The infestation rate of the investigated animals was above 87% and was dependent on the developmental stage of ticks and host species. Only two stages of I. ricinus were found on trapped rodents: larvae 80% and 84.5%, and nymphs 7.5% and 15.5% for C. glareolus and for A. flavicollis, respectively. The average level of infestation with ticks on rodents appears to be seasonally dependent, and decreases from spring to autumn. Both methods of B. burgdorferi s.l. detection, PCR and IFA, showed that larvae collected from both species of infested rodents were infected by these spirochetes.

An increase in the infection rates with B. burgdorferi s.l. was observed from spring to autumn from 12.5% to 15.6% for larval ticks collected from C. glareolus, and from 5.6% to 8.8% for ticks collected from A. flavicollis. The infection rates of larvae examined by PCR were 5% in the spring and 8% in the autumn for ticks collected from C. glareolus, and 10% and 5% for ticks collected from A. flavicollis. A total number of 329 ticks were analysed for the detection of genospecies (184 for B. garinii and 145 for B. afzelii). In larvae collected from C. glareolus, B. garinii were found in 3% and B. afzelii in 1.1% of assessed ticks. Conversely, in larvae collected from A. flavicollis the percentage of infected ticks was 1.5% for B. garinii and 1.7% for B. afzelii. The examined ear biopsies were Borrelia positive in 2.5% and 4.3% of the 44 bank voles and 80 yellow-necked mice, respectively. Both species of rodents, highly abounded in the Mazury Lakes district od North-Eastern Poland, may represent significant, seasonally dependent, zoonotic reservoirs of B. burgdorferi s.l.

The spirochete Borrelia burgdorferi is transmitted to humans and other warm blooded animals through the bites of infected Ixodes species ticks. Our studies indicate that these spirochetes utilize a quorum sensing mechanism to control protein expression patterns that involves the chemical signal autoinducer-2 (AI-2). Through this mechanism, a population of Lyme disease spirochetes may synchronize production of proteins needed for infection processes. AI-2 is produced by the B. burgdorferi LuxS protein, which we have demonstrated to be a functional enzyme. It has also been previously reported that luxS message is upregulated in feeding nymphal ixodid ticks. Among the B. burgdorferi proteins regulated through AI-2 are the complement inhibitory factor H binding Erp lipoproteins. We now report Erp protein expression is also increased during transmission of B. burgdorferi from nymphal ticks to mammalian hosts. Essentially no B. burgdorferi within unfed nymphal ticks expressed Erps, while almost all transmitted bacteria were Erp positive. These studies suggest that B. burgdorferi within feeding nymphal ticks produce AI-2 to coordinate expression of mammalian infection associated proteins, such as the factor H binding Erp lipoproteins. Binding of mammalian host factor H by Erps may then help promote bacterial dissemination through host tissues.

148 of 157 invited adult subjects who had participated in previous studies were enrolled in this extension study for evaluation of immunogenicity and safety of the second TBE booster immunization. All subjects had been previously immunized in studies with Chiron's formerly marketed TBE vaccine (containing polygeline as the stabilizer) according to the rapid vaccination schedule (i.e. primary immunization on days 0, 7, 21 and first booster immunization at month 15). All subjects were administered the second booster with Chiron's new TBE vaccine, which is free of protein-derived stabilizers, 36 months after the first booster vaccination applied at study month 15. Blood samples were taken prior to booster and 1 month later. In 145 out of 148 subjects, blood samples suitable for measurements of TBE antibodies (ELISA assay) were provided.

Prior to second booster immunization with Chiron's new TBE vaccine, TBE antibodies (GMTs) had remained at a high level and were far above the detection limit of the used ELISA test. All subjects were still seropositive prior to the second booster immunization. The second booster immunization resulted in a further increase of TBE antibodies. The booster vaccination with Chiron's new TBE vaccine was well tolerated by all the vaccinees. Neither febrile post-immunization reactions nor unexpected adverse events or serious adverse events were reported. To summarize, these data clearly show that the TBE vaccination with this new TBE vaccine can be used safely to boost subjects pre-immunized with the former TBE vaccine formulation. Long-lasting immunity following this second TBE booster immunization can be concluded.

The spread of mixed infections with natural focality transmitted by ixodid ticks is a normal phenomenon attributable to trends in the relationships of different pathogens in the vector organism and ecosystem as a whole. Any disease developing as a result of tick bite should be regarded as a potentially mixed infection. Clinically, tick-borne mixed infections proceed more severely than the corresponding diseases caused by a single agent. The residual course of the disease may sometimes be accounted for by the persistence of two or even several pathogens. This implies the necessity of a comprehensive approach to the study, diagnosis, treatment, management and prophylaxis of infections belonging to this group.

Laboratory confirmed cases of tick-borne encephalitis (TBE) have been reported in the Czech Republic since 1971. Peaks of incidence occurred at 2 to 5-year intervals. The incidence in the eighties was generally lower than in seventies. In the nineties there was a sharp increase in incidence that peaked in 1995 (7.2/100,000). TBE cases occur from April to November with maximum incidence in July. During the last decade the second peak of incidence occurred in most years in September and/or October. In the last decade, an extension of the TBE season towards the spring and autumn periods has been observed. In addition to a general increase in TBE incidence in the last decade, some other changes in the epidemiology of TBE were observed in the Czech Republic. During the whole period sex-specific incidence was higher in men than in women (men to women ratio 1.5:1). Age-specific incidence over recent years increased steadily in children and adolescent age groups. In the ten-year age groups from 25 to 65, it remains practically at the same level (6-8/100,000). In older persons it fell to 2-3/100,000.

Tick bites infect patients mainly during their recreational activities. A very small proportion (less than 1%) acquires the infection through the alimentary route. We have tested the hypothesis whether the increase in TBE incidence in the nineties was due to economical or social changes after the velvet revolution of 1989.

Between 1991 and 1995 unemployment largely remained on the same level (between 2–3%). Over the next years the percentage of unemployed persons increased rapidly to 9.3% in 1999 (7.8% in 2001). This trend differs significantly from the trend of TBE incidence that peaked in 1995. No correlation between the district incidence of TBE and the district percentage of unemployment in the years 1997–2001 was found (r=−0.20). The percentage of unemployed persons among the TBE cases was 1–3% in contrast to the Czech Republic figures which were 5–9% for the same period. The gross domestic product in USD per capita increased from $ 2,600 in 1991 to $ 5,000 in 1995. Since then it has varied between $ 4,800 and $ 5,600. This trend, therefore, differs from the trend of TBE incidence as well. Among the TBE cases the percentage of foresters and other persons working in the forests in the years 1997–2001 was 0.5–1%.

The behavioral and socio-economic aspects of TBE cases remained stable despite the political changes which have take place in the Czech Republic since the beginning of the nineties. They are not, therefore, responsible for the increased TBE incidence.

In the industrial areas most polluted by SO₂ in the past in northern Bohemia the sharp increase in TBE incidence seems to be connected with measures aiming to eliminate SO₂ emissions from brown coal power stations.