Low risk of developing Borrelia burgdorferi infection in the south-east of Sweden after being bitten by a Borrelia burgdorferi-infected tick (original) (raw)
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Ticks and Tick-borne Diseases, 2016
Lyme borreliosis (LB) is a common and increasing tick-borne disease in Europe. The risk of acquiring a Borrelia infection after a tick bite is not fully known. Therefore, we investigated the incidence of Borrelia infection after a bite by a Borrelia-infected tick and if the Borrelia load and/or the duration of tick-feeding influenced the risk of infection. During 2008-2009, ticks and blood samples were collected from 1546 tick-bitten persons from Sweden and the Åland Islands, Finland. Follow-up blood samples were taken 3 months after the tick bite. The duration of tick feeding was microscopically estimated and Borrelia was detected and quantified in ticks by real-time PCR. Anti-Borrelia antibodies were detected in sera using ELISA tests and immunoblot. Five percent (78/1546) of the study participants developed Borrelia infection (LB diagnosis and/or seroconversion) after a tick bite (45% bitten by Borrelia-infected ticks and 55% bitten by uninfected ticks). Of these, 33 developed LB (whereof 9 also seroconverted) while 45 participants seroconverted only. Experience of non-specific symptoms was more frequently reported by Borrelia-infected participants compared to uninfected participants. All who seroconverted removed "their" ticks significantly later than those who did not. The Borrelia load in the ticks did not explain the risk of seroconversion. Regional and sex differences in the Borrelia seroprevalence were found. The risk of developing a Borrelia infection after a bite by a Borrelia-infected tick is small but increases with the duration of tick feeding.
Annals of Agricultural and Environmental Medicine
Introduction. During feeding, the tick sucks blood from the host along with the pathogens that are in the blood, simultaneously exchanging its own pathogens with the host. Humans can also be a host. It is important to understand the most typical circumstances in which people might become infected with Borrelia burgdorferi. This knowledge will help to prepare health education programmes aimed at the prevention of Lyme disease and other tick-borne diseases. Objective. The aim of the study was to determine the percentage of ticks infected with Borrelia burgdorferi sensu lato, depending on the circumstances of getting bitten. Materials and method. The research material consisted of ticks acquired from people who had been bitten, and questionnaires completed by these people. 510 ticks were acquired from 257 females and 253 males. Following delivery of a tick for testing, the stage of its development was determined and a molecular assay of Borrelia burgdorferi DNA performed. Results. A positive result of the nested-PCR test was obtained in 78 ticks, which represents 15.30% of all ticks. The infected ticks were collected from male (41 ticks-52.56%) and female subjects (37 ticks-47.44%). The biggest number of infected ticks were collected in autumn (54 ticks-69.23%) and from people who had been into forests (44 ticks-56.41%). Among the people from whom the infected ticks were acquired, the dominating group included persons over 16 years of age (53 persons-67.95%) and children aged 0-5 years (16 persons-20.51%). One in four infected ticks were acquired from the southwestern (20 ticks-25.64%) and eastern regions of Poland (21 ticks-26.92%). Conclusion. Infestation of ticks infected with Lyme disease spirochete in this study proved to be variable and depend on the season, the area of tick attack and the region in Poland. The results of the study clearly show that ticks infected with Borrelia burgdorferi inhabit all regions of Poland. The results are consistent with National Institute of Hygiene data which indicates that Lyme disease cases are recorded in all regions of Poland.
Roczniki Państwowego Zakładu Higieny
Background. Lyme borreliosis is the most frequent tick-borne disease in Europe and North America, and the number of registered cases is on the increase. Frequent presence in the habitats of ticks enhances the risk of tick bites and possible infection with Borrelia burgdorferi spirochetes. Objective. The aim of the study was to assess the risk of B. burgdorferi infection posed to hunters and other individuals exposed to activity-related contact with ticks. Material and methods. The study was carried out in the northern part of the Lublin Province (eastern Poland) and involved 150 individuals exposed to tick bites (110 hunters and 40 individuals exposed to activity-related contact with ticks). The analysis of sera for the presence of B. burgdorferi IgM and IgG antibodies was carried out. All 150 individuals were tested with the ELISA assay, and positive and borderline results of the assay were verified with the Western blot test. All study participants completed a questionnaire, which...
Borrelia burgdorferi sensu lato prevalence in tick populations in Estonia
Parasites & Vectors, 2013
Estonia is located in a unique area of co-distribution of Ixodes ricinus and I. persulcatus, which are the main tick vectors of Borrelia burgdorferi sensu lato. In the last decade, the incidence rate of Lyme borreliosis in Estonia has increased dramatically up to 115.4 per 100,000 in 2012. Here we present the first survey of the presence, the prevalence and genetic characteristics of B. burgdorferi s.l. complex spirochetes in the tick population in Estonia.
Vector-Borne and Zoonotic Diseases, 2007
We conducted a prospective study to estimate the Lyme borreliosis incidence in two rural French departments, Meuse and Puy-de-Dôme. Concurrently, we investigated the prevalence of ticks infected with Borrelia burgdorferi sensu lato (sl) and Anaplasma phagocytophilum. The incidence of Lyme borreliosis decreased from 156 to 109/100,000 inhabitants in Meuse and from 117 to 76/100,000 inhabitants in Puy-de-Dôme in 2004 and 2005, respectively, corresponding to a decrease in the density of Ixodes ricinus nymphs infected with B. burgdorferi sl. During the same period, the density of adult ticks increased. Interestingly, B. valaisiana, a nonpathogenic species, infected adult ticks more often than nymphs. These results confirmed the correlation between the Lyme borreliosis incidence and the density of infected nymphs, a stage preferentially infected with B. afzelii. In contrast, we found a low rate of infection by A. phagocytophilum, ranging from 0% to 0.4% in Puy-de-Dôme and from 0.8% to 1.4% in Meuse, suggesting a low risk for humans.
Longitudinal study of Lyme borreliosis in a high risk population in Switzerland
Parasite (Paris, France), 1998
Orienteers from all parts of Switzerland (n = 416) were included in a longitudinal study for Lyme borreliosis. In spring 1986, the seroprevalence was 28.1%. At the beginning of the study, 84.3% of orienteers reported a history of tick bite, and 3.8% reported a past history of Lyme borreliosis. During the first (spring 1986-autumn 1986), second (autumn 1986-spring 1987) and third (spring 1987-autumn 1987) period, rates of seroconversion were 0.6%, 2.7% and 2.1% respectively. During the first and second period, clinical incidence were 1.0% and 0.25% respectively. No active Lyme borreliosis was detected during the third period. Among orienteers who seroconverted during the study (n = 16), only two developed clinical symptoms. Hence, Borrelia burgdorferi infection is often asymptomatic.
PLoS ONE, 2013
The incidence of Lyme borreliosis (LB) in a region may reflect the prevalence of Borrelia in the tick population. Our aim was to investigate if regions with different LB incidences can be distinguished by studying the prevalence and diversity of Borrelia species in their respective tick populations. The Borrelia load in a feeding tick increases with the duration of feeding, which may facilitate a transmission of Borrelia Spirochetes from tick to host. Therefore, we also wanted to investigate how the Borrelia load in ticks that have fed on humans varies with the duration of tick feeding. During 2008 and 2009, ticks that had bitten humans were collected from four regions of Sweden and Finland, regions with expected differences in LB incidence. The duration of tick feeding was estimated and Borrelia were detected and quantified by a quantitative PCR assay followed by species determination. Out of the 2,154 Ixodes ricinus ticks analyzed, 26% were infected with Borrelia and seven species were identified. B. spielmanii was detected for the first time in the regions. The tick populations collected from the four regions exhibited only minor differences in both prevalence and diversity of Borrelia species, indicating that these variables alone cannot explain the regions' different LB incidences. The number of Borrelia cells in the infected ticks ranged from fewer than ten to more than a million. We also found a lower number of Borrelia cells in adult female ticks that had fed for more than 36 hours, compared to the number of Borrelia cells found in adult female ticks that had fed for less than 36 hours.
Prevalence and Diversity of Borrelia Species in Ticks That Have Bitten Humans in Sweden
Journal of clinical …, 2010
Members of the genus Borrelia are among the most common infectious agents causing tick-borne disease in humans worldwide. Here, we developed a Light Upon eXtension (LUX) real-time PCR assay that can detect and quantify Borrelia species in ticks that have fed on humans, and we applied the assay to 399 such ticks. Borrelia PCR-positive ticks were identified to species level by sequencing the products of conventional PCR performed using Borrelia group-specific primers. There was a 19% prevalence of Borrelia spp. in the detached ticks, and the number of spirochetes per Borrelia PCR-positive tick ranged from 2.0 ؋ 10 2 to 4.9 ؋ 10 5 , with a median of 7.8 ؋ 10 3 spirochetes. Adult ticks had a significantly larger number of spirochetes, with a median of 8.4 ؋ 10 4 compared to the median of nymphs of 4.4 ؋ 10 4. Adult ticks also exhibited a higher prevalence of Borrelia (33%) than nymphs (14%). Among the identified species, Borrelia afzelii was found to predominate (61%) and was followed by B. garinii (23%), B. valaisiana (13%), B. burgdorferi sensu stricto (1%), B. lusitaniae (1%), and B. miyamotoi-like (1%). Also, 3% of the ticks were coinfected with multiple strains of B. afzelii. Notably, this is the first report of B. lusitaniae being detected in ticks in Sweden. Our LUX real-time PCR assay proved to be more sensitive than a corresponding TaqMan assay. In conclusion, the novel LUX real-time PCR method is a rapid and sensitive tool for detection and quantification of Borrelia spp. in ticks.
European journal of epidemiology, 2001
The prevalence of different genospecies of Borrelia burgdorferi sensu lato in infected ticks could be a determinant for the risk of acquiring Lyme borreliosis (LB) and its clinical presentation. A total of 7373 ticks and 2761 samples from LB patients from the same area in southwest Germany were analyzed by PCR to assess the frequency of the occurrence of LB-associated genospecies. Fifteen percent of the tick samples and 19% of the human samples were found positive for the presence of B. burgdorferi sensu lato. Further identification of 1106 B. burgdorferi sensu lato positive tick samples by reverse line blotting and 125 positive patient samples by nested PCR using species-specific primers revealed the occurrence of B. afzelii, B. burgdorferi sensu stricto, B. garinii and B. valaisiana. Both single-species and mixed infections were noted and a similar distribution of the different genospecies was found in ticks compared with human samples. It was also the purpose of this study to obt...