Prevalence, Diversity, and Load of Borrelia species in Ticks That Have Fed on Humans in Regions of Sweden and Åland Islands, Finland with Different Lyme Borreliosis Incidences (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.
Microorganisms
In Europe, Ixodes ricinus plays a major role as a vector of Borrelia burgdorferi sensu lato (s.l.) spirochaetes, the causative agents of Lyme borreliosis, among other pathogens. In unfed ticks, Borrelia spirochaetes experience prolonged nutrient restriction. However, only few studies exist with regard to Borrelia infections in unfed ticks of different physiological ages. Changing body dimensions of unfed ticks, due to the consumption of energy reserves, allow physiological age estimation. The present study investigated the relationship of morphometric age with Borrelia prevalence and spirochaete load in 1882 questing I. ricinus nymphs, collected at two different locations in northern Germany in 2020. In addition, Borrelia species composition was investigated by employing a reverse line blot (RLB) probe panel suitable for the detection of ten different B. burgdorferi s.l. species, as well as the relapsing-fever spirochaete B. miyamotoi. Overall, Borrelia prevalence was 25.8% (485/188...
Parasites & vectors, 2017
The population dynamics of vector-borne pathogens inside the arthropod vector can have important consequences for vector-to-host transmission. Tick-borne spirochete bacteria of the Borrelia burgdorferi (sensu lato) species complex cause Lyme borreliosis in humans and spend long periods of time (>12 months) in their Ixodes tick vectors. To date, few studies have investigated the dynamics of Borrelia spirochete populations in unfed Ixodes nymphal ticks. Larval ticks from our laboratory colony of I. ricinus were experimentally infected with B. afzelii, and killed at 1 month and 4 months after the larva-to-nymph moult. The spirochete load was also compared between engorged larval ticks and unfed nymphs (from the same cohort) and between unfed nymphs and unfed adult ticks (from the same cohort). The spirochete load of B. afzelii in each tick was estimated using qPCR. The mean spirochete load in the 1-month-old nymphs (~14,000 spirochetes) was seven times higher than the 4-month-old ny...
Borrelia Diversity and Co-infection with Other Tick Borne Pathogens in Ticks
Frontiers in Cellular and Infection Microbiology, 2017
Identifying Borrelia burgdorferi as the causative agent of Lyme disease in 1981 was a watershed moment in understanding the major impact that tick-borne zoonoses can have on public health worldwide, particularly in Europe and the USA. The medical importance of tick-borne diseases has long since been acknowledged, yet little is known regarding the occurrence of emerging tick-borne pathogens such as Borrelia spp., Anaplasma phagocytophilum, Rickettsia spp., Bartonella spp., "Candidatus Neoehrlichia mikurensis", and tick-borne encephalitis virus in questing ticks in Romania, a gateway into Europe. The objective of our study was to identify the infection and co-infection rates of different Borrelia genospecies along with other tick-borne pathogens in questing ticks collected from three geographically distinct areas in eastern Romania. We collected 557 questing adult and nymph ticks of three different species (534 Ixodes ricinus, 19 Haemaphysalis punctata, and 4 Dermacentor reticulatus) from three areas in Romania. We analyzed ticks individually for the presence of eight different Borrelia genospecies with high-throughput real-time PCR. Ticks with Borrelia were then tested for possible co-infections with A. phagocytophilum, Rickettsia spp., Bartonella spp., "Candidatus Neoehrlichia mikurensis", and tick-borne encephalitis virus. Borrelia spp. was detected in I. ricinus ticks from all sampling areas, with global prevalence rates of 25.8%. All eight Borrelia genospecies were detected in I. ricinus ticks: Borrelia garinii (14.8%), B. afzelii (8.8%), B. valaisiana (5.1%), B. lusitaniae (4.9%), B. miyamotoi (0.9%), B. burgdorferi s.s (0.4%), and B. bissettii (0.2%). Regarding pathogen co-infection 64.5% of infected I. ricinus were positive for more than one pathogen. Associations between different Borrelia genospecies were detected in 9.7% of ticks, and 6.9% of I. ricinus ticks tested positive for co-infection of Borrelia spp. with other tick-borne pathogens. The most common association was between B. garinii and B. afzelii (4.3%), followed by B. garinii and B. lusitaniae (3.0%). The most frequent dual co-infections were between Borrelia spp. and Rickettsia spp., (1.3%), and between Borrelia spp. and "Candidatus Neoehrlichia mikurensis" (1.3%). The diversity of tick-borne pathogens detected in this study and the frequency of co-infections should influence all infection risk evaluations following a tick bite.
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.
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.
Longitudinal surveillance of the tick Ixodes ricinusfor borreliae
Medical and Veterinary Entomology, 2003
Host-seeking Ixodes ricinus (L.) (Acari: Ixodidae) were monitored for borreliae (Borrelia burgdorferi s.l.) using dark-field microscopy in South Moravia (Czech Republic) each May from 1991 to 2001 (150 nymphs, 100 females and 100 males each year). This survey revealed a mean annual percentage of infected ticks of 16.8% (range, 11.7±24.2) in nymphs, 24.9% (range, 16.5±33.6) in females and 26.1% (range, 17.1±37.3) in males. Annual incidence of Lyme borreliosis in humans of the area in the same period (range, 8.7±41.7 per 100 000) correlated significantly with the frequency (number of ticks per flag per hour) of nymphs infected with >50 borreliae or all nymphal ticks, but not with the frequency of females, infected females or the infection rate (% of ticks infected) of either nymphal or female ticks. A prediction of the annual incidence of Lyme borreliosis, based on the frequency of heavily infected or all nymphal I. ricinus ticks, is feasible. The infection rate in I. ricinus correlated significantly with the North Atlantic Oscillation winter index of the last year (in nymphs) or of the year before last (in adults).
Prevalence of Borrelia burgdorferi sensu lato in ticks from the Ternopil region in Ukraine
Journal of Veterinary Research
Introduction Lyme borreliosis/Lyme disease is caused by Borrelia burgdorferi and is one of the most common vector-borne diseases transmitted by ticks. Material and Methods A total of 136 Ixodes ricinus ticks, collected in the Ternopil (Ukraine) region, including 126 adults (70 females and 56 males), and 10 nymphs were examined. The identification of the species and their developmental form was based on morphological characteristics. Results PCR with B5S-Bor and 23S-Bor primers resulted in Borrelia burgdorferi sensu lato DNA amplification among six ticks (4.4%). The detailed analysis based on the DNA sequencing showed the presence of DNA of Borrelia afzelii in four samples; the remaining two represented Borrelia burgdorferi sensu lato complex, although their genospecies were not determined. The research confirmed the dominance of Borrelia afzelii genospecies in the ticks from Ukraine. Conclusion It seems reasonable to undertake similar research in ticks from other regions of Ukraine....
Prevalence rates of Borrelia burgdorferi sensu lato in host-seeking Ixodes ricinus ticks in Europe
Parasitology Research, 1998
Borrelia burgdorferi sensu lato spirochetes have been found in all examined Ixodes ricinus (L.) populations in Europe. The overall mean proportions of unfed I. ricinus infected with B. burgdorferi s.l. were 1.9% (range 0±11%), 10.8% (2±43%) and 17.4% (3± 58%) for larvae (n 5699), nymphs (n 48 804) and adults (n 41 666), respectively. However, the results varied according to the method used. Cultivation in BSK medium is the least sensitive technique (an average of 11% adult ticks found infected), whereas polymerase chain reaction detecting spirochetal DNA is probably the most sensitive method (29% adults found infected). Microscopic methods (dark ®eld, phase contrast, direct or indirect¯uorescence) are generally comparable to each other (17±20% adults found infected) and should be regarded as standard procedures because they also make possible a quantitative estimation of spirochetes in the vector. Some technical problems of these methods are discussed.