Recent reports of novel hantaviruses in shrews and moles and the detection of rodent-borne hantav... more Recent reports of novel hantaviruses in shrews and moles and the detection of rodent-borne hantaviruses in different rodent species raise important questions about their host range and specificity, evolution, and host adaptation. Tula virus (TULV), a European hantavirus, is believed to be slightly or non-pathogenic in humans and was initially detected in the common vole Microtus arvalis, the East European vole M. levis (formerly rossiaemeridionalis), and subsequently in other Microtus species. Here we report the first multiple RT-PCR detection and sequence analyses of TULV in the Eurasian water vole Arvicola amphibius from different regions in Germany and Switzerland. Additional novel TULV S-, M-, and L-segment sequences were obtained from M. arvalis and M. agrestis trapped in Germany at sites close to trapping sites of TULV-RT-PCR-positive water voles. Serological investigations using a recombinant TULV nucleocapsid protein revealed the presence of TULV-reactive antibodies in RT-PCR-positive and a few RT-PCR-negative water voles. Phylogenetic analyses revealed a geographical clustering of the novel S-, M-, and L-segment sequences from A. amphibius with those of M. arvalis-and M. agrestis-derived TULV lineages, and may suggest multiple TULV spillover or a potential host switch to A. amphibius. Future longitudinal studies of sympatric Microtus and Arvicola populations and experimental infection studies have to prove the potential of A. amphibius as an additional TULV reservoir host.
Tick-borne diseases are an important problem in European countries. In this chapter, we review th... more Tick-borne diseases are an important problem in European countries. In this chapter, we review the biology and distribution of five tick-transmitted pathogens in Germany and neighbouring countries Austria and Switzerland. We focus on the bacterial pathogens Rickettsia spp., Anaplasma phagocytophilum and Francisella tularensis, the protozoan parasite Babesia spp. as well as on Eyach virus. The diagnosis of these pathogens is
The identification and molecular epidemiology of norovirus in outbreaks of gastroenteritis were s... more The identification and molecular epidemiology of norovirus in outbreaks of gastroenteritis were studied during a 3-year period in Germany. Specimens (n ؍ 316) from 159 nonbacterial gastroenteritis outbreaks from March 2001 to June 2004 were analyzed for the presence of noroviruses by reverse transcriptase PCR. Outbreaks were most frequent in elderly people's homes and care centers (43%), followed by hospitals (24%). Molecular analyses of strains from 148 outbreaks showed that there were up to 12 genotypes involved in the outbreaks. Genogroup II noroviruses were responsible for 95% of the outbreaks. Cocirculation of more than one strain in the same outbreak and cocirculation of genogroup I and II strains in the same place were observed. Genogroup II4 (Grimsby-like) was the most prevalent strain, accounting for 48% and 67% of the outbreaks in 2002 and 2003, respectively. The genogroup IIb (Castell/Suria) genotype was observed in all the years of the study. Epidemiological and molecular data indicated that there was a major shift of the predominant strain that coincided with the appearance of a new variant of genogroup II4 in 2002. By the application of reverse transcriptase PCR, this study has demonstrated the importance and dynamism of noroviruses in Germany.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Larvae of the trombiculid mite Neotrombicula autumnalis were collected at 18 sites in and around ... more Larvae of the trombiculid mite Neotrombicula autumnalis were collected at 18 sites in and around Bonn, Germany, to be screened for infection with Borrelia burgdorferi s.l. by means of PCR. Questing larvae numbering 1380 were derived from the vegetation and 634 feeding ones were removed from 100 trapped micromammals including voles, mice, shrews and hedgehogs. In a laboratory infection experiment, a further 305 host-seeking larvae from the field were transferred onto Borrelia-positive mice and gerbils, and examined for spirochete infection at various intervals after repletion. In three cases borrelial DNA could be amplified from the mites: (1) from a larva feeding on a wild-caught greater white-toothed shrew (Crocidura russula), (2) from a pool of four larvae feeding on a B. garinii-positive laboratory mouse, and (3) from a nymph that had fed on a B. afzelii-positive laboratory gerbil as a larva. In the first case, borrelial species determination by DNA hybridization of the PCR product was only possible with a B. burgdorferi complex-specific probe but not with a species-specific one. In the second case, probing showed the same borrelial genospecies (B. garinii) as the laboratory host had been infected with. In the latter case, however, DNA hybridization demonstrated B. valaisiana while the laboratory host had been infected with B. afzelii. Subsequent DNA sequencing confirmed much higher similarity of the PCR product to B. valaisiana than to B. afzelii indicating an infection of the mite prior to feeding on the laboratory host. The negligible percentage of positive mites found in this study suggests that either the uptake of borrelial cells by feeding trombiculids is an extremely rare event or that ingested spirochetes are rapidly digested. On the other hand, the results imply a possible transstadial and transovarial transmission of borreliae once they are established in their trombiculid host. However, unless the transmission of borreliae to a given host is demonstrated, a final statement on the vector competence of trombiculid mites is not possible.
In order to determine whether European hedgehogs (Erinaceus europaeus and E. roumanicus) play a r... more In order to determine whether European hedgehogs (Erinaceus europaeus and E. roumanicus) play a role in the epidemiological cycle of Borrelia burgdorferi sensu lato in Central Europe and Great Britain, tissue samples of hedgehogs from Germany (n = 211), Austria (n = 4), the Czech Republic (n = 22), and the UK (n = 32) were tested for the presence of these tick-borne pathogens. PCR for amplification of the B. burgdorferi s.l.-specific 5S-23S intergenic spacer region as well as the outer surface protein A (ospA) gene were used. B. burgdorferi s.l. DNA was detected in 35 of the 259 E. europaeus and in 2 of 10 E. roumanicus. B. burgdorferi prevalences in E. europaeus ranged from 0% (UK) to 37.5% (Czech Republic), for E. roumanicus from 0% (Czech Republic) to 50.0% (Austria). Sequencing revealed the occurrence of 3 different B. burgdorferi genospecies in E. europaeus: B. afzelii was the dominant genospecies, followed by B. bavariensis (previously B. garinii OspA serotype 4) and B. spielmanii, the latter was detected for the first time in Hamburg (Germany). B. afzelii and B. bavariensis were also found in E. roumanicus. Our results suggest that hedgehogs modulate the epidemiology of certain species of the B. burgdorferi s.l. complex, potentially affecting the distribution and abundance of individual B. burgdorferi s.l. genospecies in various habitats. We hypothesise that juvenile or individuals with low immune competence in particular, have a high reservoir potential for the 3 genospecies identified here.
Background: Sapovirus (SV) has been reported from many countries as one of the major causes of ga... more Background: Sapovirus (SV) has been reported from many countries as one of the major causes of gastroenteritis in infants, but its importance for a broader age range is not well appreciated. While previous studies in our regional laboratory and other parts of Germany have identified Norovirus (NV) as a major cause of gastroenteritis in Germany, the prevalence of SV has not been recorded. Objectives: To investigate the prevalence of SV in outbreaks of gastroenteritis in Baden-Württemberg, Germany. Study design: Stool specimens from 34 outbreaks of gastroenteritis collected in Baden-Württemberg, Germany in 2002 and 2003, which tested negative for other enteric pathogens were tested for SV by RT-PCR. Positive samples were sequenced and typed using phylogenetic analysis. Results: SV was identified in two of 157 (1.3%) specimens. These two viruses belonged to different genotypes of SV and had a nucleotide similarity of only 57%. Conclusions: SV circulates within the study area, but is not an important cause of gastroenteritis in the area.
Canine babesiosis in Europe is generally caused by Babesia canis canis and Babesia canis rossi. H... more Canine babesiosis in Europe is generally caused by Babesia canis canis and Babesia canis rossi. Here we describe the first two autochthonous cases of Babesia gibsoni (Asian genotype) infection in Germany. Two American pit bull terriers showed clinical and hematologic signs consistent with babesiosis. Polymerase chain reaction (PCR) analysis of the 18S rDNA of blood samples revealed 486 bp fragments. The sequences were 100% identical to each other and 100% identical to Babesia gibsoni (Asian genotype). These results represent the first genetic evidence of Babesia gibsoni (Asian genotype) parasites in dogs in Western Europe.
ABSTRACT Ixodid ticks are the most important vectors of human pathogens and are significant vecto... more ABSTRACT Ixodid ticks are the most important vectors of human pathogens and are significant vectors of animal pathogens in Europe. Evidence is accumulating that several tick species have extended their distributions, related at least in part to climate and habitat changes. With increasing anthropogenic modification of the environment, these distributional modifications are likely to continue, with the likelihood that tick-borne diseases will spread to new areas. We discuss those factors which are involved in the changing distributions of ixodid ticks and provide a list of possible invading species given potential changes in tick habitat.
Entomologia Experimentalis Et Applicata, Feb 1, 2010
ABSTRACT The parasitic wasp Ixodiphagus hookeri Howard (Hymenoptera: Encyrtidae) parasitizes larv... more ABSTRACT The parasitic wasp Ixodiphagus hookeri Howard (Hymenoptera: Encyrtidae) parasitizes larvae and nymphs of a number of tick species worldwide. Ticks themselves are parasitic on vertebrate hosts. To study the specificity and reliability of vertebrate odours used by I. hookeri for host location, we conducted bioassays in a four-chamber olfactometer. Wasps were arrested by carbon dioxide and by odours from roe deer faeces and odours from hair of roe deer and wild boar. Odours from faeces of cattle, rabbit, and field mouse as well as odours from hair of cattle and field mouse had no effect. Odours from faeces of the host tick species Ixodes ricinus L. (Acari: Ixodidae) were attractive only up to a distance of 1 cm. Thus, I. hookeri reacts to general (carbon dioxide) and specific vertebrate odours from wild boar and deer. Examination of freshly shot specimens demonstrates that deer and wild boars are infested with a sufficient number of tick nymphs to tap the full reproductive potential of an I. hookeri female, which makes cues from these mammal species reliable. These results indicate that I. hookeri locates its hosts using specific and reliable mammal odours and that ticks are parasitized on their vertebrate hosts. The implications of this host-finding strategy and its benefits for the parasitoid are discussed.
Of 263 patients in Tuscany, Italy, from whom ticks were removed during July 2005-May 2007, fi ve ... more Of 263 patients in Tuscany, Italy, from whom ticks were removed during July 2005-May 2007, fi ve showed signs of tick-borne lymphadenopathy. Of the ticks, 17 were Dermacentor marginatus; 6 (35.3%) of these were identifi ed by sequence analysis as containing Rickettsia slovaca. Tickborne lymphadenopathy occurs in this area. R ickettsia slovaca was fi rst isolated in Czechoslovakia from the tick vector Dermacentor marginatus in 1968 (1) and was subsequently detected in several European countries. It was recognized as the causative agent of tick-borne lymphadenopathy (2-4) and Dermacentor spp.-borne necrosis-erythema-lymphadenopathy (5). Typical clinical signs of infection include skin lesions at the tick bite site and regional, often painful, lymphadenopathy (2,3). Acute disease can be followed by residual alopecia at the bite site (2). This disease is considered a mild rickettsiosis, but severe symptoms have been described, especially in untreated patients (2). D. marginatus is the only member of the species Dermacentor reported in Italy; it is widely distributed in prairies and steppes up to 2,500 m above sea level, including the northern Apennines (6). Adults are active within a temperature range of 4°C to 16°C (7,8). Temperature infl uences the seasonality of tick-borne lymphadenopathy, which has a higher incidence during cold months (4,9). We describe results from a tick-borne zoonoses surveillance system that was implemented in 2002 at the Lucca local health unit (ASL 2) in Tuscany, Italy.
Hantavirus infections are known in Germany since the 1980s. While the overall antibody prevalence... more Hantavirus infections are known in Germany since the 1980s. While the overall antibody prevalence against hantaviruses in the general human population was estimated to be about 1-2%, an average of 100-200 clinical cases are recorded annually. In the years 2005 and 2007 in particular, a large increase of the number of human hantavirus infections in Germany was observed. The most affected regions were located in the federal states of Baden-Wuerttemberg, Bavaria,
Figure S1. Ixodes ricinus nymphal ticks per 100 m2 for 2014. Map of the total number of nymphal t... more Figure S1. Ixodes ricinus nymphal ticks per 100 m2 for 2014. Map of the total number of nymphal ticks monthly flagged during 2014 and interpolated to the entire region of Baden-WĂźrttemberg, Germany. Sampling locations are marked by a circle showing both the observed (left half) and the modelled (right half) tick density.
Figure S3. Time series of monthly Ixodes ricinus nymphal ticks per 100 m2. Selected sites for lan... more Figure S3. Time series of monthly Ixodes ricinus nymphal ticks per 100 m2. Selected sites for land classes C, A, M and B.
International Journal of Health Geographics, Aug 14, 2015
Background: The study describes the estimation of the spatial distribution of questing nymphal ti... more Background: The study describes the estimation of the spatial distribution of questing nymphal tick densities by investigating Ixodes ricinus in Southwest Germany as an example. The production of high-resolution maps of questing tick densities is an important key to quantify the risk of tick-borne diseases. Previous I. ricinus maps were based on quantitative as well as semi-quantitative categorisations of the tick density observed at study sites with different vegetation types or indices, all compiled on local scales. Here, a quantitative approach on the landscape scale is introduced. Methods: During 2 years, 2013 and 2014, host-seeking ticks were collected each month at 25 sampling sites by flagging an area of 100 square meters. All tick stages were identified to species level to select nymphal ticks of I. ricinus, which were used to develop and calibrate Poisson regression models. The environmental variables height above sea level, temperature, relative humidity, saturation deficit and land cover classification were used as explanatory variables. Results: The number of flagged nymphal tick densities range from zero (mountain site) to more than 1,000 nymphs/100 m 2. Calibrating the Poisson regression models with these nymphal densities results in an explained variance of 72 % and a prediction error of 110 nymphs/100 m 2 in 2013. Generally, nymphal densities (maximum 374 nymphs/100 m 2), explained variance (46 %) and prediction error (61 nymphs/100 m 2) were lower in 2014. The models were used to compile high-resolution maps with 0.5 km 2 grid size for the study region of the German federal state Baden-Württemberg. The accuracy of the mapped tick densities was investigated by leave-one-out cross-validation resulting in root-mean-square-errors of 227 nymphs/100 m 2 for 2013 and 104 nymphs/100 m 2 for 2014. Conclusions: The methodology introduced here may be applied to further tick species or extended to other study regions. Finally, the study is a first step towards the spatial estimation of tick-borne diseases in Central Europe.
Recent reports of novel hantaviruses in shrews and moles and the detection of rodent-borne hantav... more Recent reports of novel hantaviruses in shrews and moles and the detection of rodent-borne hantaviruses in different rodent species raise important questions about their host range and specificity, evolution, and host adaptation. Tula virus (TULV), a European hantavirus, is believed to be slightly or non-pathogenic in humans and was initially detected in the common vole Microtus arvalis, the East European vole M. levis (formerly rossiaemeridionalis), and subsequently in other Microtus species. Here we report the first multiple RT-PCR detection and sequence analyses of TULV in the Eurasian water vole Arvicola amphibius from different regions in Germany and Switzerland. Additional novel TULV S-, M-, and L-segment sequences were obtained from M. arvalis and M. agrestis trapped in Germany at sites close to trapping sites of TULV-RT-PCR-positive water voles. Serological investigations using a recombinant TULV nucleocapsid protein revealed the presence of TULV-reactive antibodies in RT-PCR-positive and a few RT-PCR-negative water voles. Phylogenetic analyses revealed a geographical clustering of the novel S-, M-, and L-segment sequences from A. amphibius with those of M. arvalis-and M. agrestis-derived TULV lineages, and may suggest multiple TULV spillover or a potential host switch to A. amphibius. Future longitudinal studies of sympatric Microtus and Arvicola populations and experimental infection studies have to prove the potential of A. amphibius as an additional TULV reservoir host.
Tick-borne diseases are an important problem in European countries. In this chapter, we review th... more Tick-borne diseases are an important problem in European countries. In this chapter, we review the biology and distribution of five tick-transmitted pathogens in Germany and neighbouring countries Austria and Switzerland. We focus on the bacterial pathogens Rickettsia spp., Anaplasma phagocytophilum and Francisella tularensis, the protozoan parasite Babesia spp. as well as on Eyach virus. The diagnosis of these pathogens is
The identification and molecular epidemiology of norovirus in outbreaks of gastroenteritis were s... more The identification and molecular epidemiology of norovirus in outbreaks of gastroenteritis were studied during a 3-year period in Germany. Specimens (n ؍ 316) from 159 nonbacterial gastroenteritis outbreaks from March 2001 to June 2004 were analyzed for the presence of noroviruses by reverse transcriptase PCR. Outbreaks were most frequent in elderly people's homes and care centers (43%), followed by hospitals (24%). Molecular analyses of strains from 148 outbreaks showed that there were up to 12 genotypes involved in the outbreaks. Genogroup II noroviruses were responsible for 95% of the outbreaks. Cocirculation of more than one strain in the same outbreak and cocirculation of genogroup I and II strains in the same place were observed. Genogroup II4 (Grimsby-like) was the most prevalent strain, accounting for 48% and 67% of the outbreaks in 2002 and 2003, respectively. The genogroup IIb (Castell/Suria) genotype was observed in all the years of the study. Epidemiological and molecular data indicated that there was a major shift of the predominant strain that coincided with the appearance of a new variant of genogroup II4 in 2002. By the application of reverse transcriptase PCR, this study has demonstrated the importance and dynamism of noroviruses in Germany.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Larvae of the trombiculid mite Neotrombicula autumnalis were collected at 18 sites in and around ... more Larvae of the trombiculid mite Neotrombicula autumnalis were collected at 18 sites in and around Bonn, Germany, to be screened for infection with Borrelia burgdorferi s.l. by means of PCR. Questing larvae numbering 1380 were derived from the vegetation and 634 feeding ones were removed from 100 trapped micromammals including voles, mice, shrews and hedgehogs. In a laboratory infection experiment, a further 305 host-seeking larvae from the field were transferred onto Borrelia-positive mice and gerbils, and examined for spirochete infection at various intervals after repletion. In three cases borrelial DNA could be amplified from the mites: (1) from a larva feeding on a wild-caught greater white-toothed shrew (Crocidura russula), (2) from a pool of four larvae feeding on a B. garinii-positive laboratory mouse, and (3) from a nymph that had fed on a B. afzelii-positive laboratory gerbil as a larva. In the first case, borrelial species determination by DNA hybridization of the PCR product was only possible with a B. burgdorferi complex-specific probe but not with a species-specific one. In the second case, probing showed the same borrelial genospecies (B. garinii) as the laboratory host had been infected with. In the latter case, however, DNA hybridization demonstrated B. valaisiana while the laboratory host had been infected with B. afzelii. Subsequent DNA sequencing confirmed much higher similarity of the PCR product to B. valaisiana than to B. afzelii indicating an infection of the mite prior to feeding on the laboratory host. The negligible percentage of positive mites found in this study suggests that either the uptake of borrelial cells by feeding trombiculids is an extremely rare event or that ingested spirochetes are rapidly digested. On the other hand, the results imply a possible transstadial and transovarial transmission of borreliae once they are established in their trombiculid host. However, unless the transmission of borreliae to a given host is demonstrated, a final statement on the vector competence of trombiculid mites is not possible.
In order to determine whether European hedgehogs (Erinaceus europaeus and E. roumanicus) play a r... more In order to determine whether European hedgehogs (Erinaceus europaeus and E. roumanicus) play a role in the epidemiological cycle of Borrelia burgdorferi sensu lato in Central Europe and Great Britain, tissue samples of hedgehogs from Germany (n = 211), Austria (n = 4), the Czech Republic (n = 22), and the UK (n = 32) were tested for the presence of these tick-borne pathogens. PCR for amplification of the B. burgdorferi s.l.-specific 5S-23S intergenic spacer region as well as the outer surface protein A (ospA) gene were used. B. burgdorferi s.l. DNA was detected in 35 of the 259 E. europaeus and in 2 of 10 E. roumanicus. B. burgdorferi prevalences in E. europaeus ranged from 0% (UK) to 37.5% (Czech Republic), for E. roumanicus from 0% (Czech Republic) to 50.0% (Austria). Sequencing revealed the occurrence of 3 different B. burgdorferi genospecies in E. europaeus: B. afzelii was the dominant genospecies, followed by B. bavariensis (previously B. garinii OspA serotype 4) and B. spielmanii, the latter was detected for the first time in Hamburg (Germany). B. afzelii and B. bavariensis were also found in E. roumanicus. Our results suggest that hedgehogs modulate the epidemiology of certain species of the B. burgdorferi s.l. complex, potentially affecting the distribution and abundance of individual B. burgdorferi s.l. genospecies in various habitats. We hypothesise that juvenile or individuals with low immune competence in particular, have a high reservoir potential for the 3 genospecies identified here.
Background: Sapovirus (SV) has been reported from many countries as one of the major causes of ga... more Background: Sapovirus (SV) has been reported from many countries as one of the major causes of gastroenteritis in infants, but its importance for a broader age range is not well appreciated. While previous studies in our regional laboratory and other parts of Germany have identified Norovirus (NV) as a major cause of gastroenteritis in Germany, the prevalence of SV has not been recorded. Objectives: To investigate the prevalence of SV in outbreaks of gastroenteritis in Baden-Württemberg, Germany. Study design: Stool specimens from 34 outbreaks of gastroenteritis collected in Baden-Württemberg, Germany in 2002 and 2003, which tested negative for other enteric pathogens were tested for SV by RT-PCR. Positive samples were sequenced and typed using phylogenetic analysis. Results: SV was identified in two of 157 (1.3%) specimens. These two viruses belonged to different genotypes of SV and had a nucleotide similarity of only 57%. Conclusions: SV circulates within the study area, but is not an important cause of gastroenteritis in the area.
Canine babesiosis in Europe is generally caused by Babesia canis canis and Babesia canis rossi. H... more Canine babesiosis in Europe is generally caused by Babesia canis canis and Babesia canis rossi. Here we describe the first two autochthonous cases of Babesia gibsoni (Asian genotype) infection in Germany. Two American pit bull terriers showed clinical and hematologic signs consistent with babesiosis. Polymerase chain reaction (PCR) analysis of the 18S rDNA of blood samples revealed 486 bp fragments. The sequences were 100% identical to each other and 100% identical to Babesia gibsoni (Asian genotype). These results represent the first genetic evidence of Babesia gibsoni (Asian genotype) parasites in dogs in Western Europe.
ABSTRACT Ixodid ticks are the most important vectors of human pathogens and are significant vecto... more ABSTRACT Ixodid ticks are the most important vectors of human pathogens and are significant vectors of animal pathogens in Europe. Evidence is accumulating that several tick species have extended their distributions, related at least in part to climate and habitat changes. With increasing anthropogenic modification of the environment, these distributional modifications are likely to continue, with the likelihood that tick-borne diseases will spread to new areas. We discuss those factors which are involved in the changing distributions of ixodid ticks and provide a list of possible invading species given potential changes in tick habitat.
Entomologia Experimentalis Et Applicata, Feb 1, 2010
ABSTRACT The parasitic wasp Ixodiphagus hookeri Howard (Hymenoptera: Encyrtidae) parasitizes larv... more ABSTRACT The parasitic wasp Ixodiphagus hookeri Howard (Hymenoptera: Encyrtidae) parasitizes larvae and nymphs of a number of tick species worldwide. Ticks themselves are parasitic on vertebrate hosts. To study the specificity and reliability of vertebrate odours used by I. hookeri for host location, we conducted bioassays in a four-chamber olfactometer. Wasps were arrested by carbon dioxide and by odours from roe deer faeces and odours from hair of roe deer and wild boar. Odours from faeces of cattle, rabbit, and field mouse as well as odours from hair of cattle and field mouse had no effect. Odours from faeces of the host tick species Ixodes ricinus L. (Acari: Ixodidae) were attractive only up to a distance of 1 cm. Thus, I. hookeri reacts to general (carbon dioxide) and specific vertebrate odours from wild boar and deer. Examination of freshly shot specimens demonstrates that deer and wild boars are infested with a sufficient number of tick nymphs to tap the full reproductive potential of an I. hookeri female, which makes cues from these mammal species reliable. These results indicate that I. hookeri locates its hosts using specific and reliable mammal odours and that ticks are parasitized on their vertebrate hosts. The implications of this host-finding strategy and its benefits for the parasitoid are discussed.
Of 263 patients in Tuscany, Italy, from whom ticks were removed during July 2005-May 2007, fi ve ... more Of 263 patients in Tuscany, Italy, from whom ticks were removed during July 2005-May 2007, fi ve showed signs of tick-borne lymphadenopathy. Of the ticks, 17 were Dermacentor marginatus; 6 (35.3%) of these were identifi ed by sequence analysis as containing Rickettsia slovaca. Tickborne lymphadenopathy occurs in this area. R ickettsia slovaca was fi rst isolated in Czechoslovakia from the tick vector Dermacentor marginatus in 1968 (1) and was subsequently detected in several European countries. It was recognized as the causative agent of tick-borne lymphadenopathy (2-4) and Dermacentor spp.-borne necrosis-erythema-lymphadenopathy (5). Typical clinical signs of infection include skin lesions at the tick bite site and regional, often painful, lymphadenopathy (2,3). Acute disease can be followed by residual alopecia at the bite site (2). This disease is considered a mild rickettsiosis, but severe symptoms have been described, especially in untreated patients (2). D. marginatus is the only member of the species Dermacentor reported in Italy; it is widely distributed in prairies and steppes up to 2,500 m above sea level, including the northern Apennines (6). Adults are active within a temperature range of 4°C to 16°C (7,8). Temperature infl uences the seasonality of tick-borne lymphadenopathy, which has a higher incidence during cold months (4,9). We describe results from a tick-borne zoonoses surveillance system that was implemented in 2002 at the Lucca local health unit (ASL 2) in Tuscany, Italy.
Hantavirus infections are known in Germany since the 1980s. While the overall antibody prevalence... more Hantavirus infections are known in Germany since the 1980s. While the overall antibody prevalence against hantaviruses in the general human population was estimated to be about 1-2%, an average of 100-200 clinical cases are recorded annually. In the years 2005 and 2007 in particular, a large increase of the number of human hantavirus infections in Germany was observed. The most affected regions were located in the federal states of Baden-Wuerttemberg, Bavaria,
Figure S1. Ixodes ricinus nymphal ticks per 100 m2 for 2014. Map of the total number of nymphal t... more Figure S1. Ixodes ricinus nymphal ticks per 100 m2 for 2014. Map of the total number of nymphal ticks monthly flagged during 2014 and interpolated to the entire region of Baden-WĂźrttemberg, Germany. Sampling locations are marked by a circle showing both the observed (left half) and the modelled (right half) tick density.
Figure S3. Time series of monthly Ixodes ricinus nymphal ticks per 100 m2. Selected sites for lan... more Figure S3. Time series of monthly Ixodes ricinus nymphal ticks per 100 m2. Selected sites for land classes C, A, M and B.
International Journal of Health Geographics, Aug 14, 2015
Background: The study describes the estimation of the spatial distribution of questing nymphal ti... more Background: The study describes the estimation of the spatial distribution of questing nymphal tick densities by investigating Ixodes ricinus in Southwest Germany as an example. The production of high-resolution maps of questing tick densities is an important key to quantify the risk of tick-borne diseases. Previous I. ricinus maps were based on quantitative as well as semi-quantitative categorisations of the tick density observed at study sites with different vegetation types or indices, all compiled on local scales. Here, a quantitative approach on the landscape scale is introduced. Methods: During 2 years, 2013 and 2014, host-seeking ticks were collected each month at 25 sampling sites by flagging an area of 100 square meters. All tick stages were identified to species level to select nymphal ticks of I. ricinus, which were used to develop and calibrate Poisson regression models. The environmental variables height above sea level, temperature, relative humidity, saturation deficit and land cover classification were used as explanatory variables. Results: The number of flagged nymphal tick densities range from zero (mountain site) to more than 1,000 nymphs/100 m 2. Calibrating the Poisson regression models with these nymphal densities results in an explained variance of 72 % and a prediction error of 110 nymphs/100 m 2 in 2013. Generally, nymphal densities (maximum 374 nymphs/100 m 2), explained variance (46 %) and prediction error (61 nymphs/100 m 2) were lower in 2014. The models were used to compile high-resolution maps with 0.5 km 2 grid size for the study region of the German federal state Baden-Württemberg. The accuracy of the mapped tick densities was investigated by leave-one-out cross-validation resulting in root-mean-square-errors of 227 nymphs/100 m 2 for 2013 and 104 nymphs/100 m 2 for 2014. Conclusions: The methodology introduced here may be applied to further tick species or extended to other study regions. Finally, the study is a first step towards the spatial estimation of tick-borne diseases in Central Europe.
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