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Lamsal A, Edgar KS, Jenkins A, Renssen H, Kjaer LJ, Alfsnes K, Bastakoti S, Dieseth M, Klitgaard K, Lindstedt HEH, Paulsen KM, Vikse R, Korslund L, Kjelland V, Stuen S, Kjellander P, Christensson M, Teräväinen M, Jensen LM, Regmi M, Giri D, Marsteen L, Bødker R, Soleng A, Andreassen ÅK. Prevalence of tick-borne encephalitis virus in questing Ixodes ricinus nymphs in southern Scandinavia and the possible influence of meteorological factors. Zoonoses Public Health 2023; 70:473-484. [PMID: 37248739 DOI: 10.1111/zph.13049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/25/2023] [Accepted: 05/06/2023] [Indexed: 05/31/2023]
Abstract
Ixodes ricinus ticks are Scandinavia's main vector for tick-borne encephalitis virus (TBEV), which infects many people annually. The aims of the present study were (i) to obtain information on the TBEV prevalence in host-seeking I. ricinus collected within the Øresund-Kattegat-Skagerrak (ØKS) region, which lies in southern Norway, southern Sweden and Denmark; (ii) to analyse whether there are potential spatial patterns in the TBEV prevalence; and (iii) to understand the relationship between TBEV prevalence and meteorological factors in southern Scandinavia. Tick nymphs were collected in 2016, in southern Scandinavia, and screened for TBEV, using pools of 10 nymphs, with RT real-time PCR, and positive samples were confirmed with pyrosequencing. Spatial autocorrelation and cluster analysis was performed with Global Moran's I and SatScan to test for spatial patterns and potential local clusters of the TBEV pool prevalence at each of the 50 sites. A climatic analysis was made to correlate parameters such as minimum, mean and maximum temperature, relative humidity and saturation deficit with TBEV pool prevalence. The climatic data were acquired from the nearest meteorological stations for 2015 and 2016. This study confirms the presence of TBEV in 12 out of 30 locations in Denmark, where six were from Jutland, three from Zealand and two from Bornholm and Falster counties. In total, five out of nine sites were positive from southern Sweden. TBEV prevalence of 0.7%, 0.5% and 0.5%, in nymphs, was found at three sites along the Oslofjord (two sites) and northern Skåne region (one site), indicating a potential concern for public health. We report an overall estimated TBEV prevalence of 0.1% in questing I. ricinus nymphs in southern Scandinavia with a region-specific prevalence of 0.1% in Denmark, 0.2% in southern Sweden and 0.1% in southeastern Norway. No evidence of a spatial pattern or local clusters was found in the study region. We found a strong correlation between TBEV prevalence in ticks and relative humidity in Sweden and Norway, which might suggest that humidity has a role in maintaining TBEV prevalence in ticks. TBEV is an emerging tick-borne pathogen in southern Scandinavia, and we recommend further studies to understand the TBEV transmission potential with changing climate in Scandinavia.
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Affiliation(s)
- Alaka Lamsal
- Department of Natural Science and Environmental Health, The University of South-Eastern Norway, Bø, Norway
- Department of Virology, Norwegian Institute of Public Health, Oslo, Norway
| | - Kristin Skarsfjord Edgar
- Department of Pest Control, Norwegian Institute of Public Health, Oslo, Norway
- Department of Microbiology, Norwegian Veterinary Institute, Ås, Norway
| | - Andrew Jenkins
- Department of Natural Science and Environmental Health, The University of South-Eastern Norway, Bø, Norway
| | - Hans Renssen
- Department of Natural Science and Environmental Health, The University of South-Eastern Norway, Bø, Norway
| | - Lene Jung Kjaer
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Kristian Alfsnes
- Department of Bacteriology, Norwegian Institute of Public Health, Oslo, Norway
| | - Srijana Bastakoti
- Department of Virology, Norwegian Institute of Public Health, Oslo, Norway
| | - Malene Dieseth
- Department of Virology, Norwegian Institute of Public Health, Oslo, Norway
| | - Kirstine Klitgaard
- Department for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | | | - Katrine M Paulsen
- Department of Virology, Norwegian Institute of Public Health, Oslo, Norway
| | - Rose Vikse
- Department of Virology, Norwegian Institute of Public Health, Oslo, Norway
| | - Lars Korslund
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Vivian Kjelland
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
- Research Unit, Sørlandet Hospital Health Enterprise, Kristiansand, Norway
| | - Snorre Stuen
- Department of Production Animal Clinical Sciences, Section of Small Ruminant Research, Norwegian University of Life Sciences, Sandnes, Norway
| | - Petter Kjellander
- Department of Ecology, Grimsö Wildlife Research Station, Swedish University of Agricultural Sciences, Riddarhyttan, Sweden
| | - Madeleine Christensson
- Department of Ecology, Grimsö Wildlife Research Station, Swedish University of Agricultural Sciences, Riddarhyttan, Sweden
| | - Malin Teräväinen
- Department of Ecology, Grimsö Wildlife Research Station, Swedish University of Agricultural Sciences, Riddarhyttan, Sweden
| | - Laura Mark Jensen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Manoj Regmi
- Department of Data Science, Kristiania University College, Oslo, Norway
| | - Dhiraj Giri
- School of Arts, Kathmandu University, Dhulikhel, Nepal
| | | | - René Bødker
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Arnulf Soleng
- Department of Pest Control, Norwegian Institute of Public Health, Oslo, Norway
| | - Åshild Kristine Andreassen
- Department of Natural Science and Environmental Health, The University of South-Eastern Norway, Bø, Norway
- Department of Virology, Norwegian Institute of Public Health, Oslo, Norway
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Kjær LJ, Klitgaard K, Soleng A, Edgar KS, Lindstedt HEH, Paulsen KM, Andreassen ÅK, Korslund L, Kjelland V, Slettan A, Stuen S, Kjellander P, Christensson M, Teräväinen M, Baum A, Jensen LM, Bødker R. Spatial patterns of pathogen prevalence in questing Ixodes ricinus nymphs in southern Scandinavia, 2016. Sci Rep 2020; 10:19376. [PMID: 33168841 PMCID: PMC7652892 DOI: 10.1038/s41598-020-76334-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 10/27/2020] [Indexed: 12/17/2022] Open
Abstract
Tick-borne pathogens cause diseases in animals and humans, and tick-borne disease incidence is increasing in many parts of the world. There is a need to assess the distribution of tick-borne pathogens and identify potential risk areas. We collected 29,440 tick nymphs from 50 sites in Scandinavia from August to September, 2016. We tested ticks in a real-time PCR chip, screening for 19 vector-associated pathogens. We analysed spatial patterns, mapped the prevalence of each pathogen and used machine learning algorithms and environmental variables to develop predictive prevalence models. All 50 sites had a pool prevalence of at least 33% for one or more pathogens, the most prevalent being Borrelia afzelii, B. garinii, Rickettsia helvetica, Anaplasma phagocytophilum, and Neoehrlichia mikurensis. There were large differences in pathogen prevalence between sites, but we identified only limited geographical clustering. The prevalence models performed poorly, with only models for R. helvetica and N. mikurensis having moderate predictive power (normalized RMSE from 0.74-0.75, R2 from 0.43-0.48). The poor performance of the majority of our prevalence models suggest that the used environmental and climatic variables alone do not explain pathogen prevalence patterns in Scandinavia, although previously the same variables successfully predicted spatial patterns of ticks in the same area.
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Affiliation(s)
- Lene Jung Kjær
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.
| | - Kirstine Klitgaard
- Department for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | - Arnulf Soleng
- Department of Pest Control, Norwegian Institute of Public Health, Oslo, Norway
| | | | | | - Katrine M Paulsen
- Department of Virology, Norwegian Institute of Public Health, Oslo, Norway
- Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | | | - Lars Korslund
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Vivian Kjelland
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
- Research Unit, Sørlandet Hospital Health Enterprise, Kristiansand, Norway
| | - Audun Slettan
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Snorre Stuen
- Department of Production Animal Clinical Sciences, Section of Small Ruminant Research, Norwegian University of Life Sciences, Sandnes, Norway
| | - Petter Kjellander
- Department of Ecology, Grimsö Wildlife Research Station, Swedish University of Agricultural Sciences, Riddarhyttan, Sweden
| | - Madeleine Christensson
- Department of Ecology, Grimsö Wildlife Research Station, Swedish University of Agricultural Sciences, Riddarhyttan, Sweden
| | - Malin Teräväinen
- Department of Ecology, Grimsö Wildlife Research Station, Swedish University of Agricultural Sciences, Riddarhyttan, Sweden
| | - Andreas Baum
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Lyngby, Denmark
| | - Laura Mark Jensen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - René Bødker
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
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Kjær LJ, Klitgaard K, Soleng A, Edgar KS, Lindstedt HEH, Paulsen KM, Andreassen ÅK, Korslund L, Kjelland V, Slettan A, Stuen S, Kjellander P, Christensson M, Teräväinen M, Baum A, Jensen LM, Bødker R. Spatial data of Ixodes ricinus instar abundance and nymph pathogen prevalence, Scandinavia, 2016-2017. Sci Data 2020; 7:238. [PMID: 32678090 PMCID: PMC7366694 DOI: 10.1038/s41597-020-00579-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 06/29/2020] [Indexed: 11/09/2022] Open
Abstract
Ticks carry pathogens that can cause disease in both animals and humans, and there is a need to monitor the distribution and abundance of ticks and the pathogens they carry to pinpoint potential high risk areas for tick-borne disease transmission. In a joint Scandinavian study, we measured Ixodes ricinus instar abundance at 159 sites in southern Scandinavia in August-September, 2016, and collected 29,440 tick nymphs at 50 of these sites. We additionally measured abundance at 30 sites in August-September, 2017. We tested the 29,440 tick nymphs in pools of 10 in a Fluidigm real-time PCR chip to screen for 17 different tick-associated pathogens, 2 pathogen groups and 3 tick species. We present data on the geolocation, habitat type and instar abundance of the surveyed sites, as well as presence/absence of each pathogen in all analysed pools from the 50 collection sites and individual prevalence for each site. These data can be used alone or in combination with other data for predictive modelling and mapping of high-risk areas.
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Affiliation(s)
- Lene Jung Kjær
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.
| | - Kirstine Klitgaard
- Department for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | - Arnulf Soleng
- Department of Pest Control, Norwegian Institute of Public Health, Oslo, Norway
| | | | | | - Katrine M Paulsen
- Department of Virology, Norwegian Institute of Public Health, Oslo, Norway
- Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | | | - Lars Korslund
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Vivian Kjelland
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
- Sørlandet Hospital Health Enterprise, Research Unit, Kristiansand, Norway
| | - Audun Slettan
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Snorre Stuen
- Department of Production Animal Clinical Sciences, Section of Small Ruminant Research, Norwegian University of Life Sciences, Sandnes, Norway
| | - Petter Kjellander
- Department of Ecology, Grimsö Wildlife Research Station, Swedish University of Agricultural Sciences, Riddarhyttan, Sweden
| | - Madeleine Christensson
- Department of Ecology, Grimsö Wildlife Research Station, Swedish University of Agricultural Sciences, Riddarhyttan, Sweden
| | - Malin Teräväinen
- Department of Ecology, Grimsö Wildlife Research Station, Swedish University of Agricultural Sciences, Riddarhyttan, Sweden
| | - Andreas Baum
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Lyngby, Denmark
| | - Laura Mark Jensen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - René Bødker
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
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Kjær LJ, Soleng A, Edgar KS, Lindstedt HEH, Paulsen KM, Andreassen ÅK, Korslund L, Kjelland V, Slettan A, Stuen S, Kjellander P, Christensson M, Teräväinen M, Baum A, Klitgaard K, Bødker R. Predicting and mapping human risk of exposure to Ixodes ricinus nymphs using climatic and environmental data, Denmark, Norway and Sweden, 2016. ACTA ACUST UNITED AC 2020; 24. [PMID: 30862329 PMCID: PMC6402176 DOI: 10.2807/1560-7917.es.2019.24.9.1800101] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BackgroundTick-borne diseases have become increasingly common in recent decades and present a health problem in many parts of Europe. Control and prevention of these diseases require a better understanding of vector distribution.AimOur aim was to create a model able to predict the distribution of Ixodes ricinus nymphs in southern Scandinavia and to assess how this relates to risk of human exposure.MethodsWe measured the presence of I. ricinus tick nymphs at 159 stratified random lowland forest and meadow sites in Denmark, Norway and Sweden by dragging 400 m transects from August to September 2016, representing a total distance of 63.6 km. Using climate and remote sensing environmental data and boosted regression tree modelling, we predicted the overall spatial distribution of I. ricinus nymphs in Scandinavia. To assess the potential public health impact, we combined the predicted tick distribution with human density maps to determine the proportion of people at risk.ResultsOur model predicted the spatial distribution of I. ricinus nymphs with a sensitivity of 91% and a specificity of 60%. Temperature was one of the main drivers in the model followed by vegetation cover. Nymphs were restricted to only 17.5% of the modelled area but, respectively, 73.5%, 67.1% and 78.8% of the human populations lived within 5 km of these areas in Denmark, Norway and Sweden.ConclusionThe model suggests that increasing temperatures in the future may expand tick distribution geographically in northern Europe, but this may only affect a small additional proportion of the human population.
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Affiliation(s)
- Lene Jung Kjær
- Department for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | - Arnulf Soleng
- Department of Pest Control, Norwegian Institute of Public Health, Oslo, Norway
| | | | | | - Katrine Mørk Paulsen
- Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Oslo Norway.,Department of Virology, Norwegian Institute of Public Health, Oslo, Norway
| | | | - Lars Korslund
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Vivian Kjelland
- Sørlandet Hospital Health Enterprise, Research Unit, Kristiansand, Norway.,Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Audun Slettan
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Snorre Stuen
- Department of Production Animal Clinical Sciences, Section of Small Ruminant Research, Norwegian University of Life Sciences, Sandnes, Norway
| | - Petter Kjellander
- Department of Ecology, Wildlife Ecology Unit, Swedish University of Agricultural Sciences, Grimsö, Sweden
| | - Madeleine Christensson
- Department of Ecology, Wildlife Ecology Unit, Swedish University of Agricultural Sciences, Grimsö, Sweden
| | - Malin Teräväinen
- Department of Ecology, Wildlife Ecology Unit, Swedish University of Agricultural Sciences, Grimsö, Sweden
| | - Andreas Baum
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Lyngby, Denmark
| | - Kirstine Klitgaard
- Department for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | - René Bødker
- Department for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
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Jung Kjær L, Soleng A, Edgar KS, Lindstedt HEH, Paulsen KM, Andreassen ÅK, Korslund L, Kjelland V, Slettan A, Stuen S, Kjellander P, Christensson M, Teräväinen M, Baum A, Klitgaard K, Bødker R. Predicting the spatial abundance of Ixodes ricinus ticks in southern Scandinavia using environmental and climatic data. Sci Rep 2019; 9:18144. [PMID: 31792296 PMCID: PMC6889419 DOI: 10.1038/s41598-019-54496-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 11/15/2019] [Indexed: 01/24/2023] Open
Abstract
Recently, focus on tick-borne diseases has increased as ticks and their pathogens have become widespread and represent a health problem in Europe. Understanding the epidemiology of tick-borne infections requires the ability to predict and map tick abundance. We measured Ixodes ricinus abundance at 159 sites in southern Scandinavia from August-September, 2016. We used field data and environmental variables to develop predictive abundance models using machine learning algorithms, and also tested these models on 2017 data. Larva and nymph abundance models had relatively high predictive power (normalized RMSE from 0.65–0.69, R2 from 0.52–0.58) whereas adult tick models performed poorly (normalized RMSE from 0.94–0.96, R2 from 0.04–0.10). Testing the models on 2017 data produced good results with normalized RMSE values from 0.59–1.13 and R2 from 0.18–0.69. The resulting 2016 maps corresponded well with known tick abundance and distribution in Scandinavia. The models were highly influenced by temperature and vegetation, indicating that climate may be an important driver of I. ricinus distribution and abundance in Scandinavia. Despite varying results, the models predicted abundance in 2017 with high accuracy. The models are a first step towards environmentally driven tick abundance models that can assist in determining risk areas and interpreting human incidence data.
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Affiliation(s)
- Lene Jung Kjær
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark. .,Department for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark.
| | - Arnulf Soleng
- Department of Pest Control, Norwegian Institute of Public Health, Oslo, Norway
| | | | | | - Katrine Mørk Paulsen
- Department of Virology, Norwegian Institute of Public Health, Oslo, Norway.,Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | | | - Lars Korslund
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Vivian Kjelland
- Department of Natural Sciences, University of Agder, Kristiansand, Norway.,Sørlandet Hospital Health Enterprise, Research Unit, Kristiansand, Norway
| | - Audun Slettan
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Snorre Stuen
- Department of Production Animal Clinical Sciences, Section of Small Ruminant Research, Norwegian University of Life Sciences, Sandnes, Norway
| | - Petter Kjellander
- Department of Ecology, Wildlife Ecology Unit, Swedish University of Agricultural Sciences, Grimsö, Sweden
| | - Madeleine Christensson
- Department of Ecology, Wildlife Ecology Unit, Swedish University of Agricultural Sciences, Grimsö, Sweden
| | - Malin Teräväinen
- Department of Ecology, Wildlife Ecology Unit, Swedish University of Agricultural Sciences, Grimsö, Sweden
| | - Andreas Baum
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Lyngby, Denmark
| | - Kirstine Klitgaard
- Department for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | - René Bødker
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.,Department for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
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Kjær LJ, Soleng A, Edgar KS, Lindstedt HEH, Paulsen KM, Andreassen ÅK, Korslund L, Kjelland V, Slettan A, Stuen S, Kjellander P, Christensson M, Teräväinen M, Baum A, Isbrand A, Jensen LM, Klitgaard K, Bødker R. A large-scale screening for the taiga tick, Ixodes persulcatus, and the meadow tick, Dermacentor reticulatus, in southern Scandinavia, 2016. Parasit Vectors 2019; 12:338. [PMID: 31288866 PMCID: PMC6617640 DOI: 10.1186/s13071-019-3596-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/03/2019] [Indexed: 12/30/2022] Open
Abstract
The taiga tick, Ixodes persulcatus, has previously been limited to eastern Europe and northern Asia, but recently its range has expanded to Finland and northern Sweden. The species is of medical importance, as it, along with a string of other pathogens, may carry the Siberian and Far Eastern subtypes of tick-borne encephalitis virus. These subtypes appear to cause more severe disease, with higher fatality rates than the central European subtype. Until recently, the meadow tick, Dermacentor reticulatus, has been absent from Scandinavia, but has now been detected in Denmark, Norway and Sweden. Dermacentor reticulatus carries, along with other pathogens, Babesia canis and Rickettsia raoultii. Babesia canis causes severe and often fatal canine babesiosis, and R. raoultii may cause disease in humans. We collected 600 tick nymphs from each of 50 randomly selected sites in Denmark, southern Norway and south-eastern Sweden in August–September 2016. We tested pools of 10 nymphs in a Fluidigm real time PCR chip to screen for I. persulcatus and D. reticulatus, as well as tick-borne pathogens. Of all the 30,000 nymphs tested, none were I. persulcatus or D. reticulatus. Our results suggest that I. persulcatus is still limited to the northern parts of Sweden, and have not expanded into southern parts of Scandinavia. According to literature reports and supported by our screening results, D. reticulatus may yet only be an occasional guest in Scandinavia without established populations.
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Affiliation(s)
- Lene Jung Kjær
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark.
| | - Arnulf Soleng
- Department of Pest Control, Norwegian Institute of Public Health, Oslo, Norway
| | | | | | - Katrine Mørk Paulsen
- Department of Virology, Norwegian Institute of Public Health, Oslo, Norway.,Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, Oslo, Norway
| | | | - Lars Korslund
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Vivian Kjelland
- Department of Natural Sciences, University of Agder, Kristiansand, Norway.,Sørlandet Hospital Health Enterprise, Research Unit, Kristiansand, Norway
| | - Audun Slettan
- Department of Natural Sciences, University of Agder, Kristiansand, Norway
| | - Snorre Stuen
- Department of Production Animal Clinical Sciences, Section of Small Ruminant Research, Norwegian University of Life Sciences, Sandnes, Norway
| | - Petter Kjellander
- Wildlife Ecology Unit, Department of Ecology, Swedish University of Agricultural Sciences, Grimsö, Sweden
| | - Madeleine Christensson
- Wildlife Ecology Unit, Department of Ecology, Swedish University of Agricultural Sciences, Grimsö, Sweden
| | - Malin Teräväinen
- Wildlife Ecology Unit, Department of Ecology, Swedish University of Agricultural Sciences, Grimsö, Sweden
| | - Andreas Baum
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Lyngby, Denmark
| | - Anastasia Isbrand
- Department for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | - Laura Mark Jensen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Kirstine Klitgaard
- Department for Diagnostics and Scientific Advice, National Veterinary Institute, Technical University of Denmark, Lyngby, Denmark
| | - René Bødker
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
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7
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Klitgaard K, Højgaard J, Isbrand A, Madsen JJ, Thorup K, Bødker R. Screening for multiple tick-borne pathogens in Ixodes ricinus ticks from birds in Denmark during spring and autumn migration seasons. Ticks Tick Borne Dis 2019; 10:546-552. [DOI: 10.1016/j.ttbdis.2019.01.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 12/15/2022]
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8
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Kontturi M, Junni R, Simojoki H, Malinen E, Seuna E, Klitgaard K, Kujala-Wirth M, Soveri T, Pelkonen S. Bacterial species associated with interdigital phlegmon outbreaks in Finnish dairy herds. BMC Vet Res 2019; 15:44. [PMID: 30696445 PMCID: PMC6352363 DOI: 10.1186/s12917-019-1788-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 01/18/2019] [Indexed: 11/10/2022] Open
Abstract
Background Severe outbreaks of bovine interdigital phlegmon (IP) have occurred recently in several free stall dairy herds in Finland. We studied the aetiology of IP in such herds, and the association of bacterial species with the various stages of IP and herds of various morbidity of IP. Nineteen free stall dairy herds with IP outbreaks and three control herds were visited and bacteriological samples collected from cows suffering from IP (n = 106), other hoof diseases (n = 58), and control cows (n = 64). The herds were divided into high morbidity (morbidity ≥50%) and moderate morbidity groups (9–33%) based on morbidity during the first two months of the outbreak. Results F. necrophorum subspecies necrophorum was clearly associated with IP in general, and T. pyogenes was associated with the healing stage of IP. Six other major hoof pathogens were detected; Dichelobacter nodosus, Porphyromonas levii, Prevotella melaninogenica, Treponema spp. and Trueperella pyogenes. Most of the samples of acute IP (66.7%) harboured both F. necrophorum and D. nodosus. We found differences between moderate morbidity and high morbidity herds. D. nodosus was more common in IP lesion in high than in moderate morbidity herds. Conclusions Our result confirms that F. necrophorum subspecies necrophorum is the main pathogen in IP, but also T. pyogenes is associated with the healing stage of IP. Our results suggest that D. nodosus may play a role in the severity of the outbreak of IP, but further research is needed to establish other bacteriological factors behind these severe outbreaks.
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Affiliation(s)
- Miia Kontturi
- Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Paroninkuja 20, 04920, Saarentaus, Finland.
| | - Reijo Junni
- Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Paroninkuja 20, 04920, Saarentaus, Finland
| | - Heli Simojoki
- Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Paroninkuja 20, 04920, Saarentaus, Finland
| | - Erja Malinen
- Veterinary Bacteriology and Pathology unit, Finnish Food Authority, Mustialankatu 3, 00790, Helsinki, Finland
| | - Eija Seuna
- Veterinary Bacteriology and Pathology unit, Finnish Food Authority, Mustialankatu 3, 00790, Helsinki, Finland
| | - Kirstine Klitgaard
- National Veterinary Institute, Technical University of Denmark, Kemitorvet, Building 202, 2800, Kgs. Lyngby, Denmark
| | - Minna Kujala-Wirth
- Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Paroninkuja 20, 04920, Saarentaus, Finland
| | - Timo Soveri
- Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Paroninkuja 20, 04920, Saarentaus, Finland
| | - Sinikka Pelkonen
- Veterinary Bacteriology and Pathology unit, Finnish Food Authority, Mustialankatu 3, 00790, Helsinki, Finland
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Gondard M, Michelet L, Nisavanh A, Devillers E, Delannoy S, Fach P, Aspan A, Ullman K, Chirico J, Hoffmann B, van der Wal FJ, de Koeijer A, van Solt-Smits C, Jahfari S, Sprong H, Mansfield KL, Fooks AR, Klitgaard K, Bødker R, Moutailler S. Prevalence of tick-borne viruses in Ixodes ricinus assessed by high-throughput real-time PCR. Pathog Dis 2018; 76:5181333. [PMID: 30423120 DOI: 10.1093/femspd/fty083] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 11/12/2018] [Indexed: 12/18/2022] Open
Abstract
Ticks are one of the principal arthropod vectors of human and animal infectious diseases. Whereas the prevalence of tick-borne encephalitis virus in ticks in Europe is well studied, there is less information available on the prevalence of the other tick-borne viruses (TBVs) existing worldwide. The aim of this study was to improve the epidemiological survey tools of TBVs by the development of an efficient high-throughput test to screen a wide range of viruses in ticks.In this study, we developed a new high-throughput virus-detection assay based on parallel real-time PCRs on a microfluidic system, and used it to perform a large scale epidemiological survey screening for the presence of 21 TBVs in 18 135 nymphs of Ixodes ricinus collected from five European countries. This extensive investigation has (i) evaluated the prevalence of four viruses present in the collected ticks, (ii) allowed the identification of viruses in regions where they were previously undetected.In conclusion, we have demonstrated the capabilities of this new screening method that allows the detection of numerous TBVs in a large number of ticks. This tool represents a powerful and rapid system for TBVs surveillance in Europe and could be easily customized to assess viral emergence.
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Affiliation(s)
- Mathilde Gondard
- UMR BIPAR, Animal Health Laboratory, ANSES, INRA, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est, 14 Rue P. et M. Curie, 94700 Maisons-Alfort, France
| | - Lorraine Michelet
- UMR BIPAR, Animal Health Laboratory, ANSES, INRA, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est, 14 Rue P. et M. Curie, 94700 Maisons-Alfort, France
| | - Athinna Nisavanh
- UMR BIPAR, Animal Health Laboratory, ANSES, INRA, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est, 14 Rue P. et M. Curie, 94700 Maisons-Alfort, France
| | - Elodie Devillers
- UMR BIPAR, Animal Health Laboratory, ANSES, INRA, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est, 14 Rue P. et M. Curie, 94700 Maisons-Alfort, France
| | - Sabine Delannoy
- IdentyPath Platform, Food Safety Laboratory, ANSES, 14 Rue P. et M. Curie, 94700 Maisons-Alfort, France
| | - Patrick Fach
- IdentyPath Platform, Food Safety Laboratory, ANSES, 14 Rue P. et M. Curie, 94700 Maisons-Alfort, France
| | - Anna Aspan
- Department of Microbiology, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden
| | - Karin Ullman
- Department of Microbiology, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden
| | - Jan Chirico
- Department of Microbiology, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden
| | - Bernd Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Sü dufer 10, 17493 Greifswald - Insel Riems, Germany
| | - Fimme Jan van der Wal
- Wageningen Bioveterinary Research (WBVR), Wageningen UR, Houtribweg 39, 8221 RA Lelystad, The Netherlands
| | - Aline de Koeijer
- Wageningen Bioveterinary Research (WBVR), Wageningen UR, Houtribweg 39, 8221 RA Lelystad, The Netherlands
| | - Conny van Solt-Smits
- Wageningen Bioveterinary Research (WBVR), Wageningen UR, Houtribweg 39, 8221 RA Lelystad, The Netherlands
| | - Seta Jahfari
- Laboratory for Zoonoses and Environmental Microbiology, National Institute for Public Health and Environment (RIVM), Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands
| | - Hein Sprong
- Laboratory for Zoonoses and Environmental Microbiology, National Institute for Public Health and Environment (RIVM), Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands
| | - Karen L Mansfield
- Animal and Plant Health Agency (APHA), Woodham Lane, New Haw, Addlestone, Surrey, KT15 3NB, United Kingdom
| | - Anthony R Fooks
- Animal and Plant Health Agency (APHA), Woodham Lane, New Haw, Addlestone, Surrey, KT15 3NB, United Kingdom
| | - Kirstine Klitgaard
- National Veterinary Institute, DTU, Henrik Dams Allé, Building 205B, 2800 Kgs. Lyngby, Denmark
| | - Rene Bødker
- National Veterinary Institute, DTU, Henrik Dams Allé, Building 205B, 2800 Kgs. Lyngby, Denmark
| | - Sara Moutailler
- UMR BIPAR, Animal Health Laboratory, ANSES, INRA, Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est, 14 Rue P. et M. Curie, 94700 Maisons-Alfort, France
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10
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Klitgaard K, Chriél M, Isbrand A, Jensen TK, Bødker R. Identification of Dermacentor reticulatus Ticks Carrying Rickettsia raoultii on Migrating Jackal, Denmark. Emerg Infect Dis 2018; 23:2072-2074. [PMID: 29148376 PMCID: PMC5708226 DOI: 10.3201/eid2312.170919] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
From a migrating golden jackal (Canis aureus), we retrieved 21 live male Dermacentor reticulatus ticks, a species not previously reported from wildlife in Denmark. We identified Rickettsia raoultii from 18 (86%) of the ticks. This bacterium is associated with scalp eschar and neck lymphadenopathy after tick bite syndrome among humans.
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11
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Karstrup CC, Aalbæk B, Klitgaard K, Jensen TK, Pedersen HG, Agerholm JS. Colonization of the bovine uterus by Candida kefyr. Acta Vet Scand 2017; 59:61. [PMID: 28915910 PMCID: PMC5603010 DOI: 10.1186/s13028-017-0329-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/09/2017] [Indexed: 11/23/2022] Open
Abstract
Background While fungal infections of the bovine uterus are well-known diseases in pregnant cattle, very limited knowledge exists on the presence and significance of fungi in the uterus of non-pregnant cows. Presence of fungi in the uterine lumen of postpartum (pp) cows has been reported, but little attention has been paid to this as most studies of the bovine pp uterus have focused on bacteria. Case presentation Microscopy of uterine lavage cytology slides of three cows from one herd revealed the presence of numerous yeast-like organisms, which were located either free in the fluid or within macrophages. Two of the cows were around 30 days pp, while the third was 7 months pp. None of the cows had been treated with antibiotics. Culturing of the flush samples was unsuccessful, but Sanger sequencing of DNA extracted from an endometrial biopsy of one of the cows revealed the presence of Candida kefyr (Kluyveromyces marxianus). Fluorescence in situ hybridization examination of endometrial tissue sections of two cows using probes targeting 18S rRNA of the K. marxianus group was performed and revealed the presence of yeast cells on the endometrium. Histology was performed and demonstrated hyphal and non-hyphal yeast-like organisms on the surface of endometrium and in the crypts. Tissue invasion was restricted to the superficial part of the epithelium and although endometrial inflammation was present, this was mild and considered as not being caused by the fungi. One of the cows became pregnant and delivered a normal calf at term, while the two others were not bred. Conclusions Candida kefyr is commonly isolated from milk of cows with mastitis, but has not been reported in association with other diseases of cattle. The infection was present as a monoculture in all three cows, but the fungi had only colonized the uterine lumen and the endometrial surface. Only a mild non-suppurative endometrial inflammation was present, but within the uterine luminal content, many macrophages having phagocytized yeast cells were present. Re-examination of the cows did not reveal a persistent infection, so the infection probably resolved spontaneously. Electronic supplementary material The online version of this article (doi:10.1186/s13028-017-0329-5) contains supplementary material, which is available to authorized users.
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Karstrup CC, Klitgaard K, Jensen TK, Agerholm JS, Pedersen HG. Presence of bacteria in the endometrium and placentomes of pregnant cows. Theriogenology 2017; 99:41-47. [DOI: 10.1016/j.theriogenology.2017.05.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/17/2017] [Accepted: 05/17/2017] [Indexed: 01/13/2023]
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13
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Jensen PM, Christoffersen CS, Moutailler S, Michelet L, Klitgaard K, Bødker R. Transmission differentials for multiple pathogens as inferred from their prevalence in larva, nymph and adult of Ixodes ricinus (Acari: Ixodidae). Exp Appl Acarol 2017; 71:171-182. [PMID: 28255923 DOI: 10.1007/s10493-017-0110-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 02/04/2017] [Indexed: 06/06/2023]
Abstract
Ixodes ricinus serves as vector for a range of microorganisms capable of causing clinical illness in humans. The microorganisms occur in the same vector populations and are generally affected by the same tick-host interactions. Still, the instars have different host preferences which should manifest in different transmission patterns for various microorganisms in the tick populations, i.e., most microorganisms increase in prevalence rate from larvae to nymphs because their reservoirs are among small mammals and birds that serve as blood hosts for larvae. Other microorganisms, like Anaplasma phagocytophilum, mainly increase in prevalence rates from nymphs to adults, because their reservoirs are larger ungulates that serve as primary blood hosts for nymphs and adults. We sampled a representative sample of ticks from 12 locations on Zealand and Funen, Denmark, and investigated the differences in prevalence rate of infection in larvae, nymphs and adults for multiple pathogens. Prevalence of infection for larvae, nymphs and adults, respectively, was: 0, 1.5 and 4.5% for Borrelia burgdorferi; 0, 4.2 and 3.9% for Borrelia garinii; 0, 6.6 and 6.1% for Borrelia afzelii; 0, 0 and 0.6% for Borrelia valaisiana; 0, 3.7 and 0.6% for Borrelia spielmanii; 0, 0.7 and 1.2% for Babesia divergens; 0, 0, 0.6% for Babesia venatorum; 0, 1.5 and 6.1% for A. phagocytophilum. The results were in general compatible with the hypothesis i.e., that differences in blood host for larvae and nymphs define differences in transmission of infectious agents, but other factors than differences in blood hosts between larvae and nymphs may also be important to consider.
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Affiliation(s)
- Per M Jensen
- Department for Plant and Environment, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark.
| | - Christian S Christoffersen
- Department for Plant and Environment, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark
| | - Sara Moutailler
- UMR BIPAR, ANSES, INRA, ENVA, 14 Rue Pierre et Marie Curie, 94706, Maisons-Alfort Cedex, Paris, France
| | - Lorraine Michelet
- UMR BIPAR, ANSES, INRA, ENVA, 14 Rue Pierre et Marie Curie, 94706, Maisons-Alfort Cedex, Paris, France
| | - Kirstine Klitgaard
- National Veterinary Institute, Danish Technical University, Bülowsvej 27, 1871, Frederiksberg, Denmark
| | - Rene Bødker
- National Veterinary Institute, Danish Technical University, Bülowsvej 27, 1871, Frederiksberg, Denmark
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14
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Karstrup CC, Agerholm JS, Jensen TK, Swaro LRV, Klitgaard K, Rasmussen EL, Krogh KM, Pedersen HG. Presence and localization of bacteria in the bovine endometrium postpartum using fluorescence in situ hybridization. Theriogenology 2017; 92:167-175. [PMID: 28237333 DOI: 10.1016/j.theriogenology.2017.01.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 01/13/2017] [Accepted: 01/15/2017] [Indexed: 12/26/2022]
Abstract
The aim of this study was to investigate bacterial invasiveness of the bovine endometrium during the postpartum period. Fluorescence in situ hybridization was applied to endometrial biopsies using probes for Fusobacterium necrophorum, Porphyromonas levii, Trueperella pyogenes, Escherichia coli and a probe for bacteria in general (the overall domain Bacteria) to determine their tissue localization. Holstein cows were sampled at three time points postpartum (T1: 4-12 days postpartum, T2: 24-32 days postpartum and T3: 46-54 days postpartum). At T1, cows were clinically scored as having a uterine infection based on presence of a brownish, fetid vaginal discharge or as normal if having normal lochia. An endometrial biopsy was taken from all cows at T1 (n = 57). Endometrial biopsies were taken from the same cows at T2 and T3 if allowed by the size of the cervical canal and if the cow had not been inseminated. Fifty and 39 biopsies were obtained at T2 and T3, respectively. The biopsies were evaluated for inflammation and for presence and localization of bacteria. When analyzed by the probe for the entire domain Bacteria, bacteria were found in most biopsies irrespectively of time (T1: 79.0%, T2: 82.0%, T3: 89.7%). Fusobacterium necrophorum and Porphyromonas levii were often present in the endometrium at T1 (61.1% and 47.8%, respectively), but the prevalence decreased significantly over time. Trueperella pyogenes and Escherichia coli were less prevalent at T1 (8.8% and 10.5%, respectively) and their prevalence also decreased significantly over time. Fusobacterium necrophorum and Porphyromonas levii were often co-localized intraepithelially or in the lamina propria. Trueperella pyogenes and Escherichia coli were located only on the endometrial surface. Due to the high prevalence of tissue invasiveness, these findings emphasize the importance of Fusobacterium necrophorum and Porphyromonas levii in postpartum uterine disease of cattle and indicate that tissue invasiveness is an important aspect of the pathogenesis.
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Affiliation(s)
- C C Karstrup
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlægevej 68, DK-1870, Frederiksberg, Denmark
| | - J S Agerholm
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlægevej 68, DK-1870, Frederiksberg, Denmark
| | - T K Jensen
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, DK-1870, Frederiksberg, Denmark
| | - L R V Swaro
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, DK-1870, Frederiksberg, Denmark
| | - K Klitgaard
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, DK-1870, Frederiksberg, Denmark
| | - E L Rasmussen
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlægevej 68, DK-1870, Frederiksberg, Denmark
| | - K M Krogh
- Landbrugets Veterinære Konsulenttjeneste, Fynsvej 8, DK-9500, Hobro, Denmark
| | - H G Pedersen
- Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlægevej 68, DK-1870, Frederiksberg, Denmark.
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15
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Marcatili P, Nielsen MW, Sicheritz-Pontén T, Jensen TK, Schafer-Nielsen C, Boye M, Nielsen M, Klitgaard K. A novel approach to probe host-pathogen interactions of bovine digital dermatitis, a model of a complex polymicrobial infection. BMC Genomics 2016; 17:987. [PMID: 27908274 PMCID: PMC5142292 DOI: 10.1186/s12864-016-3341-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 11/24/2016] [Indexed: 11/17/2022] Open
Abstract
Background Polymicrobial infections represent a great challenge for the clarification of disease etiology and the development of comprehensive diagnostic or therapeutic tools, particularly for fastidious and difficult-to-cultivate bacteria. Using bovine digital dermatitis (DD) as a disease model, we introduce a novel strategy to study the pathogenesis of complex infections. Results The strategy combines meta-transcriptomics with high-density peptide-microarray technology to screen for in vivo-expressed microbial genes and the host antibody response at the site of infection. Bacterial expression patterns supported the assumption that treponemes were the major DD pathogens but also indicated the active involvement of other phyla (primarily Bacteroidetes). Bacterial genes involved in chemotaxis, flagellar synthesis and protection against oxidative and acidic stress were among the major factors defining the disease. Conclusions The extraordinary diversity observed in bacterial expression, antigens and host antibody responses between individual cows pointed toward microbial variability as a hallmark of DD. Persistence of infection and DD reinfection in the same individual is common; thus, high microbial diversity may undermine the host’s capacity to mount an efficient immune response and maintain immunological memory towards DD. The common antigenic markers identified here using a high-density peptide microarray address this issue and may be useful for future preventive measures against DD. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3341-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Paolo Marcatili
- Center for Biological Sequence analysis, Technical University of Denmark, Kemitorvet, 2800 Kgs., Lyngby, Denmark.
| | - Martin W Nielsen
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870, Frederiksberg C, Denmark
| | - Thomas Sicheritz-Pontén
- Center for Biological Sequence analysis, Technical University of Denmark, Kemitorvet, 2800 Kgs., Lyngby, Denmark
| | - Tim K Jensen
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870, Frederiksberg C, Denmark
| | | | - Mette Boye
- Molecular Diagnostic and Clinical Research Unit, Hospital of Southern Jutland, 6400, Sønderborg, Denmark
| | - Morten Nielsen
- Center for Biological Sequence analysis, Technical University of Denmark, Kemitorvet, 2800 Kgs., Lyngby, Denmark.,Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, Buenos Aires, Argentina
| | - Kirstine Klitgaard
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870, Frederiksberg C, Denmark
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16
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Nielsen MW, Strube ML, Isbrand A, Al-Medrasi WDHM, Boye M, Jensen TK, Klitgaard K. Potential bacterial core species associated with digital dermatitis in cattle herds identified by molecular profiling of interdigital skin samples. Vet Microbiol 2016; 186:139-49. [PMID: 27016768 DOI: 10.1016/j.vetmic.2016.03.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/02/2016] [Accepted: 03/04/2016] [Indexed: 11/28/2022]
Abstract
Although treponemes are consistently identified in tissue from bovine digital dermatitis (DD) lesions, the definitive etiology of this debilitating polymicrobial disease is still unresolved. To study the microbiomes of 27 DD-infected and 10 healthy interdigital skin samples, we used a combination of different molecular methods. Deep sequencing of the 16S rRNA gene variable regions V1-V2 showed that Treponema, Mycoplasma, Fusobacterium and Porphyromonas were the genera best differentiating the DD samples from the controls. Additional deep sequencing analysis of the most abundant genus, Treponema, targeting another variable region of the 16S rRNA gene, V3-V4, identified 15 different phylotypes, among which Treponema phagedenis-like and Treponema refringens-like species were the most abundant. Although the presence of Treponema spp., Fusobacterium necrophorum and Porphyromonas levii was confirmed by fluorescence in situ hybridization (FISH), the results for Mycoplasma spp. were inconclusive. Extensive treponemal epidermal infiltration, constituting more than 90% of the total bacterial population, was observed in 24 of the 27 DD samples. F. necrophorum and P. levii were superficially located in the epidermal lesions and were present in only a subset of samples. RT-qPCR analysis showed that treponemes were also actively expressing a panel of virulence factors at the site of infection. Our results further support the hypothesis that species belonging to the genus Treponema are major pathogens of DD and also provide sufficient clues to motivate additional research into the role of M. fermentans, F. necrophorum and P. levii in the etiology of DD.
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Affiliation(s)
- Martin W Nielsen
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870 Frederiksberg C, Denmark
| | - Mikael L Strube
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870 Frederiksberg C, Denmark
| | - Anastasia Isbrand
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870 Frederiksberg C, Denmark
| | - Worood D H M Al-Medrasi
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870 Frederiksberg C, Denmark
| | - Mette Boye
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870 Frederiksberg C, Denmark
| | - Tim K Jensen
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870 Frederiksberg C, Denmark
| | - Kirstine Klitgaard
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870 Frederiksberg C, Denmark.
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17
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Knudsen LRV, Karstrup CC, Pedersen HG, Angen Ø, Agerholm JS, Rasmussen EL, Jensen TK, Klitgaard K. An investigation of the microbiota in uterine flush samples and endometrial biopsies from dairy cows during the first 7 weeks postpartum. Theriogenology 2016; 86:642-50. [PMID: 27039075 DOI: 10.1016/j.theriogenology.2016.02.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 02/12/2016] [Accepted: 02/19/2016] [Indexed: 12/31/2022]
Abstract
Metritis and endometritis commonly occur in dairy cows after calving. Although numerous studies have been performed to identify the causative pathogens, a complete overview has not been done. Metagenomic studies have analyzed the bacterial populations of uterine flush samples from postpartum (pp) dairy cows, but the microbiota in the uterine luminal fluid may differ from the microbiota of the endometrium itself, and important putative pathogens may have been overlooked. In the present study, we compared the microbiota of the uterine lumen and the endometrium of healthy, metritic, and endometritic cows. Samples were collected from 68 Holstein dairy cows at 1, 4, and 7 weeks pp, and the data were analyzed by deep sequencing of the V1 and V2 hypervariable regions of the 16S ribosomal RNA gene. The results showed that Porphyromonadaceae, Fusobacteriaceae, Leptotrichiaceae, and Mycoplasmataceae may be associated with uterine disease. The microbiota of the uterine flush samples and the endometrial biopsies were correlated, but the microbiota of the biopsies was more diverse. Fusobacteriaceae and Leptotrichiaceae were not observed in the biopsies at week 7, whereas they accounted for 20% and 13%, respectively, of the bacterial populations in the flush samples. The Mycoplasmataceae family was observed in much higher quantity in the flush samples than in the biopsies of the endometritis groups at weeks 4 and 7. Our findings support the observations of previous metagenomic studies and illustrate the importance of including endometrial biopsies to obtain more detailed knowledge of the pp uterine microbiota.
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Affiliation(s)
- Lif Rødtness Vesterby Knudsen
- Section for Bacteriology and Pathology, National Veterinary Institute, Technical University of Denmark, 1870 Frederiksberg C, Denmark
| | - Cecilia Christensen Karstrup
- Section for Veterinary Reproduction and Obstetrics, Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Hanne Gervi Pedersen
- Section for Veterinary Reproduction and Obstetrics, Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Øystein Angen
- Section for Bacteriology and Pathology, National Veterinary Institute, Technical University of Denmark, 1870 Frederiksberg C, Denmark
| | - Jørgen Steen Agerholm
- Section for Veterinary Reproduction and Obstetrics, Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Eva Láadal Rasmussen
- Section for Veterinary Reproduction and Obstetrics, Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
| | - Tim Kåre Jensen
- Section for Bacteriology and Pathology, National Veterinary Institute, Technical University of Denmark, 1870 Frederiksberg C, Denmark
| | - Kirstine Klitgaard
- Section for Bacteriology and Pathology, National Veterinary Institute, Technical University of Denmark, 1870 Frederiksberg C, Denmark.
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Brogaard L, Klitgaard K, Heegaard PMH, Hansen MS, Jensen TK, Skovgaard K. Concurrent host-pathogen gene expression in the lungs of pigs challenged with Actinobacillus pleuropneumoniae. BMC Genomics 2015; 16:417. [PMID: 26018580 PMCID: PMC4446954 DOI: 10.1186/s12864-015-1557-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 04/20/2015] [Indexed: 12/22/2022] Open
Abstract
Background Actinobacillus pleuropneumoniae causes pleuropneumonia in pigs, a disease which is associated with high morbidity and mortality, as well as impaired animal welfare. To obtain in-depth understanding of this infection, the interplay between virulence factors of the pathogen and defense mechanisms of the porcine host needs to be elucidated. However, research has traditionally focused on either bacteriology or immunology; an unbiased picture of the transcriptional responses can be obtained by investigating both organisms in the same biological sample. Results Host and pathogen responses in pigs experimentally infected with A. pleuropneumoniae were analyzed by high-throughput RT-qPCR. This approach allowed concurrent analysis of selected genes encoding proteins known or hypothesized to be important in the acute phase of this infection. The expression of 17 bacterial and 31 porcine genes was quantified in lung samples obtained within the first 48 hours of infection. This provided novel insight into the early time course of bacterial genes involved in synthesis of pathogen-associated molecular patterns (lipopolysaccharide, peptidoglycan, lipoprotein) and genes involved in pattern recognition (TLR4, CD14, MD2, LBP, MYD88) in response to A. pleuropneumoniae. Significant up-regulation of proinflammatory cytokines such as IL1B, IL6, and IL8 was observed, correlating with protein levels, infection status and histopathological findings. Host genes encoding proteins involved in iron metabolism, as well as bacterial genes encoding exotoxins, proteins involved in adhesion, and iron acquisition were found to be differentially expressed according to disease progression. By applying laser capture microdissection, porcine expression of selected genes could be confirmed in the immediate surroundings of the invading pathogen. Conclusions Microbial pathogenesis is the product of interactions between host and pathogen. Our results demonstrate the applicability of high-throughput RT-qPCR for the elucidation of dual-organism gene expression analysis during infection. We showed differential expression of 12 bacterial and 24 porcine genes during infection and significant correlation of porcine and bacterial gene expression. This is the first study investigating the concurrent transcriptional response of both bacteria and host at the site of infection during porcine respiratory infection. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1557-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Louise Brogaard
- Innate Immunology Group, Section of Immunology and Vaccinology, National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870, Frederiksberg C, Denmark.
| | - Kirstine Klitgaard
- Section of Bacteriology, Pathology and Parasitology, National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870, Frederiksberg C, Denmark.
| | - Peter M H Heegaard
- Innate Immunology Group, Section of Immunology and Vaccinology, National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870, Frederiksberg C, Denmark.
| | - Mette Sif Hansen
- Section of Bacteriology, Pathology and Parasitology, National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870, Frederiksberg C, Denmark.
| | - Tim Kåre Jensen
- Section of Bacteriology, Pathology and Parasitology, National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870, Frederiksberg C, Denmark.
| | - Kerstin Skovgaard
- Innate Immunology Group, Section of Immunology and Vaccinology, National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870, Frederiksberg C, Denmark.
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Jensen T, Strijkstra G, Gruys E, Baumgärtner W, Klitgaard K, Boye M. Detection of polytreponemal infection in three cases of porcine ulcerative stomatitis by fluorescence in-situ hybridization. J Comp Pathol 2015. [DOI: 10.1016/j.jcpa.2014.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Michelet L, Delannoy S, Devillers E, Umhang G, Aspan A, Juremalm M, Chirico J, van der Wal FJ, Sprong H, Boye Pihl TP, Klitgaard K, Bødker R, Fach P, Moutailler S. High-throughput screening of tick-borne pathogens in Europe. Front Cell Infect Microbiol 2014; 4:103. [PMID: 25120960 PMCID: PMC4114295 DOI: 10.3389/fcimb.2014.00103] [Citation(s) in RCA: 173] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 07/10/2014] [Indexed: 12/02/2022] Open
Abstract
Due to increased travel, climatic, and environmental changes, the incidence of tick-borne disease in both humans and animals is increasing throughout Europe. Therefore, extended surveillance tools are desirable. To accurately screen tick-borne pathogens (TBPs), a large scale epidemiological study was conducted on 7050 Ixodes ricinus nymphs collected from France, Denmark, and the Netherlands using a powerful new high-throughput approach. This advanced methodology permitted the simultaneous detection of 25 bacterial, and 12 parasitic species (including; Borrelia, Anaplasma, Ehrlichia, Rickettsia, Bartonella, Candidatus Neoehrlichia, Coxiella, Francisella, Babesia, and Theileria genus) across 94 samples. We successfully determined the prevalence of expected (Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Rickettsia helvetica, Candidatus Neoehrlichia mikurensis, Babesia divergens, Babesia venatorum), unexpected (Borrelia miyamotoi), and rare (Bartonella henselae) pathogens in the three European countries. Moreover we detected Borrelia spielmanii, Borrelia miyamotoi, Babesia divergens, and Babesia venatorum for the first time in Danish ticks. This surveillance method represents a major improvement in epidemiological studies, able to facilitate comprehensive testing of TBPs, and which can also be customized to monitor emerging diseases.
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Affiliation(s)
| | - Sabine Delannoy
- IdentyPath Platform, Food Safety Laboratory, ANSES Maisons-Alfort, France
| | - Elodie Devillers
- UMR BIPAR, Animal Health Laboratory, ANSES Maisons-Alfort, France
| | - Gérald Umhang
- Nancy Laboratory for Rabies and Wildlife, Wildlife EcoEPIdemiology and Surveillance Unit, ANSES Malzéville, France
| | - Anna Aspan
- Department of Bacteriology, National Veterinary Institute (SVA) Uppsala, Sweden
| | - Mikael Juremalm
- Department of Virology, Immunobiology and Parasitology, National Veterinary Institute (SVA) Uppsala, Sweden
| | - Jan Chirico
- Department of Virology, Immunobiology and Parasitology, National Veterinary Institute (SVA) Uppsala, Sweden
| | - Fimme J van der Wal
- Department of Infection Biology, Central Veterinary Institute, Wageningen UR Lelystad, Netherlands
| | - Hein Sprong
- Laboratory for Zoonoses and Environmental Microbiology, National Institute for Public Health and Environment (RIVM) Bilthoven, Netherlands
| | | | | | - Rene Bødker
- National Veterinary Institute, DTU Copenhagen, Denmark
| | - Patrick Fach
- IdentyPath Platform, Food Safety Laboratory, ANSES Maisons-Alfort, France
| | - Sara Moutailler
- UMR BIPAR, Animal Health Laboratory, ANSES Maisons-Alfort, France
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Michelet L, Delannoy S, Devillers E, Umhang G, Aspan A, Juremalm M, Chirico J, Van der Wal FJ, Sprong H, Boye Pihl TP, Klitgaard K, Bødker R, Fach P, Moutailler S. Multiple detection of pathogens in ticks: development of a high throughput real time PCR chip used as a new epidemiologic investigative tool. Parasit Vectors 2014. [PMCID: PMC4092299 DOI: 10.1186/1756-3305-7-s1-o12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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22
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Karlsson F, Klitgaard K, Jensen TK. Identification of Treponema pedis as the predominant Treponema species in porcine skin ulcers by fluorescence in situ hybridization and high-throughput sequencing. Vet Microbiol 2014; 171:122-31. [PMID: 24725449 DOI: 10.1016/j.vetmic.2014.03.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 03/07/2014] [Accepted: 03/12/2014] [Indexed: 11/20/2022]
Abstract
Skin lesions often seen in pig production are of great animal welfare concern. To study the potential role of Treponema bacteria in porcine skin ulcers, we investigated the presence and distribution of these organisms in decubital shoulder ulcers (n=51) and ear necroses (n=54) by fluorescence in situ hybridization (FISH) and high-throughput sequencing. In addition, two cases of facial ulcers and five cases of other skin ulcers were included in the study. Samples from all 112 skin lesions and intact skin from pigs without skin ulcers (n=14) were screened by FISH. Three different oligonucleotide probes targeting 16S rRNA were used, specific for domain bacterium, Treponema spp. and species T. pedis. Screening showed that two cases each of facial and other ulcers, 35 (69%) of shoulder ulcers and 32 (59%) of ear necroses were positive for Treponema spp. T. pedis was the unequivocally, predominant species typically constituting more than 90% of the treponemes in a lesion, assessed visually by microscopy. Altogether, T. pedis was demonstrated in 69 of the 71 Treponema spp. positive lesions. We conclude that Treponema spp. are frequently present and abundant in various skin ulcers of pigs. The results from this study point toward an important role of T. pedis as a secondary bacterial infection in porcine skin ulcers, especially in severe and chronic lesions.
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Affiliation(s)
- Frida Karlsson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, SE-75007 Uppsala, Sweden.
| | - Kirstine Klitgaard
- National Veterinary Institute, Technical University of Denmark, 1870 Frederiksberg, Denmark
| | - Tim Kåre Jensen
- National Veterinary Institute, Technical University of Denmark, 1870 Frederiksberg, Denmark
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Knappe-Poindecker M, Gilhuus M, Jensen TK, Klitgaard K, Larssen RB, Fjeldaas T. Interdigital dermatitis, heel horn erosion, and digital dermatitis in 14 Norwegian dairy herds. J Dairy Sci 2013; 96:7617-29. [PMID: 24140335 DOI: 10.3168/jds.2013-6717] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 08/28/2013] [Indexed: 11/19/2022]
Abstract
The aim of this study was to assess infectious foot diseases, including identification and characterization of Dichelobacter nodosus and Treponema spp., in herds having problems with interdigital dermatitis (ID) and heel horn erosion (E) and in control herds expected to have few problems. We also wanted to compare diseased and healthy cows in all herds. The study included 14 dairy herds with a total of 633 cows. Eight herds had a history of ID and E, and 6 were control herds. All cows were scored for lameness, and infectious foot diseases on the hind feet were recorded after trimming. Swabs and biopsies were taken from the skin of 10 cows in each herd for bacterial analyses. In total, samples were taken from 34 cows with ID, 11 with E, 40 with both ID and E, and 8 with digital dermatitis (DD), and from 47 cows with healthy feet. Swabs were analyzed for identification and characterization of D. nodosus by PCR, culture, virulence testing, and serotyping. Biopsies were analyzed by fluorescent in situ hybridization regarding histopathology, identification, and characterization of Treponema spp., and identification of D. nodosus. Interdigital dermatitis was the most frequent foot disease, with a prevalence of 50.4% in problem herds compared with 26.8% in control herds. Heel horn erosion was recorded in 34.8% of the cows in problem herds compared with 22.1% in control herds. Dichelobacter nodosus was detected in 97.1% of the cows with ID, in 36.4% with E, in all cows with both ID and E, in all cows with DD, and in 66.0% of cows with healthy feet. All serogroups of D. nodosus except F and M were detected, and all isolates were defined as benign by the gelatin gel test. Treponema spp. were detected in 50.0% of the cows with ID, in 9.1% with E, in 67.5% with ID and E, in all cows with DD, and in 6.4% of those with healthy feet. In total, 6 previously described phylotypes (PT) of Treponema were detected: PT1, PT3, PT6, PT13, and PT15 in cows with ID, PT1 in a cow with E, and PT1, PT2, PT3, PT6, and PT13 in cows with both ID and E. One new phylotype (PT19) was identified. The epidermal damage score was higher but the difference in inflammatory response of the dermis was minor in cows with ID versus those with healthy feet. Fisher's exact test revealed an association between ID and D. nodosus, and between ID and Treponema spp. Logistic regression revealed an association between both ID and E and dirty claws (odds ratios=1.9 and 2.0, respectively). Our study indicates that D. nodosus, Treponema spp., and hygiene are involved in the pathogenesis of ID.
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Affiliation(s)
- M Knappe-Poindecker
- Department of Production Animal Clinical Sciences, Norwegian School of Veterinary Science, PO Box 8146, 0033 Oslo, Norway.
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Rasmussen M, Capion N, Klitgaard K, Rogdo T, Fjeldaas T, Boye M, Jensen TK. Bovine digital dermatitis: possible pathogenic consortium consisting of Dichelobacter nodosus and multiple Treponema species. Vet Microbiol 2012; 160:151-61. [PMID: 22698300 DOI: 10.1016/j.vetmic.2012.05.018] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 05/10/2012] [Accepted: 05/14/2012] [Indexed: 11/17/2022]
Abstract
Bovine digital dermatitis (DD) is a multifactorial disease involving at least one or more treponemal species. Virulent phylotypes of Treponema and other infectious agents contributing to disease etiology still remain to be identified. This study addressed these questions by analyzing the prevalence and distribution of seventeen phylotypes of Treponema in DD lesions by fluorescent in situ hybridization (FISH) applying species/phylotype-specific oligonucleotide probes. In situ hybridization for Dichelobacter nodosus, the cause of ovine footrot, was additionally performed. We sampled 90 biopsies of DD lesions originating from one Norwegian and six Danish dairy herds, and 24 tissue samples of healthy skin. All lesions revealed intermingled infections with multiple Treponema phylotypes (mean>7). In six herds, the mean number of phylotypes identified varied between 12 and 15. D. nodosus was present in forty-nine (51%) of the lesions and in three of the apparently healthy skin samples. Two "healthy" samples also contained Treponema spp. and D. nodosus, and were histopathologically categorized as subclinical DD. Another eighteen of the "healthy" skin samples showed serious epidermal hyperplasia but were not colonized by bacteria while only four samples were found normal. We hypothesise that external noxious stimuli allow D. nodosus to break down the epidermal barrier creating a suitable environment for the secondary invaders, Treponema species, which gradually take over the infection site. The variety and different distribution of treponemes in the DD lesions observed in this study, suggests that most of the Treponema phylotypes have the potential to be pathogenic.
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Affiliation(s)
- Marianne Rasmussen
- Technical University of Denmark, National Veterinary Institute, Copenhagen, Denmark
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Klitgaard K, Friis C, Jensen TK, Angen Ø, Boye M. Transcriptional portrait of Actinobacillus pleuropneumoniae during acute disease--potential strategies for survival and persistence in the host. PLoS One 2012; 7:e35549. [PMID: 22530048 PMCID: PMC3328466 DOI: 10.1371/journal.pone.0035549] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/21/2012] [Indexed: 11/24/2022] Open
Abstract
Background Gene expression profiles of bacteria in their natural hosts can provide novel insight into the host-pathogen interactions and molecular determinants of bacterial infections. In the present study, the transcriptional profile of the porcine lung pathogen Actinobacillus pleuropneumoniae was monitored during the acute phase of infection in its natural host. Methodology/Principal Findings Bacterial expression profiles of A. pleuropneumoniae isolated from lung lesions of 25 infected pigs were compared in samples taken 6, 12, 24 and 48 hours post experimental challenge. Within 6 hours, focal, fibrino hemorrhagic lesions could be observed in the pig lungs, indicating that A. pleuropneumoniae had managed to establish itself successfully in the host. We identified 237 differentially regulated genes likely to encode functions required by the bacteria for colonization and survival in the host. This group was dominated by genes involved in various aspects of energy metabolism, especially anaerobic respiration and carbohydrate metabolism. Remodeling of the bacterial envelope and modifications of posttranslational processing of proteins also appeared to be of importance during early infection. The results suggested that A. pleuropneumoniae is using various strategies to increase its fitness, such as applying Na+ pumps as an alternative way of gaining energy. Furthermore, the transcriptional data provided potential clues as to how A. pleuropneumoniae is able to circumvent host immune factors and survive within the hostile environment of host macrophages. This persistence within macrophages may be related to urease activity, mobilization of various stress responses and active evasion of the host defenses by cell surface sialylation. Conclusions/Significance The data presented here highlight the importance of metabolic adjustments to host conditions as virulence factors of infecting microorganisms and help to provide insight into the mechanisms behind the efficient colonization and persistence of A. pleuropneumoniae during acute disease.
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Affiliation(s)
- Kirstine Klitgaard
- National Veterinary Institute, Technical University of Denmark, Frederiksberg C, Denmark.
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26
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Klitgaard K, Friis C, Angen O, Boye M. Comparative profiling of the transcriptional response to iron restriction in six serotypes of Actinobacillus pleuropneumoniae with different virulence potential. BMC Genomics 2010; 11:698. [PMID: 21143895 PMCID: PMC3091793 DOI: 10.1186/1471-2164-11-698] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 12/09/2010] [Indexed: 01/16/2023] Open
Abstract
Background Comparative analysis of gene expression among serotypes within a species can provide valuable information on important differences between related genomes. For the pig lung pathogen Actinobacillus pleuropneumoniae, 15 serotypes with a considerable variation in virulence potential and immunogenicity have been identified. This serotypic diversity can only partly be explained by amount of capsule and differences in the RTX toxin genes in their genomes. Iron acquisition in vivo is an important bacterial function and in pathogenic bacteria, iron-limitation is often a signal for the induction of virulence genes. We used a pan-genomic microarray to study the transcriptional response to iron restriction in vitro in six serotypes of A. pleuropneumoniae (1, 2, 3, 5b, 6, and 7), representing at least two levels of virulence. Results In total, 45 genes were significantly (p < 0.0001) up-regulated and 67 genes significantly down-regulated in response to iron limitation. Not previously observed in A. pleuropneumoniae was the up-regulation of a putative cirA-like siderophore in all six serotypes. Three genes, recently described in A. pleuropneumoniae as possibly coding for haemoglobin-haptoglobin binding proteins, displayed significant serotype related up-regulation to iron limitation. For all three genes, the expression appeared at its lowest in serotype 3, which is generally considered one of the least virulent serotypes of A. pleuropneumoniae. The three genes share homology with the hmbR haemoglobin receptor of Neisseria meningitidis, a possible virulence factor which contributes to bacterial survival in rats. Conclusions By comparative analysis of gene expression among 6 different serotypes of A. pleuropneumoniae we identified a common set of presumably essential core genes, involved in iron regulation. The results support and expand previous observations concerning the identification of new potential iron acquisition systems in A. pleuropneumoniae, showing that this bacterium has evolved several strategies for scavenging the limited iron resources of the host. The combined effect of iron-depletion and serotype proved to be modest, indicating that serotypes of both moderate and high virulence at least in vitro are reacting almost identical to iron restriction. One notable exception, however, is the haemoglobin-haptoglobin binding protein cluster which merits further investigation.
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Affiliation(s)
- Kirstine Klitgaard
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, DK-1790, Copenhagen, Denmark.
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Klitgaard K, Jensen TK, Angen Ø, Boye M. Measurement of bacterial gene expression in vivo by laser capture microdissection and quantitative real-time RT-PCR. J Microbiol Methods 2007; 69:414-6. [PMID: 17250913 DOI: 10.1016/j.mimet.2006.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 11/28/2006] [Accepted: 12/01/2006] [Indexed: 11/16/2022]
Abstract
Due to the relative small number of bacterial pathogens present in an infected host, exploration of pathogen gene expression in vivo is challenging. This study reports the development of a protocol for quantifying bacterial gene expression in vivo in Actinobacillus pleuropneumoniae using laser capture microdissection and real-time quantitative RT-PCR.
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Affiliation(s)
- Kirstine Klitgaard
- National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, DK-1790 Copenhagen V, Denmark
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Mølbak L, Klitgaard K, Jensen TK, Fossi M, Boye M. Identification of a novel, invasive, not-yet-cultivated Treponema sp. in the large intestine of pigs by PCR amplification of the 16S rRNA gene. J Clin Microbiol 2006; 44:4537-40. [PMID: 17005743 PMCID: PMC1698379 DOI: 10.1128/jcm.01537-06] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Laser capture microdissection in combination with fluorescent in situ hybridization was used to identify an unknown species of spirochetes from the pig colonic mucosa. The 16S rRNA gene was PCR amplified, and the closest related type strain was Treponema bryantiiT (90.1%). The spirochete, here named "Candidatus Treponema suis," was associated with colitis, including invasion of the surface epithelium as well as superficial parts of the mucosa.
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MESH Headings
- Animals
- Colitis/microbiology
- Colitis/veterinary
- Colon/microbiology
- DNA, Bacterial/analysis
- DNA, Bacterial/genetics
- DNA, Ribosomal/analysis
- DNA, Ribosomal/genetics
- Genes, rRNA
- In Situ Hybridization, Fluorescence
- Intestinal Mucosa/microbiology
- Microdissection/methods
- Molecular Sequence Data
- Phylogeny
- Polymerase Chain Reaction
- RNA, Ribosomal, 16S/genetics
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
- Swine/microbiology
- Swine Diseases/microbiology
- Treponema/classification
- Treponema/genetics
- Treponema/isolation & purification
- Treponemal Infections/microbiology
- Treponemal Infections/veterinary
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Affiliation(s)
- Lars Mølbak
- Danish Institute for Food and Veterinary Research, Bülowsvej 27, DK-1790 Copenhagen V, Denmark.
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Klitgaard K, Mølbak L, Jensen TK, Lindboe CF, Boye M. Laser capture microdissection of bacterial cells targeted by fluorescence in situ hybridization. Biotechniques 2005; 39:864-8. [PMID: 16382905 DOI: 10.2144/000112024] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Direct cultivation-independent sequence retrieval of unidentified bacteria from histological tissue sections has been limited by the difficulty of selectively isolating specific bacteria from a complex environment. Here, a new DNA isolation approach is presented for prokaryotic cells. By this method, a potentially pathogenic strain of the genus Brachyspira from formalin-fixed human colonic biopsies were visualized by fluorescence in situ hybridization (FISH) with a 16S rRNA-targeting oligonucleotide probe, followed by laser capture microdissection (LCM) of the targeted cells. Direct 16S rRNA gene PCR was performed from the dissected microcolonies, and the subsequent DNA sequence analysis identified the dissected bacterial cells as belonging to the Brachyspira aalborgi cluster 1. The advantage of this technique is the ability to combine the histological recognition of the specific bacteria within the tissue with molecular analysis of 16S rRNA gene or other genes of interest. This method is widely applicable for the identification of noncultivable bacteria and their gene pool from formalin-fixed paraffin-embedded tissue samples.
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