Christina Ahlstrom, Ph.D.
Christina is a Research Biologist for the Alaska Science Center.
My research aims to better understand wildlife and zoonotic diseases in Alaska and adjacent regions. I use molecular tools to investigate the genetic diversity and transmission pathways of pathogens in wildlife populations and the ecosystems they occupy. My main research topics include antimicrobial resistance in wild birds, avian influenza, and Giardia and Cryptosporidium parasites in Arctic Alaska. I strive to achieve a more comprehensive understanding of where pathogens are detected and their genetic relatedness among spatio-temporally diverse populations to help inform management actions aimed to interrupt transmission pathways.
Professional Experience
2024 - Present Research Biologist, USGS Alaska Science Center, Anchorage, Alaska
2017 - 2023 Geneticist, USGS Alaska Science Center, Anchorage, Alaska
2015 - 2017 Consultant Epidemiologist & Data Analyst, Epi-interactive, Wellington, New Zealand
2017 Molecular Epidemiology Consultant, Food and Agriculture Organisation, Rome, Italy
2016 Molecular Epidemiology Consultant, Food and Agriculture Organisation, Rome, Italy
2005 - 2008 Seasonal Research Assistant, Quality Milk Production Services, Cornell University, Ithaca, NY
Education and Certifications
Ph.D. 2015 University of Calgary, Calgary, Alberta, Canada Veterinary Medical Sciences
M.S. 2011 Colorado State University, Fort Collins, CO Animal Science
B.S. 2008 University at Buffalo, Buffalo, NY Biology
Science and Products
Filter Total Items: 15
Data for Infectivity of Wild-Bird Origin Influenza A Viruses in Minnesota Wetlands Across Seasons Data for Infectivity of Wild-Bird Origin Influenza A Viruses in Minnesota Wetlands Across Seasons
This data set represents an ecological and laboratory-based experiment to understand influenza virus viability in surface water. Data tables included in this release consist of 1) daily mean water temperature, 2) viability of viruses maintained in water, 3) influenza detection in duck samples, 4) viral titers of experimentally inoculated water samples, and 5) water chemistry.
Molecular Detection and Characterization of Highly Pathogenic H5N1 Avian Influenza Viruses in Wild Birds Inhabiting Western Alaska Provides Evidence for Three Independent Viral Introductions Molecular Detection and Characterization of Highly Pathogenic H5N1 Avian Influenza Viruses in Wild Birds Inhabiting Western Alaska Provides Evidence for Three Independent Viral Introductions
This data set describes three independent viral introductions of Highly pathogenic H5N1 avian influenza viruses into Alaska.
Antimicrobial resistance testing, and qPCR detection of antimicrobial resistance genes in surface water and gull (Larus spp.) feces on the Kenai Peninsula, Alaska, 2021 Antimicrobial resistance testing, and qPCR detection of antimicrobial resistance genes in surface water and gull (Larus spp.) feces on the Kenai Peninsula, Alaska, 2021
This data set includes information on collections of surface water and fecal samples from wild gulls (Larus spp.) at two locations on the Kenai Peninsula, Alaska, USA. Samples were screened for Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) and tested for resistance to multiple antibiotics.
Tracking Data for Three Large-bodied Gull Species and Hybrids (Larus spp.) Tracking Data for Three Large-bodied Gull Species and Hybrids (Larus spp.)
This data release includes 2 child items with tracking data for three large-bodied gull species and hybrids (Larus species) utilizing coastal areas of Alaska. Child Item 1: "Argos and GPS Satellite Tracking Data for Three Large-Bodied Gull Species and Hybrids (Larus spp.) - Processed Data" -- Quality-controlled data collected from Argos and Argos-linked GPS satellite transmitters.
Data for Continental-Scale Dispersal of Antimicrobial Resistant Bacteria by Alaska Landfill-Foraging Gulls Data for Continental-Scale Dispersal of Antimicrobial Resistant Bacteria by Alaska Landfill-Foraging Gulls
This data set includes information on collections of fecal samples from wild gulls (Larus spp.) at seven locations in Alaska, USA. Samples were screened for Escherichia coli (E. coli) and tested for resistance to multiple antibiotics.
Sampling, Antimicrobial Resistance Testing, and Genomic Typing of Carbapenemase Producing E. coli in Gulls (Larus spp.) in Alaska, 2016 Sampling, Antimicrobial Resistance Testing, and Genomic Typing of Carbapenemase Producing E. coli in Gulls (Larus spp.) in Alaska, 2016
This data set includes information on collections of fecal samples from wild gulls (Larus spp.) at seven locations in Alaska, USA. Samples were screened for carbapenemase producing Escherichia coli (E. coli) and tested for resistance to multiple antibiotics.
Filter Total Items: 20
Exchange of carbapenem-resistant Escherichia coli Sequence Type 38 intercontinentally and among wild bird, human, and environmental niches Exchange of carbapenem-resistant Escherichia coli Sequence Type 38 intercontinentally and among wild bird, human, and environmental niches
Carbapenem-resistant Enterobacteriaceae (CRE) are a global threat to human health and are increasingly being isolated from nonclinical settings. OXA-48-producing Escherichia coli sequence type 38 (ST38) is the most frequently reported CRE type in wild birds and has been detected in gulls or storks in North America, Europe, Asia, and Africa. The epidemiology and evolution of CRE in...
Authors
Christina Ahlstrom, Hanna Woksepp, Linus Sandegren, Andrew M. Ramey, Jonas Bonnedahl
Antibiotic resistance in free-ranging wildlife Antibiotic resistance in free-ranging wildlife
In this chapter, we provide an overview of antimicrobial resistant (AMR) bacteria in wildlife through the presentation of general trends of occurrence among both captive and free-ranging wild animal populations, discussion of importance to human health and wildlife conservation, and identification of priority areas for future research and monitoring efforts. Once most commonly identified...
Authors
Andrew M. Ramey, Christina Ahlstrom
Maintenance and dissemination of avian-origin influenza A virus within the northern Atlantic Flyway of North America Maintenance and dissemination of avian-origin influenza A virus within the northern Atlantic Flyway of North America
Wild waterbirds, the natural reservoirs for avian influenza viruses, undergo migratory movements each year, connecting breeding and wintering grounds within broad corridors known as flyways. In a continental or global view, the study of virus movements within and across flyways is important to understanding virus diversity, evolution, and movement. From 2015 to 2017, we sampled waterfowl...
Authors
Diann Prosser, Jiani Chen, Christina Ahlstrom, Andrew B. Reeves, Rebecca L. Poulson, Jeffery D. Sullivan, Daniel McAuley, Carl R. Callahan, Peter C. McGowan, Justin Bahl, David E. Stallknecht, Andrew M. Ramey
Genomically diverse carbapenem resistant Enterobacteriaceae from wild birds provide insight into global patterns of spatiotemporal dissemination Genomically diverse carbapenem resistant Enterobacteriaceae from wild birds provide insight into global patterns of spatiotemporal dissemination
Carbapenem resistant Enterobacteriaceae (CRE) are a threat to public health globally, yet the role of the environment in the epidemiology of CRE remains elusive. Given that wild birds can acquire CRE, likely from foraging in anthropogenically impacted areas, and may aid in the maintenance and dissemination of CRE in the environment, a spatiotemporal comparison of isolates from different...
Authors
Christina Ahlstrom, Hanna Woksepp, Linus Sandegren, Mashkoor Mohsin, Badrul Hasan, Denys Muzyka, Jorge Hernandez, Filip Aguirre, Atalay Tok, Jan Soderman, Bjorn Olsen, Andrew M. Ramey, Jonas Bonnedahl
Genomic comparison of carbapenem-resistant Enterobacteriaceae from humans and gulls in Alaska Genomic comparison of carbapenem-resistant Enterobacteriaceae from humans and gulls in Alaska
Objectives Wildlife may harbor clinically important antimicrobial resistant (AMR) bacteria, but the role of wildlife in the epidemiology of AMR bacterial infections in humans is largely unknown. In this study, we aimed to assess dissemination of theblaKPC carbapenemase gene among humans and gulls in Alaska.Methods We performed whole genome sequencing to determine the genetic context...
Authors
Christina Ahlstrom, Anna Frick, Catherine Pongratz, Kimberly Spink, Catherine Xavier, Jonas Bonnedahl, Andrew M. Ramey
Evidence for continental-scale dispersal of antimicrobial resistant bacteria by landfill-foraging gulls Evidence for continental-scale dispersal of antimicrobial resistant bacteria by landfill-foraging gulls
Anthropogenic inputs into the environment may serve as sources of antimicrobial resistant bacteria and alter the ecology and population dynamics of synanthropic wild animals by providing supplemental forage. In this study, we used a combination of phenotypic and genomic approaches to characterize antimicrobial resistant indicator bacteria, animal telemetry to describe host movement...
Authors
Christina Ahlstrom, Marielle L. van Toor, Hanna Woksepp, Jeffrey C Chandler, John Reed, Andrew B. Reeves, Jonas Waldenström, Alan B. Franklin, David C. Douglas, Jonas Bonnedahl, Andrew M. Ramey
Non-USGS Publications**
Muellner, U., G. Fournie, P. Muellner, C. A. Ahlstrom, and D. U. Pfeiffer. 2018. Epidemix - an Interactive Multi-Model Application for Teaching and Visualizing Infectious Disease Transmission. Epidemics 23:49-54. doi:10.1016/j.epidem.2017.12.003.
Ahlstrom, C. A., P. Muellner, G. Lammers, M. Jones, S. Octavia, R. Lan, and J. Heller. 2017. Shiga-toxin producing E. coli O157 shedding dynamics in an Australian beef herd. Frontiers in Veterinary Science 4:200. doi:10.3389/fvets.2017.00200.
Ahlstrom, C. A., C. S. Manuel, H. C. Den Bakker, M. Wiedmann, and K. K. Nightingale. 2017. Molecular Ecology of Listeria spp., Salmonella, Escherichia coli O157:H7, and non-O157 Shiga Toxin Producing Escherichia coli in Pristine Natural Environments in Northern Colorado. Journal of Applied Microbiology. doi:10.1111/jam.13657.
Ahlstrom, C. A., P. Muellner, S. Spencer, S. Hong, A. Saupe, A. Rovira, C. Hedberg, A. Perez, and J. Alvarez. 2017. Inferring source attribution from a multi-year multi-source dataset of Salmonella in Minnesota. Zoonoses and Public Health 64(8):589-598. doi:10.1111/zph.12351.
Bauman, C. A., A. Jones-Bitton, C. A. Ahlstrom, L. Mutharia, J. De Buck, J. Jansen, D. F. Kelton, and P. Menzies. 2017. Identification of Mycobacterium avium ssp. paratuberculosis strains isolated from dairy goats and dairy sheep in Ontario, Canada. Canadian Journal of Veterinary Research 81(4):304-307.
Hong, S., A. Rovira, P. Davies, C. A. Ahlstrom, P. Muellner, A. Rendahl, K. Olsen, J. B. Bender, S. Wells, A. Perez, and J. Alvarez. 2016. Serotypes and antimicrobial resistance in Salmonella enterica recovered from clinical samples from cattle and swine in Minnesota, 2006 to 2015. International Journal of Parasitology: Parasites and Wildlife 11(12):e0168016. doi:10.1371/journal.pone.0168016.
Muellner, P., U. Muellner, M. C. Gates, T. Pearce, C. A. Ahlstrom, D. O'Neill, D. Brodbelt, and N. J. Cave. 2016. Evidence in Practice – A Pilot Study Leveraging Companion Animal and Equine Health Data from Primary Care Veterinary Clinics in New Zealand. Frontiers in Veterinary Science 3:116. doi:10.3389/fvets.2016.00116.
Davidson, F., C. A. Ahlstrom, J. De Buck, H. G. Whitney, and K. Tahlan. 2016. Examination of Mycobacterium avium subspecies paratuberculosis mixed genotype infections in dairy animals using a whole genome sequencing approach. PeerJ 4:e2793. doi:10.7717/peerj.2793.
Ahlstrom, C. A., H. W. Barkema, and J. De Buck. 2016. Relative frequency of 4 major strain types of Mycobacterium avium ssp. paratuberculosis in Canadian dairy herds using a novel single nucleotide polymorphism-based polymerase chain reaction. Journal of Dairy Science 99(10):8297-8303. doi:10.3168/jds.2016-11397.
Ahlstrom, C. A., H. W. Barkema, K. Stevenson, R. N. Zadoks, R. Biek, R. Kao, H. Trewby, D. Haupstein, D. F. Kelton, G. Fecteau, O. Labrecque, G. P. Keefe, S. L. B. McKenna, K. Tahlan, and J. De Buck. 2016. Genome-wide diversity and phylogeography of Mycobacterium avium subsp. paratuberculosis in Canadian dairy cattle. PLoS One 11:e0149017. doi:10.1371/journal.pone.0149017.
Ahlstrom, C. A., H. W. Barkema, K. Stevenson, R. N. Zadoks, R. Biek, R. Kao, H. Trewby, S. Hendrick, D. Haupstein, D. F. Kelton, G. Fecteau, O. Labrecque, G. P. Keefe, S. L. B. McKenna, and J. De Buck. 2015. Limitations of variable number of tandem repeat typing identified through whole genome sequencing of Mycobacterium avium subsp. paratuberculosis on a national and herd level. BMC Genomics 16:161. doi:10.1186/s12864-015-1387-6.
Den Bakker, H. C., S. Warchocki, E. M. Wright, A. F. Allred, C. A. Ahlstrom, C. S. Manuel, M. J. Stasiewicz, A. Burrell, S. Roof, L. Strawn, E. D. Fortes, K. K. Nightingale, D. Kephart, and M. Wiedmann. 2014. Listeria floridensis sp. nov., Listeria aquatica sp. nov., Listeria cornellensis sp. nov., Listeria riparia sp. nov., and Listeria grandensis sp. nov., from agricultural and natural environments. International Journal of Systematic and Evolutionary Microbiology 64:1882-1889. doi:10.1099/ijs.0.052720-0.
Ahlstrom, C. A., H. W. Barkema, and J. De Buck. 2014. Improved Short-Sequence-Repeat Genotyping of Mycobacterium avium subsp. paratuberculosis by Using Matrix-Assisted Laser Desorption Ionization—Time of Flight Mass Spectrometry. Applied and Environmental Microbiology 80:534-539. doi:10.1128/AEM.03212-13.
Zadoks, R. N., H. M. Griffiths, M. A. Munoz, C. A. Ahlstrom, G. J. Bennett, E. Thomas, and Y. H. Schukken. 2011. Sources of Klebsiella and Raoultella species on dairy farms: be careful where you walk. Journal of Dairy Science 94(2):1045-1051. doi:10.3168/jds.2010-3603.
Munoz, M. A., G. J. Bennett, C. A. Ahlstrom, H. M. Griffiths, Y. H. Schukken, and R. N. Zadoks. 2008. Cleanliness Scores as Indicator of Klebsiella Exposure in Dairy Cows. Journal of Dairy Science 91(10):3908-3916. doi:10.3168/jds.2008-1090.
Munoz, M. A., C. A. Ahlstrom, B. J. Rauch, and R. N. Zadoks. 2006. Fecal Shedding of Klebsiella pneumoniae by Dairy Cows. Journal of Dairy Science 89(9):3425-3430. doi:10.3168/jds.S0022-0302(06)72379-7.
Muellner, P., D. Hodges, C. A. Ahlstrom, M. Newman, R. Davidson, D. U. Pfeiffer, J. Marshall, and C. Morley. 2018. Creating a framework for the prioritization of biosecurity risks to the New Zealand dairy industry. Transboundary and Emerging Diseases 65(4):1067-1077. doi:10.1111/tbed.12848.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 15
Data for Infectivity of Wild-Bird Origin Influenza A Viruses in Minnesota Wetlands Across Seasons Data for Infectivity of Wild-Bird Origin Influenza A Viruses in Minnesota Wetlands Across Seasons
This data set represents an ecological and laboratory-based experiment to understand influenza virus viability in surface water. Data tables included in this release consist of 1) daily mean water temperature, 2) viability of viruses maintained in water, 3) influenza detection in duck samples, 4) viral titers of experimentally inoculated water samples, and 5) water chemistry.
Molecular Detection and Characterization of Highly Pathogenic H5N1 Avian Influenza Viruses in Wild Birds Inhabiting Western Alaska Provides Evidence for Three Independent Viral Introductions Molecular Detection and Characterization of Highly Pathogenic H5N1 Avian Influenza Viruses in Wild Birds Inhabiting Western Alaska Provides Evidence for Three Independent Viral Introductions
This data set describes three independent viral introductions of Highly pathogenic H5N1 avian influenza viruses into Alaska.
Antimicrobial resistance testing, and qPCR detection of antimicrobial resistance genes in surface water and gull (Larus spp.) feces on the Kenai Peninsula, Alaska, 2021 Antimicrobial resistance testing, and qPCR detection of antimicrobial resistance genes in surface water and gull (Larus spp.) feces on the Kenai Peninsula, Alaska, 2021
This data set includes information on collections of surface water and fecal samples from wild gulls (Larus spp.) at two locations on the Kenai Peninsula, Alaska, USA. Samples were screened for Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) and tested for resistance to multiple antibiotics.
Tracking Data for Three Large-bodied Gull Species and Hybrids (Larus spp.) Tracking Data for Three Large-bodied Gull Species and Hybrids (Larus spp.)
This data release includes 2 child items with tracking data for three large-bodied gull species and hybrids (Larus species) utilizing coastal areas of Alaska. Child Item 1: "Argos and GPS Satellite Tracking Data for Three Large-Bodied Gull Species and Hybrids (Larus spp.) - Processed Data" -- Quality-controlled data collected from Argos and Argos-linked GPS satellite transmitters.
Data for Continental-Scale Dispersal of Antimicrobial Resistant Bacteria by Alaska Landfill-Foraging Gulls Data for Continental-Scale Dispersal of Antimicrobial Resistant Bacteria by Alaska Landfill-Foraging Gulls
This data set includes information on collections of fecal samples from wild gulls (Larus spp.) at seven locations in Alaska, USA. Samples were screened for Escherichia coli (E. coli) and tested for resistance to multiple antibiotics.
Sampling, Antimicrobial Resistance Testing, and Genomic Typing of Carbapenemase Producing E. coli in Gulls (Larus spp.) in Alaska, 2016 Sampling, Antimicrobial Resistance Testing, and Genomic Typing of Carbapenemase Producing E. coli in Gulls (Larus spp.) in Alaska, 2016
This data set includes information on collections of fecal samples from wild gulls (Larus spp.) at seven locations in Alaska, USA. Samples were screened for carbapenemase producing Escherichia coli (E. coli) and tested for resistance to multiple antibiotics.
Filter Total Items: 20
Exchange of carbapenem-resistant Escherichia coli Sequence Type 38 intercontinentally and among wild bird, human, and environmental niches Exchange of carbapenem-resistant Escherichia coli Sequence Type 38 intercontinentally and among wild bird, human, and environmental niches
Carbapenem-resistant Enterobacteriaceae (CRE) are a global threat to human health and are increasingly being isolated from nonclinical settings. OXA-48-producing Escherichia coli sequence type 38 (ST38) is the most frequently reported CRE type in wild birds and has been detected in gulls or storks in North America, Europe, Asia, and Africa. The epidemiology and evolution of CRE in...
Authors
Christina Ahlstrom, Hanna Woksepp, Linus Sandegren, Andrew M. Ramey, Jonas Bonnedahl
Antibiotic resistance in free-ranging wildlife Antibiotic resistance in free-ranging wildlife
In this chapter, we provide an overview of antimicrobial resistant (AMR) bacteria in wildlife through the presentation of general trends of occurrence among both captive and free-ranging wild animal populations, discussion of importance to human health and wildlife conservation, and identification of priority areas for future research and monitoring efforts. Once most commonly identified...
Authors
Andrew M. Ramey, Christina Ahlstrom
Maintenance and dissemination of avian-origin influenza A virus within the northern Atlantic Flyway of North America Maintenance and dissemination of avian-origin influenza A virus within the northern Atlantic Flyway of North America
Wild waterbirds, the natural reservoirs for avian influenza viruses, undergo migratory movements each year, connecting breeding and wintering grounds within broad corridors known as flyways. In a continental or global view, the study of virus movements within and across flyways is important to understanding virus diversity, evolution, and movement. From 2015 to 2017, we sampled waterfowl...
Authors
Diann Prosser, Jiani Chen, Christina Ahlstrom, Andrew B. Reeves, Rebecca L. Poulson, Jeffery D. Sullivan, Daniel McAuley, Carl R. Callahan, Peter C. McGowan, Justin Bahl, David E. Stallknecht, Andrew M. Ramey
Genomically diverse carbapenem resistant Enterobacteriaceae from wild birds provide insight into global patterns of spatiotemporal dissemination Genomically diverse carbapenem resistant Enterobacteriaceae from wild birds provide insight into global patterns of spatiotemporal dissemination
Carbapenem resistant Enterobacteriaceae (CRE) are a threat to public health globally, yet the role of the environment in the epidemiology of CRE remains elusive. Given that wild birds can acquire CRE, likely from foraging in anthropogenically impacted areas, and may aid in the maintenance and dissemination of CRE in the environment, a spatiotemporal comparison of isolates from different...
Authors
Christina Ahlstrom, Hanna Woksepp, Linus Sandegren, Mashkoor Mohsin, Badrul Hasan, Denys Muzyka, Jorge Hernandez, Filip Aguirre, Atalay Tok, Jan Soderman, Bjorn Olsen, Andrew M. Ramey, Jonas Bonnedahl
Genomic comparison of carbapenem-resistant Enterobacteriaceae from humans and gulls in Alaska Genomic comparison of carbapenem-resistant Enterobacteriaceae from humans and gulls in Alaska
Objectives Wildlife may harbor clinically important antimicrobial resistant (AMR) bacteria, but the role of wildlife in the epidemiology of AMR bacterial infections in humans is largely unknown. In this study, we aimed to assess dissemination of theblaKPC carbapenemase gene among humans and gulls in Alaska.Methods We performed whole genome sequencing to determine the genetic context...
Authors
Christina Ahlstrom, Anna Frick, Catherine Pongratz, Kimberly Spink, Catherine Xavier, Jonas Bonnedahl, Andrew M. Ramey
Evidence for continental-scale dispersal of antimicrobial resistant bacteria by landfill-foraging gulls Evidence for continental-scale dispersal of antimicrobial resistant bacteria by landfill-foraging gulls
Anthropogenic inputs into the environment may serve as sources of antimicrobial resistant bacteria and alter the ecology and population dynamics of synanthropic wild animals by providing supplemental forage. In this study, we used a combination of phenotypic and genomic approaches to characterize antimicrobial resistant indicator bacteria, animal telemetry to describe host movement...
Authors
Christina Ahlstrom, Marielle L. van Toor, Hanna Woksepp, Jeffrey C Chandler, John Reed, Andrew B. Reeves, Jonas Waldenström, Alan B. Franklin, David C. Douglas, Jonas Bonnedahl, Andrew M. Ramey
Non-USGS Publications**
Muellner, U., G. Fournie, P. Muellner, C. A. Ahlstrom, and D. U. Pfeiffer. 2018. Epidemix - an Interactive Multi-Model Application for Teaching and Visualizing Infectious Disease Transmission. Epidemics 23:49-54. doi:10.1016/j.epidem.2017.12.003.
Ahlstrom, C. A., P. Muellner, G. Lammers, M. Jones, S. Octavia, R. Lan, and J. Heller. 2017. Shiga-toxin producing E. coli O157 shedding dynamics in an Australian beef herd. Frontiers in Veterinary Science 4:200. doi:10.3389/fvets.2017.00200.
Ahlstrom, C. A., C. S. Manuel, H. C. Den Bakker, M. Wiedmann, and K. K. Nightingale. 2017. Molecular Ecology of Listeria spp., Salmonella, Escherichia coli O157:H7, and non-O157 Shiga Toxin Producing Escherichia coli in Pristine Natural Environments in Northern Colorado. Journal of Applied Microbiology. doi:10.1111/jam.13657.
Ahlstrom, C. A., P. Muellner, S. Spencer, S. Hong, A. Saupe, A. Rovira, C. Hedberg, A. Perez, and J. Alvarez. 2017. Inferring source attribution from a multi-year multi-source dataset of Salmonella in Minnesota. Zoonoses and Public Health 64(8):589-598. doi:10.1111/zph.12351.
Bauman, C. A., A. Jones-Bitton, C. A. Ahlstrom, L. Mutharia, J. De Buck, J. Jansen, D. F. Kelton, and P. Menzies. 2017. Identification of Mycobacterium avium ssp. paratuberculosis strains isolated from dairy goats and dairy sheep in Ontario, Canada. Canadian Journal of Veterinary Research 81(4):304-307.
Hong, S., A. Rovira, P. Davies, C. A. Ahlstrom, P. Muellner, A. Rendahl, K. Olsen, J. B. Bender, S. Wells, A. Perez, and J. Alvarez. 2016. Serotypes and antimicrobial resistance in Salmonella enterica recovered from clinical samples from cattle and swine in Minnesota, 2006 to 2015. International Journal of Parasitology: Parasites and Wildlife 11(12):e0168016. doi:10.1371/journal.pone.0168016.
Muellner, P., U. Muellner, M. C. Gates, T. Pearce, C. A. Ahlstrom, D. O'Neill, D. Brodbelt, and N. J. Cave. 2016. Evidence in Practice – A Pilot Study Leveraging Companion Animal and Equine Health Data from Primary Care Veterinary Clinics in New Zealand. Frontiers in Veterinary Science 3:116. doi:10.3389/fvets.2016.00116.
Davidson, F., C. A. Ahlstrom, J. De Buck, H. G. Whitney, and K. Tahlan. 2016. Examination of Mycobacterium avium subspecies paratuberculosis mixed genotype infections in dairy animals using a whole genome sequencing approach. PeerJ 4:e2793. doi:10.7717/peerj.2793.
Ahlstrom, C. A., H. W. Barkema, and J. De Buck. 2016. Relative frequency of 4 major strain types of Mycobacterium avium ssp. paratuberculosis in Canadian dairy herds using a novel single nucleotide polymorphism-based polymerase chain reaction. Journal of Dairy Science 99(10):8297-8303. doi:10.3168/jds.2016-11397.
Ahlstrom, C. A., H. W. Barkema, K. Stevenson, R. N. Zadoks, R. Biek, R. Kao, H. Trewby, D. Haupstein, D. F. Kelton, G. Fecteau, O. Labrecque, G. P. Keefe, S. L. B. McKenna, K. Tahlan, and J. De Buck. 2016. Genome-wide diversity and phylogeography of Mycobacterium avium subsp. paratuberculosis in Canadian dairy cattle. PLoS One 11:e0149017. doi:10.1371/journal.pone.0149017.
Ahlstrom, C. A., H. W. Barkema, K. Stevenson, R. N. Zadoks, R. Biek, R. Kao, H. Trewby, S. Hendrick, D. Haupstein, D. F. Kelton, G. Fecteau, O. Labrecque, G. P. Keefe, S. L. B. McKenna, and J. De Buck. 2015. Limitations of variable number of tandem repeat typing identified through whole genome sequencing of Mycobacterium avium subsp. paratuberculosis on a national and herd level. BMC Genomics 16:161. doi:10.1186/s12864-015-1387-6.
Den Bakker, H. C., S. Warchocki, E. M. Wright, A. F. Allred, C. A. Ahlstrom, C. S. Manuel, M. J. Stasiewicz, A. Burrell, S. Roof, L. Strawn, E. D. Fortes, K. K. Nightingale, D. Kephart, and M. Wiedmann. 2014. Listeria floridensis sp. nov., Listeria aquatica sp. nov., Listeria cornellensis sp. nov., Listeria riparia sp. nov., and Listeria grandensis sp. nov., from agricultural and natural environments. International Journal of Systematic and Evolutionary Microbiology 64:1882-1889. doi:10.1099/ijs.0.052720-0.
Ahlstrom, C. A., H. W. Barkema, and J. De Buck. 2014. Improved Short-Sequence-Repeat Genotyping of Mycobacterium avium subsp. paratuberculosis by Using Matrix-Assisted Laser Desorption Ionization—Time of Flight Mass Spectrometry. Applied and Environmental Microbiology 80:534-539. doi:10.1128/AEM.03212-13.
Zadoks, R. N., H. M. Griffiths, M. A. Munoz, C. A. Ahlstrom, G. J. Bennett, E. Thomas, and Y. H. Schukken. 2011. Sources of Klebsiella and Raoultella species on dairy farms: be careful where you walk. Journal of Dairy Science 94(2):1045-1051. doi:10.3168/jds.2010-3603.
Munoz, M. A., G. J. Bennett, C. A. Ahlstrom, H. M. Griffiths, Y. H. Schukken, and R. N. Zadoks. 2008. Cleanliness Scores as Indicator of Klebsiella Exposure in Dairy Cows. Journal of Dairy Science 91(10):3908-3916. doi:10.3168/jds.2008-1090.
Munoz, M. A., C. A. Ahlstrom, B. J. Rauch, and R. N. Zadoks. 2006. Fecal Shedding of Klebsiella pneumoniae by Dairy Cows. Journal of Dairy Science 89(9):3425-3430. doi:10.3168/jds.S0022-0302(06)72379-7.
Muellner, P., D. Hodges, C. A. Ahlstrom, M. Newman, R. Davidson, D. U. Pfeiffer, J. Marshall, and C. Morley. 2018. Creating a framework for the prioritization of biosecurity risks to the New Zealand dairy industry. Transboundary and Emerging Diseases 65(4):1067-1077. doi:10.1111/tbed.12848.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.