title: Differences in intermittent and continuous fecal shedding patterns between natural and experimental Mycobacterium avium subspecies paratuberculosis infections in cattle.
abstract: The objective of this paper is to study shedding patterns of cows infected with Mycobacterium avium subsp. paratuberculosis (MAP). While multiple single farm studies of MAP dynamics were reported, there is not large scale meta-analysis of both natural and experimental infections. Large difference in shedding patterns between experimentally and naturally infected cows were observed. Experimental infections are thus probably driven by different pathological mechanisms. For further evaluations of shedding patterns only natural infections were used. Within such infections, the transition to high shedding was studied as a proxy to the development of a clinical disease. The majority of studied cows never developed high shedding levels. Those that do, typically never reduced their shedding level to low or no shedding. Cows that eventually became high shedders showed a pattern of continuous shedding. In contrast, cows with an intermittent shedding pattern had a low probability to ever become high shedders. In addition, cows that start shedding at a younger age (less than three years of age) have a lower hazard of becoming high shedders compared to cows starting to shed at an older age. These data suggest the presence of three categories of immune control. Cows that are intermittent shedders have the infection process under control (no progressive infection). Cows that start shedding persistently at a young age partially control the infection, but eventually will be high shedders (slow progressive infection), while cows that start shedding persistently at an older age cannot effectively control the infection and become high shedders rapidly.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia. rmm257@gmail.com.|Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, NY, USA. rmm257@gmail.com.
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Mitchell
authors.affiliation: Department of Bacteriology and TSE, Central Veterinary Institute part of Wageningen UR, Lelystad, The Netherlands. yschukken@cornell.edu.|GD Animal Health, Deventer, The Netherlands. yschukken@cornell.edu.
authors.forename: Ynte
authors.initials: Y
authors.lastname: Schukken
authors.affiliation: GD Animal Health, Deventer, The Netherlands. ad.koets@wur.nl.|Central Institute for Animal Disease Control, Lelystad, The Netherlands. ad.koets@wur.nl.
authors.forename: Ad
authors.initials: A
authors.lastname: Koets
authors.affiliation: GD Animal Health, Deventer, The Netherlands. m.weber@gdanimalhealth.com.
authors.forename: Maarten
authors.initials: M
authors.lastname: Weber
authors.affiliation: Central Institute for Animal Disease Control, Lelystad, The Netherlands. douwe.bakker@wur.nl.
authors.forename: Douwe
authors.initials: D
authors.lastname: Bakker
authors.affiliation: National Animal Diseases Center Ames, 2300 Dayton Avenue, Ames, IA, 50010, USA. judy.stabel@ars.usda.gov.
authors.forename: Judy
authors.initials: J
authors.lastname: Stabel
authors.affiliation: Department of Clinical Studies, University of Pennsylvania, Philadelphia, PA, 19104, USA. rhw@upenn.edu.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Whitlock
authors.affiliation: Gonda Brain Research Center and Department of Mathematics, Bar-Ilan University, Ramat Gan, Israel. louzouy@math.biu.ac.il.
authors.forename: Yoram
authors.initials: Y
authors.lastname: Louzoun
mesh_terms: D000818:Animals; D057138:Bacterial Shedding; D015415:Biomarkers / Q000378:metabolism; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000382:microbiology; D003612:Dairying; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005243:Feces / Q000382:microbiology; D008137:Longitudinal Studies; D016927:Mycobacterium avium subsp. paratuberculosis / Q000302:isolation & purification*; D009426:Netherlands / Q000453:epidemiology; D010283:Paratuberculosis / Q000453:epidemiology* / Q000382:microbiology; D014481:United States / Q000453:epidemiology
chemical_list: D015415:Biomarkers