Elucidating Transmission Patterns of Endemic Mycobacterium avium subsp. paratuberculosis Using Molecular Epidemiology.

• Type of Material: Article
• Authors: Rebecca Mitchell, Emory University; Annabelle Beaver, Cornell University; Elena Knupfer, Cornell University; Abani K. Pradhan, University of Maryland; Terry Fyock, University of Pennsylvania; Robert H. Whitlock, University of Pennsylvania; Ynte H. Schukken, Cornell University
• Language: English
• Date: 2019-03-20
• Publisher: MDPI
• Publication Version: Final Published Version
• Copyright Statement: © 2019 by the authors.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.3390/vetsci6010032
• Title of Journal or Parent Work: Veterinary science in China
• ISSN: 1673-4696
• Volume: 6
• Issue: 1
• Start Page: 32
• Grant/Funding Information: RM has also received support from USDA NIFA Post-doctoral fellowship (AFRI-NIFA award 2011-67012-30725).; This work was supported in part by the USDA ARS (agreements 58-1265-3-155, 58-1265-3-156, 58-1265-3-158, 58-1265-4-020, and 58-1265-8-064) for the Regional Dairy Quality Management Alliance (RDQMA), the Johne’s Disease Integrated Program (JERDP; USDA contract 45105), and USDA-CSREES-NRI award 2007-35204-18391.
• Keywords: mutation rate; MLSSR typing; mycobacterial co-infections; within-host evolution; Mycobacterium avium subsp. paratuberculosis (MAP); vertical transmission
• Research Categories: Biology, Veterinary Science; Health Sciences, Epidemiology; Health Sciences, Nutrition

Abstract

Mycobacterial diseases are persistent and characterized by lengthy latent periods. Thus, epidemiological models require careful delineation of transmission routes. Understanding transmission routes will improve the quality and success of control programs. We aimed to study the infection dynamics of Mycobacterium avium subsp. paratuberculosis (MAP), the causal agent of ruminant Johne's disease, and to distinguish within-host mutation from individual transmission events in a longitudinally MAP-defined dairy herd in upstate New York. To this end, semi-annual fecal samples were obtained from a single dairy herd over the course of seven years, in addition to tissue samples from a selection of culled animals. All samples were cultured for MAP, and multi-locus short-sequence repeat (MLSSR) typing was used to determine MAP SSR types. We concluded from these precise MAP infection data that, when the tissue burden remains low, the majority of MAP infections are not detectable by routine fecal culture but will be identified when tissue culture is performed after slaughter. Additionally, we determined that in this herd vertical infection played only a minor role in MAP transmission. By means of extensive and precise longitudinal data from a single dairy herd, we have come to new insights regarding MAP co-infections and within-host evolution.