Author Institution: Food Animal Health Research Program, The Ohio State Universit

Sreevatsan, Srinand

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Johne’s disease (JD) is a chronic intestinal disease of ruminants, including domestic and wild species, caused by Mycobacterium avium subspecies paratuberculosis (MAP). It has been estimated that at least 40 percent of herds in the United States with more than 300 animals per herd are infected. JD has also been predicted to impose an economic burden of $1.5 billion annually to the U.S. agricultural industry. Furthermore, JD has been implicated as a possible etiological agent of Crohn’s disease in humans. Despite considerable research efforts, prevention and control strategies of JD remain problematic.MAP persistently infects and survives within host cells called macrophages. Currently, there are no reports on the behavior of diverse clinical isolates of M. paratuberculosis within a host/host cell (macrophage). Scientists believe that this critical piece of evidence is important to understanding the complex mechanisms underlying the virulence of this economically important animal pathogen.Comparative Pathogenomics of Epidemiologically  and Genetically Diverse Strains of Mycobacterium avium subspecies paratuberculosisSrinand Sreevatsan, Food Animal Health Research ProgramThe OARDC Research Enhancement Competitive Grants ProgramOhio Agricultural Research and Development CenterCollege of Food, Agricultural, and Environmental SciencesNumber 43■ Johne’s disease, a chronic intestinal disease of ruminants, imposes a $1.5 billion economic burden on  the U.S. agricultural industry annually.Comparative gene expression of clinical isolates of MAP in a bovine monocyte-derived macrophage environment was studied. Selective capture of transcribed sequences was employed to identify the genes expressed by a MAP strain (MAP6) isolated from a Crohn’s disease patient. cDNA libraries were created from macrophages exposed to MAP. Results suggest that the bovine and the human MAP isolates lead to anti-inflammatory and anti-invasive pathways in the macrophage environment whereas, in sheep, the MAP leads to a more pro-inflammatory pathway. Thus, the infecting strain genotype may play a role in polarizing the host immune responses and dictate the outcomes in this economically important disease.The data collected for this study enabled scientists to write a successful proposal to USDA for $350,000 to study genotype-specific host pathogen interactions. These studies will significantly increase our understanding of the early molecular events involved in the pathogenesis of JD, enabling scientists to design intervention strategies such as vaccines and early diagnostic tests.This research is supported in part by state of Ohio funds allocated to the Ohio Agricultural Research and Development Center of The Ohio State University.August 2007 FS43-07

Comparative Pathogenomics of Epidemiologically and Genetically Diverse Strains of Mycobacterium avium subspecies paratuberculosis

https://kb.osu.edu/bitstream/1811/49848/1/OARDC_SEEDS_No-43_Comparative_Pathogenomics.pdf

Comparative Pathogenomics of Epidemiologically and Genetically Diverse Strains of Mycobacterium avium subspecies paratuberculosis

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