Mycobacterium avium subspecies paratuberculosis seroconversion in dairy cattle and its association with raised somatic cell count

Benjamin M Barber,Nick Bell,Steven Van Winden

doi:10.1136/vr.104923

Abstract

This retrospective case–control study investigates the relationship between seroconversion to Mycobacterium avium subspecies paratuberculosis (MAP) and raised somatic cell count (SCC). The study consists of 112 case cows from three...

Highlights

Paratuberculosis, known as Johne’s disease, is a chronic, progressive, enteric disease caused by Mycobacterium avium paratuberculosis (MAP), which primarily affects ruminants
The results show that cases cows tended to have increased Somatic cell counts (SCC) around the time that seroconversion occurred compared to matched control cows; both at the point the antibody test first became seropositive (Time0) as well as the milk recording approximately one month earlier
The results suggest that cows that are progressing to MAP seropositive status have concurrent elevated SCC as well as during the time period leading up to this point, compared to matched control cows

Summary

Introduction

Paratuberculosis, known as Johne’s disease, is a chronic, progressive, enteric disease caused by Mycobacterium avium paratuberculosis (MAP), which primarily affects ruminants.In addition to the impact of clinical Johne’s disease on cows, there is an interest in the disease due to the reported association between MAP and the enteric condition Crohn’s disease in humans[1], which has driven efforts to improve disease detection and its subsequent control.When the animal is exposed to the pathogen most studies agree that the main portal of entry is the ileum where the MAP organisms are taken up by M cells within the Peyer’s patches[2,3]. Paratuberculosis, known as Johne’s disease, is a chronic, progressive, enteric disease caused by Mycobacterium avium paratuberculosis (MAP), which primarily affects ruminants. In addition to the impact of clinical Johne’s disease on cows, there is an interest in the disease due to the reported association between MAP and the enteric condition Crohn’s disease in humans[1], which has driven efforts to improve disease detection and its subsequent control. When the animal is exposed to the pathogen most studies agree that the main portal of entry is the ileum where the MAP organisms are taken up by M cells within the Peyer’s patches[2,3]. As the disease progresses though this granulomatous response becomes more severe and diffuse, eventually becoming the cause of the clinical signs[6]

Methods

Results

Conclusion