Pathogenesis

PATHOGENESIS
  • The organism is shed in the faeces, milk and semen of infected animals.
  • They remain viable in the environment for up to one year under suitable conditions.
  • Calves under one month of age are highly susceptible and they develop clinical disease than animals infected later in life.
  • Infection is acquired mainly through ingestion.
  • The organism is an intra cellular pathogen and cell mediated reactions are mainly responsible for the enteric lesion.
  • Ingested mycobacteria, engulfed by macrophages in which they survive and replicate, are found initially in Peyer’s patches.
  • As the disease progresses, an immune mediated granulomatous reaction develops, with marked lymphocyte and macrophage accumulation in the lamina propria and submucosa.
  • The resulting enteropathy leads to loss of plasma proteins and malabsorption of nutrients and water.
Last modified: Monday, 4 June 2012, 5:03 AM