Presence of Mycobacterium avium Subspecies paratuberculosis Monitored Over Varying Temporal and Spatial Scales in...

Area of Science:

• Environmental microbiology
• Water quality monitoring
• Veterinary epidemiology

Background:

• Mycobacterium avium subspecies paratuberculosis (Map) is the causative agent of Johne's disease in livestock.
• Understanding Map's environmental persistence and transmission routes is crucial for disease control.

Purpose of the Study:

• To monitor Map in the River Tywi catchment over a 10-year period.
• To investigate the environmental continuum of Map from infected animals to river systems.
• To identify potential transmission routes and inform monitoring strategies.

Main Methods:

• Quantitative PCR (qPCR) was used to detect and quantify Map DNA.
• Monitoring was conducted across various temporal and spatial scales within the River Tywi catchment.
• River foam samples were analyzed for the presence of Map.

Main Results:

• Map showed persistence over a 10-year period, correlating with Johne's disease levels in British herds.
• Map was consistently detected in river water at high concentrations (up to 10^8 cell equivalents L^-1).
• Natural river foams were identified as a novel reservoir for Map, suggesting aerosol-based spread.

Conclusions:

• Map is environmentally persistent in river systems, originating from infected livestock and transmitted via runoff.
• Small wastewater treatment plants did not significantly impact Map levels.
• Regular river monitoring, such as weekly or monthly sampling, can effectively capture Map dynamics.