Johne’s Disease remains a costly and persistent challenge facing Alberta’s dairy industry, causing millions of dollars in annual losses due to reduced milk production and removal of infected animals from the herd. Caused by Mycobacterium avium subspecies paratuberculosis (MAP), this chronic bacterial infection spreads primarily to calves via contaminated feed and water, with existing control methods showing limited success.
Dr. Jeroen De Buck at the University of Calgary is exploring a novel solution: mycobacteriophages, naturally occurring viruses with the potential to specifically kill MAP. These bacteriophages, or phages for short, could revolutionize how producers manage Johne’s disease.
In this RDAR-funded project, researchers studied phages from environmental samples collected across Alberta farms. In the lab, the team found that specific phages were effective at targeting and destroying MAP bacteria.
In a follow-up trial, a mixture of phages was given to calves by adding it to their milk replacer. Results were striking, calves receiving the phage treatment eliminated MAP shedding in feces and did not develop infection in their intestinal tissues. In contrast, untreated calves displayed persistent infection and continuous MAP shedding.
While a full economic analysis is ongoing, phages are relatively straightforward to produce at scale, which may help keep costs manageable. Their ability to selectively target MAP minimizes disruption to the calf’s commensal microbiota, and when used in optimized phage combinations, also reduces the risk of resistance development, supporting their potential for sustainable on-farm use.
This research could offer major benefits for Alberta’s dairy industry, as phage therapy may help reduce the spread of Johne’s disease, improve animal welfare, decrease economic losses, and boost farm profitability.
With ongoing support from RDAR and Alberta Milk, further research is focused on genetically engineering phages to eliminate resistance mechanisms, improve biocontainment, and better understand phage persistence in the intestinal environment. While work continues, the findings already represent a significant step forward, positioning Alberta’s dairy producers at the forefront of innovative disease management strategies.