New diagnostic approach may help detect Johne’s disease in cattle earlier

A preliminary study by MI:RNA Diagnostics and Scotland’s Rural College (SRUC) has found that microRNA profiling in combination with advanced predictive modeling and artificial intelligence (AI) may help diagnose Johne’s disease in cattle with greater accuracy. According to MI:RNA, a veterinary diagnostics company, the new diagnostic approach could change the way the disease is managed.¹

Paratuberculosis, also known as Johne’s disease, is an infectious, chronic disease that is often fatal and affects cattle and other ruminants, including sheep and goats. The disease, caused by a resistant species of the mycobacterium avium subspecies paratuberculosis (MAP) bacteria, causes granulomatous enteritis—a chronic form of inflammatory bowel disease—resulting in reduced nutrient absorption that leads to weight loss, diarrhea, and eventually death.^2,3

Endemic globally, including in the United States, Johne’s disease represents a high economic cost to the agricultural economy due to reduced milk production, late pregnancy, or failure during breeding season, early culling, and poor condition at culling.^2,3 In the US, the disease is believed to be more prevalent in beef cattle than commonly assumed due to a lack of recent survey data evaluating its current prevalence, according to a publication in Edis by the University of Florida’s Institute of Food and Agricultural Sciences Extension.³

USDA 2020 survey data shows that 7.9% of beef cattle herds in the US have one or more cows that are positive for Johne’s disease.³ Moreover, 92% of the US beef producer survey participants did not know about the disease or recognized the name but did not know much about it.³ Additionally, 2017 data from Johne’s Testing Center revealed that MAP was detected in 18% of the samples submitted from beef cattle herds.³

In the United Kingdom, Johne’s disease is especially prevalent, affecting up to 50% of herds. Each year, the disease costs an estimated 200 euros per cow and 10 million euros to the UK agricultural economy.¹

Photo: Savo Ilic/Adobe Stock

Currently, diagnostic tests for Johne’s disease pose limitations, with available diagnostic tests “exacerbate[ing] the difficulty of managing Johne’s disease, which often goes undiagnosed due to silent carriers of the disease,” according to MI:RNA.¹ However, the new diagnostic approach using microRNA developed by the diagnostics company and a team of scientists at SRUC may help the disease be identified earlier.

MicroRNAs are cellular RNA fragments that control the proteins that cells produce and regulate gene expression.¹ These biomarkers offer insight into what happens in cells as they are stable and easily detected in bodily fluids.¹ Research indicates that microRNA expression levels vary during bacterial infections, including early-stage MAP.¹

According to MI:RNA, diagnostic precision can be improved by applying advanced statistical and machine learning techniques, which enable rapid data analysis, detect patterns missed by traditional methods, and offer infection predictions.¹

In the preliminary study bySRUC and MI:RNA, microRNA expression was measured in samples from cattle infected with MAP and those not infected. With machine learning AI, the data was then analyzed and an optimal method if disease diagnosis was developed.¹

According to the study’s results, microRNA profiling, along with advanced predictive modeling, shows potential in serving as a diagnostic tool for Johne’s disease in cattle. However, because a small sample size was used for the preliminary study, future efforts will increase the sample size to further validate the results and ameliorate precision.¹

“Animal health is more important than ever, with Johne’s disease costing farmers tens of millions around the UK each year,” Eve Hanks, founder and CEO of MI:RNA Diagnostics, said in a company release.¹ “For MI:RNA, this is a key area of research and development. Biomarker science combined with our AI-powered modelling means that we can significantly improve animal health, reduce financial strain on farmers, while also reducing greenhouse gas output as a result. We believe [micro]RNAs can assist with progressing future diagnostic testing and understanding diseases more effectively.”

References

1. The silent killer: Breakthrough in pursuit of Johne’s Disease diagnoses. News release. MI:RNA Diagnostics. May 20, 2025.
2. Johne’s disease. US Department of Agriculture Animal and Plant Health Inspection Service. September 24, 2024. Accessed May 21, 2025. https://www.aphis.usda.gov/livestock-poultry-disease/cattle/johnes#:~:text=Johne's%20disease%20is%20endemic%20in,reduce%20the%20disease's%20national%20prevalence.
3. Stice B, Wiggins L, Thrift T, Bittar J. Johne’s Disease in Beef Cattle. EDIS. 2023;2023(6):VM256. doi:10.32473/edis-vm256-2023.