Rheumatoid arthritis, which causes painful swelling in the joints, is an auto-immune disorder—but doctors haven’t been sure what triggers it.
Researchers at the Mayo Clinic think it could be gut bacteria. They noted that rheumatoid arthritis sufferers have a microbial imbalance caused by unusual bacterial activity. From that, they were able to trace the bacteria back to gut microbes that were in short supply in healthy people, but seemed to be abundant in the arthritis sufferer.
People with high levels of the bacteria were more likely to develop rheumatoid arthritis, if they didn’t have it already, said the researchers.
The bacteria were countered with another bacterium, which reduced the frequency and severity of symptoms, the researchers discovered in tests on laboratory mice. The healthy bacterium, Prevotella histicola, could become a successful treatment, and might also prevent the disease in the first place.