- A common bacteria called MAP present in milk and beef is linked to rheumatoid arthritis
- About 1.3 million US adults were found to have rheumatoid arthritis
- MAP can spread to humans through consumption of infected milk, beef and produce fertilized by cow manure
A common strain of bacteria found in milk and beef can increase the risk of developing rheumatoid arthritis, reveals a new study.
Rheumatoid arthritis Linked to MAP
Rheumatoid arthritis (RA) was found to be associated with Mycobacterium avium subspecies paratuberculosis (MAP), which is present in about half the cows in the US, reveals a research team of University of Central Florida College of Medicine.
MAP is a bacteria that can be spread to humans through the consumption of infected milk, beef and produce fertilized by cow manure.
The study was a collaboration between Saleh Naser, UCF infectious disease specialist, Dr. Shazia Bég, a rheumatologist at UCF's physician practice, and Robert Sharp, a biomedical sciences doctoral candidate at the medical school. This study was funded in part by a $500,000 grant from the Florida Legislative.
Link between MAP and Crohn's Disease
In the previous study, a link between MAP and Crohn's disease was discovered by Naser. The study was the first ever phase III-FDA approved a clinical trial in treating Crohn's patients with antibiotics.
The same genetic predispositions are seen in both Crohn's and rheumatoid arthritis. Also, the same type of immunosuppressive drugs is used in treating them. These similarities have led the research team to investigate whether the MAP has a link with RA.
"Here you have two inflammatory diseases, one affects the intestine, and the other affects the joints, and both share the same genetic defect and treated with the same drugs. Do they have a common trigger? That was the question we raised and set out to investigate," said Naser.
Bég recruited about 100 of her patients for this study who volunteered clinical samples for testing.
Nearly 78 percent of the patients with RA had a mutation in the PTPN2/22 gene. The same genetic variation was also found in Crohn's patients, and 40 percent of these patients were tested positive for the MAP.
Naser said that individuals who are born with this genetic mutation and exposed to MAP later in life either by consuming contaminated milk or meat from infected cattle are at a higher risk of developing RA.
What is Rheumatoid arthritis?
Rheumatoid arthritis (RA) is an autoimmune and inflammatory disease that causes the immune system to attack the bones, joints, muscles, and organs.
Individuals usually suffer from pain and deformities mostly in their hands and feet. RA can occur at any age. However, the onset is between 40 and 60 years old and is three times more prevalent in women.
In the U.S, about 1.3 million adults were found to have rheumatoid arthritis.
Some RA patients suffer from Crohn's disease and vice versa. However, the research team suggested that further investigation needs to be made on the incidence of both the conditions in the same patients.
"We don't know the cause of rheumatoid arthritis, so we're excited that we have found this association. But there is still a long way to go. We need to find out why the MAP is more predominant in these patients - whether it's present because they have RA, or whether it caused RA in these patients. If we find that out, then we can target treatment toward the MAP bacteria," said Bég.
Need for Further Study
The research team is further investigating to confirm the findings and is also planning to study patients from different geographical and ethnic backgrounds.
Understanding the role of MAP in RA patients can help treat the disease more effectively. A combination treatment that targets both inflammation and bacterial infection may be developed, said Naser.