Friday May 18 1:09
By Sara Kuzmarov
NEW YORK (Reuters Health) - Women who are infected with the Epstein-Barr virus in their teens may be at an increased risk of developing multiple sclerosis (MS), a new report suggests.
Overall, however, the risk of developing MS is extremely low and other factors such as genes may contribute to the development of the disease, Dr. Diane Griffen of Johns Hopkins University in Baltimore, Maryland, told Reuters Health. Griffen, who did not participate in the study, stressed that very few people who get mononucleosis, which can be caused by the Epstein-Barr virus, will go on to develop MS.
In the study, women who had mononucleosis were more than twice as likely to be diagnosed with MS compared with women who did not have the infectious disease, according to a report in the May issue of Epidemiology.
Among all women in the US, 3 to 4 per 1,000 will develop MS, the study's lead author Dr. Miguel A. Hernan noted in an interview with Reuters Health. This study, he said, suggests that among women with a history of mononucleosis, 6 to 8 per 1,000 will develop MS.
The findings are based on data from 301 women with MS and about 1,700 women without the disease. In addition to Epstein-Barr, infection with measles or mumps after age 15 was associated with an increased risk of MS.
While the results support other studies showing an association between infection with certain viruses and MS, it is not clear exactly how these infectious agents increase the risk.
Hernan suggested that a component of the Epstein-Barr virus might trigger an immune reaction that occurs in MS, an autoimmune disease in which the body attacks its own nerve cells.
``The theory is that there is some molecule in the virus that unintentionally mimics a protein in the body and triggers an immune response,'' said Hernan, a researcher at the Harvard School of Public Health in Boston, Massachusetts.
MS is a chronic, degenerative disorder in which the protective coating on nerve fibers, called myelin, becomes damaged. Its exact remains unknown. Symptoms include fatigue, muscle weakness, balance problems, and numbness and other sensory losses.
Studies have shown that women are more likely than men to be diagnosed with MS. Patients are usually diagnosed between the ages of 20 to 40 years.