In a recent study, those with multiple sclerosis were found to be more likely to harbor antibodies for a disease toxin normally found in sheep. Could this be the missing puzzle piece? Share on Pinterest Could a sheep disease offer clues about MS? Multiple sclerosis (MS) affects an estimated 2.3 million people worldwide. Although its exact prevalence in the United States is not known, the condition tends to be more common the farther from the equator that one travels. MS affects the central nervous system (CNS) and can cause a range of symptoms — often involving problems with movement, sensation, balance, and vision. Symptoms generally appear when an individual is in their 20s or 30s. Some can be managed, and, in some cases, progression of the disease can be slowed. However, there is still no cure.

Hunting for a cause MS is an autoimmune disease, in which the immune system attacks otherwise healthy tissue — in this case, the CNS. Why the immune system should turn on itself is still not understood. Despite decades of work, the exact cause of the disease is still shrouded in mystery, though both genetic and environmental factors are thought to be involved. Recently, a group of researchers at the University of Exeter in the United Kingdom looked for clues about MS’s origins in a surprising place: sheep. The first clues that sheep might provide some insight into MS came in 2013, when a team in the U.S. noticed that some people with MS had increased levels of antibodies to a toxin known as epsilon toxin (ETX). In other words, ETX had entered their bodies and triggered an immune response, there producing antibodies that were kept in reserve, ready to attack the toxin if it returned in the future. This toxin is produced by the bacterium Clostridium perfringens, found in the guts of livestock — most commonly in sheep. ETX crosses the gut wall and builds up in the kidneys and brain. And, once in the brain, it destroys both the myelin that coats nerves and the cells that produce myelin. In sheep, this type of ETX poisoning is called enterotoxemia, or pulpy kidney disease. Myelin is a waxy layer that coats many nerve cells. It is essential for carrying signals quickly and efficiently. In MS, myelin and the cells that produce it are destroyed by the immune system. This striking similarity between enterotoxemia and MS makes any potential relationship worth investigating further.