Multiple sclerosis can result in permanent disability and severe weakness. In the large majority of cases, there are no risks to others. There may be a risk to others if, for example, a drunk person drives a car. In some cases, an infection is the cause of ataxia. The underlying infection may be contagious.
Treatment is directed at the underlying cause.
For example, drugs can help reduce ataxia if Parkinson's disease is the cause. Antibiotics may be needed for an infection. Surgery may remove a brain tumor. If a stroke is the cause, the only treatment may be physical therapy to improve function as much as possible. All medications have possible side effects.