Symptoms vary because the location and extent of each attack varies. Usually episodes that last days, weeks, or months - alternate with times of reduced or no symptoms (remission). Recurrence (relapse) is common although non-stop progression without periods of remission may also occur.
Researchers are not sure what triggers an attack. Patients with MS typically have a higher number of immune cells than a healthy person, which suggests that an immune response might play a role. The most common theories point to a virus or genetic defect, or a combination of both. There also appears to be a genetic link to the disease.
MS is more likely to occur in northern Europe, the northern United States, southern Australia, and New Zealand than in other areas. Geographic studies indicate there may be an environmental factor involved.
People with a family history of MS and those who live in a geographical area with a higher incidence rate for MS have a higher risk of the disease.
levitra kaufen
levitra acquistare
comprare levitra
Mar 15