By intensive study of environmental conditions during the final stages in an active cluster area, an attempt is made to crack the enigmatic deadlock concerning the origin and etiological cause of Multiple Sclerosis (MS). Previous investigations of other cluster areas have emphasized the probability that the outbreaks of MS were most likely caused by an unknown exogenous environmental agent, but unfortunately, the studies were conducted several years after the epidemics had occurred, making it virtually impossible to observe changing environmental conditions. This study attempts to overcome such defects, and in the process identifies not only the probable exogenous viral agent(s), but the here-to-fore unknown avian vectors as well.