Dogs, distemper, and multiple sclerosis in the United States.

Geographic distribution of multiple sclerosis (MS) was defined by case/control ratios for state of pre-illness residence for US white male veterans "service-connected" for MS. The Veterinary Medical Data Program of the National Cancer Institute receives diagnostic information from most of the university veterinary medical centers in the US (and Canada). The Center for Disease Control had carried out a 2-year surveillance program for human bites by animals. State distributions for MS were compared with those for the proportion of admissions for canine distemper (CD), the ratio of CD cases to the human population, and human bites by dogs per unit of population. There was no evidence that any of the CD risk indices was positively correlated with that for MS. These results suggest that CD, exposure to dogs, or dog bites are unlikely to be involved in the etiology of MS.