Further evidence of a possible association between house dogs and multiple sclerosis.

The present study was undertaken because of the recent report of an association between familial multiple sclerosis (MS) and prior ownership of a small pet. Forty-five patients with sporadic MS were retrospectively compared with 45 closely matched controls and were found to have owned a significantly greater number of indoor dogs prior to the onset of MS. Importantly, the MS patients had also had more exposure to neurologically ill dogs in the five years before the onset of symptoms. These new data further support the hypothesis that house dogs may serve as an animal vector in MS.