Contact with dogs, canine distemper virus, and multiple sclerosis

Abstract

A case-control study of 28 multiple sclerosis (MS) patients and 23 other neurological disease (OND) controls matched on age, sex, and clinic location, was conducted to evaluate the possible effects of selected viral infections on the development of multiple sclerosis. All study subjects were members of the Scott and White Health Plan and residents of Belton, Bryan, College Station, or Temple, Texas. Participation entailed completing a 30-minute questionnaire and donating approximately 16 ml of venous blood. The questionnaire assessed exposure to dogs and other animals that can become infected with CDV. The questionnaire also obtained demographic information, residential, occupational, reproductive, and medical history, family history of disease, and multiple sclerosis data. Serum antibody titers to MV and CDV were measured using enzyme-linked immunosorbent assays (ELISA). Associations with serum antibodies to measles virus (MV) and canine distemper virus (CDV) were evaluated, while attempting to minimize the possibility of cross-reactivity. Two peptides were synthesized for each virus, using deduced amino acid sequences from segments of the hemagglutinin protein. The peptides were selected based on sequence heterogeneity between the two viruses and hydrophilicity. Elevated odds ratios were observed for several categories of self-reported exposures to dogs, however, 95% confidence intervals were wide, and included 1.0 in all instances. Mean absorbable values from ELISA did not differ significantly between cases and controls for any of the four peptides (t-test, p >0.05), nor did odds ratios show any significant associations between MS prevalence and serum absorbable values. Peptides that were previously reported as being specific to CDV exhibited highly correlated absorbable values with corresponding measles virus sequences (correlation coefficient >.95). Negative control antisera (rabbit anti-measles) for the distemper-origin peptides had higher absorbance values than the corresponding positive control antisera (dog anti-distemper). We were unable to reproduce work by other investigators showing that the two CDV peptides minimized the possibility of measuring cross-reactive serum MV antibody instead of CDV antibody.