Enzyme-linked immunosorbent assay for evaluation of antibody to canine distemper virus.

An enzyme-linked immunosorbent assay (ELISA) for canine immunoglobulin (Ig) G antibodies to canine distemper virus (CDV) was developed and its test results were compared with those of the serum-neutralization (SN) test. The sera of 273 random-source adult dogs were examined. The two tests had a high degree of correlation. Very few discrepancies occurred and most of these were at the lower limits of each test. When the sera were tested at 1:100 dilution, there was a 98% agreement between the ELISA and SN test. Titrated SN and IgG ELISA tests also were performed on sera from 77 dogs whose lifetime medical histories were known. The results showed excellent agreement between the tests. Only five of the 77 sera showed any discrepancies and these were at detection-threshold levels. To follow antibody development in two dogs experimentally infected with CDV, it was necessary to use an ELISA which detected both canine IgM and IgG. The ELISA detected CDV-specific IgM a week before the SN test results became positive. The IgM titers rose for 3 weeks and descended to lower levels about the 4th and the 5th weeks. The SN titers closely followed the IgM titers. The ELISA detected IgG antibody about the 5th and the 6th weeks of infection. Results of both the SN test and the IgG ELISA remained elevated through the 70th day of testing.