Development of a Blocking ELISA for Screening Antibodies to Porcine Rubulavirus, La Piedad Michoacan Virus

A blocking enzyme-linked immunosorbent assay (ELISA) was developed to detect antibodies to porcine rubulavirus (La Piedad Michoacan Virus (LPMV)) in serum samples from pigs. The test, based on a monoclonal antibody against the LPMV hemagglutinin-neuraminidase glycoprotein, had a sensitivity of 99% and a specificity of 97%. The results of this test were in agreement with those obtained by an indirect ELISA and hemagglutination inhibition, indirect immunofluorescence, and virus neutralization tests. The blocking ELISA is considered the most suitable test for routine screening for antibodies against LPMV. The family Paramyxoviridae is classified into 4 gen- era: Paramyxovirus, Rubulavirus, Morbillivirus , and Pneumovirus. 13 These viruses have been identified as the causative agents of a variety of diseases in both humans and animals. Some of these viruses, such as Newcastle disease virus in chickens, 3 canine distemper virus in dogs, 1 and measles and mumps viruses in hu- mans, 5,15 can affect the central nervous system. The porcine rubulavirus was originally isolated from the brain of a piglet showing signs of a central nervous system disorder, pneumonia, and corneal opacity. 9 The disease was first observed in 1980 during an outbreak of encephalitis in piglets on farms around the town La Piedad, district of Michoacan, Mexico. Since the re- port of the initial outbreak of the disease, the La Pie- dad Michoacan virus (LPMV) has spread throughout Mexico and is now endemic in that country. 16 Because