Detection of Cattle Exposed to Foot-and Mouth Disease Virus by Means of an Indirect ELISA Test, Using Bioengineered Nonstructural Polyprotein 3ABC

MALIRAT, V; NEITZERT, E; BERGMANN, I., E; MARADEI, E; BECK, E.

VETERINARY QUARTERLY

Año: 1998 vol. 20 p. 24 - 26

0165-2176

An indirect enzyme-liked immunososrbent assay (I-ELISA) capable of detecting foot-and-mouth disease virus (FMDV)-specific antibodies in sera from animals with previous viral exposure was developed, as an alternative tool to the enzyme-linked immunoelectrotransfer blot (EITB) test previously described. Out of the 5 recombinant DNA-derived FMD nonstructural viral antigens used in the EITB assay, 3 ABC was selected as a serologic probe for the I-ELISA. High sensitivity for detection of acute as well as of subclinical infection, even at late stages of the persistent status, was indicted by the results for sera from naive animals following experimental infection, or following exposure to the virus under natural conditions. The ability of the test to identify FMDV persistently infected animals subjected to systematic vaccination was also demostrated. High specificity was revealed by evaluating sera from cattle in FMD-free regions without vaccination, including samples from cattle infected with a variety of bovine viruses. Analysis of ser from animals in FMD-free areas under regular vaccination campains, including cattle with multipe immunization cycles showed that, ocasionally, antibodies against 3ABC are elicited. The data persented herein indicate that, in agreement with results obtained with the EITB test, the I-ELISA detected FMDV-specific antibodies, also at late stages of the persitent infection, maintaining nonspecific reactions at low levels, even in regions under systematic vaccination. Use of the I-ELISA is suitable as a sensitive, safe, rapid, reproducible and economic test of the detection of previous virus exposure. A combination of screening by the I-ELISA together with confirmation of suspect serum samples by the more specific EITB assay is proposed for large scale epidemiological surveillance.