Improvement of a serodiagnostic strategy for foot-and-mouth disease virus surveillance in cattle under systematic vaccination: a combined system of an indirect ELISA-3ABC with an enzyme-linked immunoelectrotransfer blot assay

Abstract

Foot-and-mouth disease (FMD) recombinant non-capsideal viral antigens 3A, 3B, 2C, 3D and 3ABC were assessed individually in an indirect enzyme-linked immunosorbent assay (I-ELISA) for their ability to screen for persistent infection-specific antibodies in cattle, regardless of vaccination condition. Results of sequential serum samples from non-vaccinated animals with experimentally induced persistent infection, and their correlation with virus isolation, indicated that the polypeptides 3A, 3B and 3ABC showed the most adequate characteristics for further field studies. Reliable performance of the I-ELISA with the selected antigen 3ABC was indicated by the distinct patterns observed for the frequency distribution values of naive and true positive samples. For regularly vaccinated livestock, a clear negative profile was proved in samples from regions without recent history of FMD. In contrast, at 90 and 900 days post-outbreak, coexistence of a positive and a negative population was established. These findings indicated that, irrespective of vaccination, the test allowed a classification of the herd-disease status. A high degree of agreement was observed between I-ELISA-3ABC and EITB results for clearly reactive and non-reactive sera. For samples with reactivity values close to that of the cut-off, the EITB profiles upheld the definition of the infection condition. On this basis, screening by I-ELISA-3ABC, together with confirmation of suspect or positive samples by EITB is proposed as an adequate and accurate approach for large-scale epidemiological surveillance.

Epidemic Characteristics of Foot and Mouth Disease on the Buffaloes and Cows in Lang Son Province, Vietnam

“…The result also shows that there is a relation between the number of buffaloes and cows carrying the virus and the number of buffaloes and cows suffered from FMD from 2011 to 2015. This result was similar to that of [7,9].…”

“…If other buffaloes, cows or other sensitive cattles such as pigs and goats are not vaccinated, they could easily develop the disease. This result corresponds to that of [7,9]. Table 9, and 10.…”

Comparison of Two 3ABC Enzyme-Linked Immunosorbent Assays for Diagnosis of Multiple-Serotype Foot-and-Mouth Disease in a Cattle Population in an Area of Endemicity

“…Inactivated vaccines are purified to remove cellular proteins and NSPs, and therefore only animals that have been infected with live virus should develop antibodies to these proteins (2,4,35). Currently, the polyproteins 3ABC and 3AB appear to be most promising as diagnostic antigens (6,15,30,37,41). They have been expressed as fusion proteins in Escherichia coli (30) and baculovirus vectors in insect cells (34,41) used in a variety of assays, including agar gel immunodiffusion (33), latex agglutination (42), immunoelectrotransfer blot analysis (3), and direct and blocking enzyme-linked immunosorbent assays (ELISAs) (30,39).…”

Differentiation of Foot-and-Mouth Disease Virus-Infected from Vaccinated Pigs by Enzyme-Linked Immunosorbent Assay Using Nonstructural Protein 3AB as the Antigen and Application to an Eradication Program

“…The antigens used were bioengineered proteins expressed in Escherichia coli (5,7,11,13,14) or baculovirus (17,18) or obtained from chemically synthesized peptides (15). The nonstructural protein 2C has also been reported to be useful for this purpose (9,10,12).…”