Enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to reticuloendotheliosis virus (REV) at single serum dilution was standardized. REV HI, one of the Korean field isolates, was inoculated into chicken embryo fibroblast (CEF) cells and was harvested from the culture fluids and cells after 10 to 12 days. Viruses were purified by centrifugation at the 107,000×g for 12 hours on 20, 30, 45% (W/V) sucrose gradient. Virus specific fraction was collected and used as ELISA antigen. To standardize ELISA, the optimal concentration of coating antigen (1 ㎍/well) and conjugate (1/1000) was determined by corrected OD (OD value of positive serum-OD value of negative serum) and P/N ratio (OD value of positive serum/OD value of negative serum).

African swine fever (ASF) is an infectious disease of domestic and wild pigs for which there is no vaccine in the world. A proper surveillance of viral activity and a timely response to ASF outbreaks depend upon the rapid diagnosis of ASF viral infection. Internationally prescribed enzyme-linked immunosorbent assay (ELISA) is a fast, sensitive test routinely used in the diagnosis of the ASF. However, inactivated whole ASF virus antigen used in this test is a tedious to prepare and has a risk of outside exposure of infectious virus by laboratory accident during the preparation.

Serum samples of 1,175 pigs from 148 Korean swine farms not using Mycoplasma hyopneumoniae (M. hyo) vaccines were collected for seroepidemiological study of M. hyo infection by indirect ELISA method. Informations of each farm were provided about province where the farm was located and season when blood samples were collected. Then, the selected farms were divided into farm units which had 5 serum samples according to production stages : sow, suckling piglet (less than 30 days old), nursery pig (30-70 days old), and growing pig (greater than 70 days old).