Use of oral fluids to detect anti Lawsonia intracellularis antibodies in experimentally infected pigs

Abstract

Several pathogens and antibodies derived from serum or produced in tissues associated with the oral cavity are present in the oral fluid (OF). Considering the applicability of this alternative sample, recent studies in veterinary medicine have tested OF as a replacement for serum in diagnostic assays. The aim of this study was to standardize the immunoperoxidase monolayer assay (IPMA) to detect anti-Lawsonia intracellularis immunoglobulin A (IgA) and immunoglobulin G (IgG) in OF samples from experimentally infected pigs. Sixty-two pigs were divided into two groups: control (T1, n=30) and inoculated with L. intracellularis (T2, n=32). Blood, OF and fecal samples were collected at 0, 7, 14, 21, 28 and 42 days post-inoculation (dpi). Some adaptations of the standard technique for serum were made to IPMA for the detection of IgA and IgG in OF. The IPMA showed high specificity and sensitivity for serum samples and high specificity and moderate sensitivity for the detection of IgA and IgG in OF. There was high agreement between the results of serum IgG and OF IgA and IgG. Based on our results, oral fluid samples may be used for the evaluation and determination of anti-L. intracellularis antibodies in pigs, but not for individual diagnosis of swine proliferative enteropathy.

Seroprevalence of Lawsonia intracellularis antibody among swine herds in Thailand, December 2021-March 2022

“…IFN-γ was detected in infected pigs as early as 10 days after infection and peaked at 20 days; as a result, it could be a viable strategy for developing an early diagnosis in pigs (Riber et al, 2015). Specific antibodies were detected in the serum, intestinal mucosa, feces, and oral fluid in relation to humoral immunity (Gabardo et al, 2021). A previous study by detected the highest titers of antigen-specific immunoglobulin (Ig)A in intestines between 15 and 29 dpi.…”