A variant of the direct immunofluorescence technique used in the routine diagnosis of PRRS syndrome

Abstract

Laboratory diagnosis of PRRS syndrome is based on virus detection, isolated strain characterization and antibody detection. Given the severity of the disease, rapid diagnostic methods are used to detect the nucleocapsid viral antigen present in the target organs (lymph nodes, lungs). From swine youth corpses from disease outbreaks, inguinal lymph nodes were taken, and from swine youth with characteristic respiratory symptoms, samples of oronasal fluid were taken. The nucleocapsid viral antigen was detected using the anti PRRSV monoclonal antibody kit labeled with fluorescein isothiocyanate (BIO 268). The smears made of lymph nodes and oronasal fluid to which they were identified, in the microscopic field, the described aspects were considered positive. Thus, 26 samples of lymph nodes (65%) and 9 oronasal fluid samples (45%) were positive, which were controlled to confirm PRRS virus presence by RT-PCR technique. All positive samples of lymph nodes and oronasal fluid positive to the IFD technique in the adapted working variant were confirmed as positive samples by the RT-PCR technique.