Published in Scientific Works. Series C. Veterinary Medicine, Vol. LXIII, Issue 2
Written by Larion FLUERAŞU, Virgilia POPA, Marius IOVĂNESCU, Viorel HERMAN, Nicolae CĂTANA
Porcine reproductive and respiratory syndrome (PRRS) is an infectious disease spread in intensive growth with endemic evolution and with economic significance. In Romania the disease was for the first time diagnosed in 1998 and nowadays the disease is prevalent in many farms of pigs. For detection of viral antigens were sampled lymph nodes with pathological lesions macroscopic characteristic of the PRRS, from cadavers of piglets from farms where the disease evolves, and from pigs with clinical evolution of the disease was taken oro-nasal fluid. Viral nucleocapsid antigen was detected using kit - Anti PRRSV monoclonal antibody labelled with fluorescein isothiocyanate -BIO 268. The cytoplasm of cells, infected with PRRS virus, had a brilliant greenish yellow appearance due to the presence of the viral nucleocapsid antigens coupled with monoclonal antibodies labeled with fluorescein. Epithelial cells were rare, smaller, and fluorescent appearance of the cytoplasm was very evident. In case of the oro-nasal fluid smears, in the microscopic field were highlighted cells agglomerations with highly fluorescent cytoplasm. 19/30 (63.33%) of the examined samples (lymph nodes and oro-nasal fluid) were positive, respectively, 12/30 (40%) of the lymph nodes and 7/30 (23.33%) of oro-nasal fluid. Samples of lymph nodes and oro-nasal fluid were examined also through RT-PCR in order to create a correlation between the results provided by direct immunofluorescence (DIF) and RT-PCR, regarded as the reference method. The results confirm that the DIF can be adapted but more research is required to establish the sensitivity and specificity of this method.
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