Tests for the PRRS virus itself also exist. These include RT-PCR and virus isolation. For virus isolation, buffy coat, serum, lung, lymph nodes, spleen and tonsils are the specimens of choice. The virus is incubated with swine pulmonary alveolar macrophages, and cytopathic effect are seen in around four days. RT-PCR can be performed on whole blood, buffy coat and clarified homogenates of the tissues appropriate for virus isolation. The test is particularly useful for examination of mummified or aborted litters. Immunohistochemistry is also possible, and nucleic acid sequencing of the 5' end of the virus has recently become commercially available. This is useful for comparing isolates recovered from different sites in order to facilitate epidemiological investigations. | Tests for the PRRS virus itself also exist. These include RT-PCR and virus isolation. For virus isolation, buffy coat, serum, lung, lymph nodes, spleen and tonsils are the specimens of choice. The virus is incubated with swine pulmonary alveolar macrophages, and cytopathic effect are seen in around four days. RT-PCR can be performed on whole blood, buffy coat and clarified homogenates of the tissues appropriate for virus isolation. The test is particularly useful for examination of mummified or aborted litters. Immunohistochemistry is also possible, and nucleic acid sequencing of the 5' end of the virus has recently become commercially available. This is useful for comparing isolates recovered from different sites in order to facilitate epidemiological investigations. |