Abstract: The present invention is a live vaccine from a culture of cells of Haemophilus parasuis exhibiting attenuated pathogenicity and capable of triggering a protective immune response when administered to pigs. The cell culture was modified from a pathogenic parent strain by MNNG mutagenesis and was selected by complete dependence on streptomycin for growth. Several SNPs have been identified as associated with specific proteins that are associated with virulence as seen in the literature in H. parasuis or related bacterial species.

Abstract: The present invention is a culture of cells of Haemophilus parasuis exhibiting attenuated pathogenicity and capable of triggering a protective immune response when administered to pigs as a live vaccine. The present invention is also a method of preparing the cell culture, a method of preparing a vaccine from the cell culture, and a live vaccine based on the cell culture. The cell culture was modified from a pathogenic parent strain by MNNG mutagenesis and was selected by complete dependence on streptomycin for growth.

Abstract: A protein (xylanase) has been identified that produces a strong immune response in pigs when added to a vaccine. The protein is added to vaccines at a particular concentration. The protein is delivered to the animal as part of the vaccine and elicits an immune reaction (antibodies are generated by the animal against the compliance marker protein). The antibodies are then detected in sera samples by a diagnostic test, enzyme-linked immunosorbent assay (ELISA). In the ELISA compliance marker assay, the marker protein (antigen) in coated onto polystyrene plates and is used to detect antibodies against the marker in sera samples. This combination of marker protein added to vaccines and the ELISA to detect antibodies raised against the marker protein can be used to determine whether a particular animal(s) has been vaccinated. The selected protein is commercially-available, identified as Generally Recognized as Safe by the FDA, and does not cause adverse reactions in animals.