Master of Science / Department of Diagnostic Medicine and Pathobiology / Raymond R. R. Rowland / Three economically important swine diseases: Porcine Reproductive and Respiratory Syndrome (PRRS), Porcine Circovirus Associated Disease (PCVAD) and Swine influenza cost the US swine industry more than a billion dollars each year. This study developed a fluorescent microsphere immunoassay (FMIA) to simultaneously detect antibodies to the causative pathogens: PRRSV, porcine circovirus (PCV2) and swine influenza virus (SIV). The results showed that the multiplex assay possessed the predicted specificities. In the case of PRRSV NA, the assay displayed higher sensitivity when compared to a commercially available ELISA. The assay was employed to measure both IgG and IgM responses. The FMIA was found to possess several advantages over standard ELISA which include reduced sample volume, time and cost and provides a new tool for veterinary diagnostics. The FMIA was applied for swine disease surveillance in Hawaiian and Texan feral swine populations. The antibodies against PCV2 showed the highest prevalence among these three pathogens in both Hawaii and Texas. Hence we consider PCV2 as the most prevalent pathogen in Hawaiian and Texan feral pigs and this pathogen poses the greatest threat to commercial pigs. SIV seroprevelance increased from 2007 to 2010 in Hawaii State, suggesting an increasing risk for commercial pigs. Moreover, yearly surveillance in Texas State shows growth in seropositive response to all pathogens, particularly PCV2. The development of FMIA for detection of antibodies to multiple swine pathogens in serum samples offers an important alternative for swine disease surveillance in commercial and feral herds.

Haemophilus parasuis was grown in cystine-supplemented tryptone-yeast extract medium (TYE) sparged with CO$ sb2$-containing gas mixtures. The organism was found to metabolize glucose via acetate- and succinate-producing pathways and a complete tricarboxylic acid cycle was absent. As compared with the oxygen-sufficient organism, oxygen-restricted H. parasuis synthesized higher amounts of high and low potential cytochromes c, exhibited higher activities of the enzymes of the succinate-producing pathway and excreted less acetate and more formate and succinate. The low potential cytochromes c were reduced by NADH and oxidized by fumarate and were situated on both sides of the HOQNO inhibition site of the low potential portion of the electron transport chain, but did not seem strictly required for the NADH:fumarate oxidoreductase activity. It is suggested that the low potential cytochromes c might act as an electron buffer permitting the regeneration of NAD under conditions of scarcity of the final electron acceptor.

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