Duncan Harris

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Three liquid media that differ slightly in composition but not in the method of preparation were developed for the propagation of Treponema hyodysenteriae and Treponema innocens. The three media are unique in that all components are sterilized by autoclaving before use. These media supported better growth of T. hyodysenteriae than did previously used liquid(More)
OBJECTIVE To evaluate polymerase chain reaction (PCR) for detection of Lawsonia intracellularis DNA in feces and an indirect fluorescent antibody test (IFAT) for detecting serum IgG antibodies in pigs exposed to L intracellularis. ANIMALS 15 seven-week-old pigs and 42 three-week-old pigs. PROCEDURE During 3 experiments, 23 pigs were inoculated with a(More)
An enzyme-linked immunosorbent assay (ELISA) for Lawsonia intracellularis was developed and compared with a whole-cell antigen-based immunofluorescence antibody test (IFAT). The antigen-containing lipopolysaccharide (LPS) was derived from Percoll gradient purified cultures of L. intracellularis by using a modification of the Westphal hot phenol procedure.(More)
An alphavirus derived replicon particle (RP) vaccine expressing the cluster IV H3N2 swine influenza virus (SIV) hemagglutinin (HA) gene induced protective immunity against homologous influenza virus challenge. However, pigs with maternal antibody had no protective immunity against challenge after vaccination with RP vaccines expressing HA gene alone or in(More)
Gnotobiotic pigs were orally exposed to various anaerobes at 6 to 9 days of age and similarly inoculated with Treponema hyodysenteriae B204 3 to 6 days later. Watery diarrhea and fecal excretion of large quantities of mucus and some fibrin clots were observed 4 to 20 days after inoculation with B204 if other anaerobes were present. Colonic lesions(More)
Multiple, ligated loops of swine colon were used as an in vivo model in which to test enteropathogenicity of isolates of Treponema hyodysenteriae. Gross and microscopic lesions observed in 21 of 22 colonic loops in pigs killed 48 to 72 hours after inoculation with isolates known to be enteropathogenic were characteristic of swine dysentery. These lesions(More)
Isolates of Treponema hyodysenteriae from 25 geographically separated outbreaks of swine dysentery were tested for their ability to produce the disease. Clinical signs and lesions typical of acute swine dysentery were produced in 52 of 68 (75%) susceptible specific pathogen-free pigs that had been orally inoculated with pure cultures of 23 of 25(More)
Samples of faeces and of serum were collected from pigs of various ages on 21 farms. Faecal samples were cultured on trypticase soy agar containing 5 per cent citrated bovine blood and 400 micrograms per ml spectinomycin, incubated at 42 degrees C in Gaspak jars under an atmosphere of 80 per cent hydrogen: 20 per cent carbon dioxide. Antibody titres to(More)
Proliferative enteropathy (PE; ileitis) is a common intestinal disease affecting susceptible pigs raised under various management systems around the world. Major developments in the understanding of PE and its causative agent, Lawsonia intracellularis, have occurred that have led to advances in the detection of this disease and methods to control and(More)