Delbert Linn Harris

Treponema innocens, a New Species of Intestinal Bacteria, and Emended Description of the Type Strain of Treponema hyodysenteriae Harris et al.

Twelve treponemes with serpentine morphology were isolated from pigs and dogs and were compared with strain B78, the type strain of Treponema hyodysenteriae Harris et al. Nine of the 12 were isolated from cases of swine dysentery, and these were similar in characteristics to strain B78. The three other isolates were not enteropathogenic for swine and could be differentiated from the aforementioned nine isolates on the basis of enteropathogenicity, hemolytic pattern, deoxyribonucleic acid homology, fructose fermentation, and indole production. The morphological and metabolic characters of the 12 isolates and an emended description of strain B78, the type strain of T. hyodysenteriae, are presented in this report. Based on these data, the nonpathogenic types are regarded as belonging to a new species, Treponema innocens. The type strain of T. innocens is strain B256 (=ATCC 29796).

Alphavirus replicon particle vaccines developed for use in humans induce high levels of antibodies to influenza virus hemagglutinin in swine: Proof of concept

A propagation-defective, single-cycle, alphavirus replicon particle (RP) system was used to produce two vaccines against human influenza virus A/Wyoming/03/2003 (H3N2). One vaccine was prepared from Venezeulan equine encephalitis virus (VEEV) strain 3014 and the other from VEEV strain TC-83. Both vaccines induced high antibody titers to the influenza hemagglutinin (HA) protein and illustrated the potential of using alphavirus RP influenza vaccines in swine.

Use of Pulsed-Field Gel Electrophoresis of Conserved XbaI Fragments for Identification of Swine Salmonella Serotypes

ABSTRACT Swine Salmonella isolates (n = 674) from various locations throughout the United States and Canada were analyzed via pulsed-field gel electrophoresis (PFGE) with XbaI. PFGE subtypes were analyzed by cluster analysis and compared to conventional serotyping results. The analysis showed a correlation of serotype to PFGE subtype. In addition, conserved fragments were identified within the restriction patterns that were unique to each serotype. PFGE using XbaI restriction provided a possible alternative method for screening and identifying swine Salmonella serotypes.

Nucleic-acid based antivirals: Augmenting RNA interference to ‘vaccinate’ Litopenaeus vannamei

The Pacific white shrimp, Litopenaeus vannamei (Penaeidae: Litopenaeus) has emerged as the dominant farmed shrimp species globally in tropical countries. Rearing animals at high density in semi-intensive or intensive culture systems, and translocating animals across the globe, have created optimum conditions for devastating epizootics. Of the various pathogens that impact shrimp culture, viruses are arguably the most important infectious disease agents that exact devastating economic losses to the industry. Augmenting the RNA interference (RNAi) capacity of shrimp is a promising, emerging solution to prevent disease caused by a variety of highly pathogenic shrimp viruses. Indeed RNAi functions as a primary mechanism of antiviral RNA in arthropods, as was revealed initially in studies of mosquito-virus interactions. Double-stranded RNA (dsRNA) or small interfering RNA (siRNA) can be used as RNAi triggers in vivo in L. vannamei to reduce the pathology associated with virus infection. We explored the efficacy of those triggers as a function of the target gene in the virus genome and show that efficacy is virus-specific and cannot be predicted based on the target gene function or transcript level in an infected cell. Further, we show that carefully designed RNAi triggers provide an immune stimulus that results in specific, long-term protection and therefore suggest that these dsRNA antivirals can function as vaccines in controlling disease.