Giardia and Cryptosporidium are intestinal protozoan parasites that infect a wide range of host species, including humans. DNA sequencing of Giardia and Cryptosporidium isolates from human and animal sources has identified numerous species and genotypes, and has demonstrated that a number of Giardia and Cryptosporidium genotypes are shared between animals and humans. Therefore, livestock may act as a source of contamination of the food and water supply. The goal of this study was to optimize methods for the detection and molecular characterization of Giardia and Cryptosporidium. Achieving this objective involved the incorporation of immunomagnetic separation, as well as the evaluation of different methods, including microscopy, flow cytometry and polymerase chain reaction. A number of faecal samples from adult cattle and calves were collected from farms in Ontario and Prince Edward Island (PEI). Following DNA extractions from stool samples, a nested-PCR was used for Giardia to amplify a fragment of the 18S rRNA gene generating a 292-bp product. Nested-PCR protocol was also used for Cryptosporidium to amplify fragments of the heat-shock protein 70 (HSP-70) gene (ca. 325 bp). For Giardia, of 143 cattle samples analyzed by PCR, 32 (22.4 %) were positive. When IMS was incorporated into the methodology, 64 out of 143 (44.8 %) samples analyzed were positive for Giardia. For Cryptosporidum, out of 143 cattle faecal samples analyzed by the PCR method using the HSP-70 gene, 58 were positive (40.6 %), while using IMS, plus PCR, 60 samples were positive (42 %). Results from this study indicated that incorporation of IMS significantly improve the sensitivity of PCR for the detection of both Giardia (p<0.01) and Cryptosporidium (p=0.02). Among the other genes that were targeted, including the beta-giardin gene and glutamate dehydrogenase (GDH) for Giardia, and the Cryptosporidium oocyst wall protein (COWP) and 18S rRNA for Cryptosporidium, the 18S rRNA for Giardia , and HSP-70 for Cryptosporidium were found to be the "best genes". When different methods, including microscopy, flow cytometry and PCR-IMS were compared, the PCR method showed the highest sensitivity in detecting both parasites. Genotyping done by DNA sequencing showed that there was a high prevalence of zoonotic genotypes (Assemblage A for Giardia , and C. parvum bovine genotype for Cryptosporidium ) among the samples from both PEI and Ontario. In addition, a temporal study was done on calf samples from Ontario and showed that over time there was a decrease in Cryptosporidium infections, concomitant with an increase in Giardia infections.

Thesis (Ph.D.)--Indiana University, Dept. of Psychological Brain Sciences, 2009. / Title from PDF t.p. (viewed on Feb. 10, 2010). Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3770. Adviser: William Timberlake.

These studies were begun during the summer of 1994, W2 years after the recognition of Taura Syndrome (TS), a lethal disease of farm-raised Penaeus vannamei in Ecuador of then unknown etiology. Utilizing specific pathogen free (SPF) P. vannamei test shrimp, the combined results of four initial TS bioassays suggested that the disease had an infectious instead of a toxic etiology as originally reported. The hypothesis that TS was virus-caused prompted the application of a shrimp parvovirus (IHHNV) purification protocol, which resulted in the discovery of Taura Syndrome virus (TSV), a previously unrecognized virus that was isolated from TS diseased shrimp tissues. Three serial infectivity studies were performed in which purified cell-free extracts of TSV were injected into SPF P. vannamei test shrimp and the criteria of Rivers' postulates were fulfilled, establishing that TS has a viral etiology. In situ hybridization assays for the detection of TSV resulted in frequent false negative gene probe results. This problem was due to fixative-induced acid hydrolysis of the TSV RNA genome resulting from tissue fixation with Davidson's solution (pH 3.5-4). Development and use of a neutral fixative, R-F (RNA-Friendly) fixative, was shown to prevent this problem. The pathogenesis of TSV lesions was analyzed in experimentally infected, time course sampled SPF P. vannamei. The TSV disease cycle was found to consist of three clinically and histologically distinct overlapping phases; an W7 d acute phase, an W5 d transition phase and a long term cyclic chronic phase of at least 8 months duration. TSV susceptibility studies of two endemic North American (P. setiferus and P. aztecus) and one Asian penaeid species (P. chinensis) showed that P. aztecus and P. chinensis juveniles were susceptible, whereas, P. setiferus appeared refractory to TSV infection. The geographic range of TSV within the Americas was documented based on gene probe and histological findings of archived P. vannamei samples dating from 1992 to 1996. TSV was detectable within P. vannamei submitted from Ecuador when the disease was first recognized (1992) and has since spread into 12 other countries. The causes and effects of the international controversy of a viral versus a toxic etiology for TS are discussed and a solution offered to prevent similar disputes in the future.

Multiple studies were conducted to evaluate management options for cows in a thermal stress environment. Those options included cooling to enhance cow comfort, recombinant bovine somatotropin (rbST; Posilac®) to potentially increase milk production, and reproductive hormone scheduling to theoretically coordinate follicular growth leading to ovulation. In the first series of trials measuring the effects of cooling and rbST on milk yield, reproductive performance, and health in Jersey cows during two summer of thermal stress, cows were divided into on of two pens. Both Year 1 and Year 2 control cows (n = 143 and n = 183, respectively) were housed in a pen with no cooling other than shade. The cooled treatment cows each year (n = 142, n = 180) were housed in a pen utilizing the Universal Fog cooling system. One half of the cows in each group was assigned to receive rbST on d 63 postpartum (pp). Cows were assigned to the trial at various days pp, but no cow was assigned prior to d 63, coincident with commencement of rbST injections. The main effect for cooling in combination with rbST increased milk yield compared to no cooling and no rbST for 1999 and 2000 (25.5 vs 21.8 kg/d, and 23.7 vs 20.5, respectively; P < 0.05). Cooling and rbST effects on milk yield were additive the first year, but had a synergistic interaction the second year. Incidences of mastitis (8 vs 17; P < 0.05) for both years and laminitis (2 vs 7; P < 0.05) for Year 1 were both reduced. Reproductive performance was improved in cows given access to cooling (126 pregnant and 6 abortions) vs shade only (112 pregnant vs 13 abortions) in Year 1 (P < 0.05). Additional income over cooling cost was 67¢/cow per day for Year 1 and 52¢/cow per day for Year 2. In the second series of experiments, Holstein and Brown Swiss cows at 56 ± 3.5 d pp were used to evaluate ovulation rates over three seasons, including two summers when half the cows were cooled. All cows received rbST beginning d 63 ± 3.5 pp regardless of treatment. For Exp.1, 58 cows were assigned at calving, beginning June 1, 1999, to either a cooled (Korral Kool™) or non-cooled (shade only, control) pen. At d 56 ± 3.5 pp, all cows commenced a hormonal program coined Select Synch, comprised of an injection of GnRH (100 μg) agonist (Factrel®) followed 7 d later with an injection of PGF₂α (25 mg In-Synch™), at which time ultrasonography was initiated and continued until ovulation or follicular turnover. Experiment 2 was conducted the same as Exp. 1, with the assignment of cows starting Nov. 1, 1999. In Exp.3, all cows were assigned the same as Exp. 1 and 2 beginning June 1, 2000. At d 56 ± 3.5 pp, cows were scheduled to commence Ovsynch, which was identical to Select Synch, except a second Factrel® injection was administered 33 h after 35 mg Lutalyse®. Ultrasonography was the same as described above. Ovsynch led to a higher frequency of ovulations for the non-cooled and cooled cows (77.3 and 69.6%, respectively), than Select Synch for the non-cooled, cooled, and winter treatments (27.6, 24.1 and 29.4%, respectively). Ovulation frequencies were related more to hormonal programming rather than the season.

In this thesis the statistical analyses that were used to study the by now well known bovine spongiform encephalopathy (BSE) epidemic are reviewed. Central to the analysis is a backcalculation survival model whose development is discussed in detail. Various techniques applied to examining the likelihood of a maternal infection route (in addition to the main feed infection route) are discussed. It is found that maternal transmission is likely to occur at low rates. Measures taken to eliminate meat and bone meal feed supplements, the main infection source, have essentially eliminated BSE. However, the magnitude of the latent effect of tainted meat on humans in the form of the linked new variant Creutzfeldt-Jacob disease is yet to be assessed.

Lipopolysaccharide (LPS) from Gram-negative bacteria triggers a protective inflammatory response in a normal host. In classical laboratory inbred strains of mice, the Lps locus controls the rate of exponential Salmonella growth in spleen and liver during the early phase of infection through its effect on innate immunity. The gene encoding the Lps mutation was recently identified as the Toll-like receptor 4 (Tlr4 ). Toll-like receptors are a group of evolutionarily conserved pattern recognition receptors involved in the activation of the immune system in response to pathogen. The discovery of mouse Tlr4 as being the gene encoding the Lps mutation provided the possibility of studying the role of this gene in chicken susceptibility to infection with Salmonella typhimurium. To achieve this goal we have cloned the chicken orthologue of mouse Tlr4, determined its sequence, mapped it in the chicken genome and showed its linkage to susceptibility to infection with Salmonella typhimurium in the chicken.

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6121. Adviser: James K. Drackly. Includes bibliographical references. Available on microfilm from Pro Quest Information and Learning.

Bovine tuberculosis, caused by Mycobacterium bovis, infects approximately 50 million cattle worldwide and is diagnosed by the tuberculin skin test (TST). The purpose of this thesis was to characterise the culture filtrate proteins (CFP) of M. bovis PPD tuberculin and to compare the antibody response of M. bovis infected versus M. bovis sensitized cattle. Sterile filtered PPD tuberculin (SF-PPD) resolved into approximately 200 discrete spots using two-dimensional PAGE. While 2D Western blot analysis of both M. bovis sensitized and M. bovis infected cattle sera demonstrated an antibody boost following comparative intradermal TSTs, M. bovis sensitized cattle responded with greater intensity to additional SF-PPD antigens as compared to M. bovis infected cattle at seven weeks post infection/sensitization. In conclusion M. bovis sensitized cattle generated a more intense antibody response and recognized additional SF-PPD antigens as compared to M. bovis infected cattle within the first two months post infection/sensitization.

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