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Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / Robert L. Larson / Bradley J. White / Bovine viral diarrhea virus (BVDV) is an endemic pathogen in the U.S. cow herd. The virus can cross the placental barrier and infect the unborn fetus. If infection occurs between 45 – 125 days of gestation, persistent infection (PI) in the unborn fetus is likely. Upon parturition, the PI calf is a lifelong shedder of BVDV significantly elevating the risk of viral exposure to non-PI cattle. Despite reports of significant production loss, many BVDV infections are subclinical and in some cases inconsequential. Our data has highlighted various factors potentially causing disparity in clinical outcomes following BVDV exposure including: variation of BVDV serum concentration among PI cattle which may influence the quantity of virus shed into the environment, preexisting BVDV immune (i.e. antibody) status among non-PI cattle, and the degree of stress experienced by non-PI cattle all may influence the susceptibility of disease. Additionally, cattle transiently infected (TI) with BVDV may temporarily shed BVDV thereby offering another source of exposure to non-PI cattle. Programs focusing on BVDV control and prevention consist of diagnostic tests to identify PI cattle, BVDV vaccines to reduce fetal infection and increase herd immunity, and biosecurity programs intended to prevent BVDV exposure to the resident herd. Survey work performed in Montana suggest that educating beef producers with regard to BVDV has significantly increased the implementation of these tools in order to reduce the risk of introducing BVDV to their resident herd. Despite the risk of production loss, the economic benefit of instituting whole-herd BVDV tests may vary due to herd prevalence. By utilizing Monte Carlo simulation, the current BVDV herd prevalence within the U.S. does not economically justify a nationwide BVDV eradication campaign. However, known BVDV positive herds and herds with an elevated likelihood (47%) of being BVDV positive displayed a positive economic outcome when whole-herd BVDV testing strategies were implemented across herd sizes of 50, 100, and 500 cows. The value of testing various testing modalities was dependent upon herd prevalence and herd size. These data suggest that veterinarians must critically evaluate the value of implementing whole herd testing protocols in U.S. beef herds.

The spontaneous rate of congenital cardiac defects in the commonly used Sprague-Dawley rat has not been extensively researched. The incidence of general congenital defects has been studied thoroughly and reported as very low incidence in this rat. Teratology studies using mammalian models are of increasing importance as the number of environmental contaminants increases. It is essential to know if the spontaneous congenital cardiac defect rate of this most common mammalian model in order to plan statistically appropriate research protocols. Using a thorough and detailed method of evaluating the structure of the Sprague-Dawley fetal rat heart, 624 fetal rat hearts were examined at term, just prior of delivery. The overall incidence of spontaneous congenital cardiac defects is 2.3%. This is similar to the incidence in man and thus enhances the suitability of the Sprague-Dawley rat as a small mammalian model for research into cardiac teratogenesis.

I studied Trichomonas gallinae, a flagellated protozoan that is the causative agent of the avian disease trichomoniasis. The purpose of my study was to assess (1) the incidence of trichomonads in wild birds, (2) the prevalence of trichomonads in water sources utilized by wild birds, and (3) possible methods to control the transmission of trichomonads in water sources utilized by wild birds. I trapped 403 birds during 1994 and 1995. Approximately 1/3 of these birds tested positive for T. gallinae, however, none exhibited any signs of lesions. I collected water samples from 10 bird baths, isolating flagellated protozoa from 2 of them. I could not identify the species of flagellated protozoa. I determined that high temperatures (50°C), near ultra-violet radiation, and natural sunlight are effective against trichomonads. In addition, the highest effective dilutions of Chlorox, Nolvasan, and distilled white vinegar active against trichomonads were determined.

In the Entoniscinae, five new genera are diagnosed, nine new species are described and two species, Paguritherium alatum Reinhard, 1945 and Synalpheion giardi Coutiere, 1908, are redescribed. The first record of an entoniscid from a stenopodid shrimp is reported. Also, the first records of entoniscids from two caridean shrimp families, the Hippolytidea and Palaemonidae, are reported. A new subfamily is proposed for the monotypic Diogenion Codreanu, Codreanu and Pike, 1960. A key to the genera of the Entoniscidae is presented as is a list of species of the Entoniscidae by host species. ftn*Originally published in DAI Vol. 51, no. 11. Reprinted here with corrected bibliographic information / acase@tulane.edu

The purpose of this dissertation was to characterize virulence, genomic and protein composition of a newly emerged virus of penaeid shrimp: white spot syndrome virus (WSSV). A partial genomic library, covering approximately 30-50% of the genome, of WSSV isolated from crayfish Orconectes punctimanus, was constructed by digesting viral DNA with endonuclease ClaI and cloning into the system pBluescript-JM109. Three viral inserts of approximately 2.2 kb, 2.8 kb and 6.3 kb, named as QW245, CR44, and QW237 respectively, were sequenced and analyzed. Six geographic isolates of WSSV, from China, India, Thailand, South Carolina, Texas, as well as from crayfish obtained from the US National Zoo in Washington D.C. were compared by electron microscopy (TEM) and SDS-PAGE. All viral isolates contained three major polypeptides of 25, 23 and 19 kDa. A fourth major polypeptide at the 14.5 kDa position was observed in four of the viral isolates. The 19 kDa polypeptide of the crayfish WSSV appeared larger in size than that of the other isolates. Amino acid composition of four of the major structural polypeptides of the South Carolina WSSV was analyzed. The NH₂ terminal amino acids of the 25, 23 and 14.5 kDa polypeptides of the SC WSSV were sequenced as MDLSFTLSVVTA, MEFGNLTNLDVA, and VARGGKTKGRRG, respectively. The genomic composition of the six geographic isolates of WSSV were compared by combining the methods of restriction analysis using nine endonucleases AccI, BglII, ClaI, BamHI, EcoRI, HindII, HaeI, SacI, XhoI and Southern blot hybridization applying three digoxigenin-11-dUTP labeled WSSV genomic probes LN4, C42 and A6. No distinctive difference among five WSSV isolated from penaeid shrimp was detected; differences were observed in the crayfish isolate of WSSV. The virulence of the six geographic isolates of WSSV were compared by per os challenge of Litopenaeus vannamei postlarvae and juveniles, and Farfantepenaeus duorarum juveniles. The Texas WSSV caused higher and more rapid mortalities; the crayfish WSSV caused lower and less rapid mortalities. L. vannamei postlarvae and juveniles were very susceptible to WSSV infection, while Fa. duorarum juveniles showed moderate resistance.

<p>The recent research focus on integrated multi-trophic aquaculture (IMTA) is redefining the aquaculture industry's approach to intensive aquaculture. More sustainable farm model systems that include multiple farm products with integrated trophic levels are being developed. While these systems may be economically and environmentally more sustainable, it is important to realize that integrating farm products also changes disease risk on farms. This is illustrated by examining how finfish disease risk can increase or decrease depending on the pathogen in a simple finfish / blue mussel (<i>Mytilus edulis</i>) IMTA system. Mussels bio-accumulate and repackage the opportunistic pathogen, <i>Vibrio anguillarum,</i> into infectious fecal particles increasing the potential risk of infection and creating new transmission pathways. In contrast, mussels appear to inactivate the viral pathogen, Infectious Salmon Anemia Virus (ISAV) and potentially serving a role in reducing the transmission of the virus onto and off of IMTA farms. </p><p> To understand disease risk on IMTA farms, it is no longer adequate to simply investigate how a given pathogen interacts with its host under a range of environmental conditions. Evaluating the disease risk in IMTA systems requires a better understanding of how pathogens may potentially interact with all of the components of the farm system, while recognizing new potential pathways that may be created or enhanced within and by the system its self. Through a more comprehensive understanding of these potential interactions farmers can apply a range of bio-security and best management practices to limit the risk of disease on IMTA farms. With good management IMTA farms should not increase the risk of disease, but may actually reduce the spread of pathogens in some situations. </p>

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3518. Adviser: Milton M. McAllister. Includes bibliographical references (leaves 73-99) Available on microfilm from Pro Quest Information and Learning.

I studied a population of Cooper's hawks (Accipiter cooperii) nesting in the metropolitan city of Tucson, Arizona, from 1994 to 1997. I identified 51 Cooper's hawk territories distributed across Tucson with pockets of nesting density as great as 1 pair/64.7 ha. Eucalyptus (Eucalyptus spp.) (70.8%), aleppo pine (Pinus halepensis ) (25.0%), and cottonwood trees (Populus fremontii) (4.2%) were used as nesting structures more frequently than expected based on availability. Nest trees were primarily located in residential yards (48.3%) and high-use recreational areas (28.3%). Nest sites had a greater basal area, canopy cover, stem density, and number of trees >10 m tall than random sites. I compared the breeding ecology of urban Cooper's hawks with those in exurban areas. Urban pairs tended to have larger clutches (urban x̄ = 3.64: exurban x̄ = 3.20) (P = 0.085) and more nestlings (urban x̄ = 3.11; exurban x̄ = 2.78) (P = 0.145) than exurban pairs. Nestling mortality, however, was greater among urban nests (51%) than exurban nests (5%). The primary cause of death among urban nestlings was trichomoniasis (80%), a disease caused by the parasitic protozoan Trichomonas gallinae ; the disease was not a mortality factor among exurban nests. Raptors develop the disease by eating infected prey. Doves (Columbidae) are hosts for the protozoan and accounted for 83% and 10% of the diet of urban and exurban Cooper's hawks, respectively. Breeding age Cooper's hawks were 99% free of infection independent of nesting area. Infection rates were greater among urban nestlings than exurban nestlings (P < 0.0001). Breeding urban Cooper's hawks have high probabilities of survival (0.792) and recapture (0.947), but the estimated juvenile survivorship is low (0.199). Age-specific fecundity and survival suggests the urban population is declining by 8% annually, but has the capacity to increase by at least 2% annually. Paradoxically, the population appears to be stable or increasing, probably due to immigration of Cooper's hawks from outside the study area. Population sinks in human altered landscapes have been described as "ecological traps" because animals are attracted to them but suffer from low productivity or high mortality once they are there. My results suggest Tucson may be an ecological trap for Cooper's hawks.

Master of Science / Department of Animal Sciences and Industry / J. Ernest Minton / Enteric disease and immune challenge are processes that have detrimental effects on growth performance of young swine. The current study tested the hypothesis salmonellae-induced enteric disease would perturb the endocrine growth axis in a serovar dependent fashion. Specifically, we evaluated effects of Salmonella enterica serovar Typhimurium (Typhimurium) and serovar Choleraesuis (Choleraesuis) on critical regulatory components of growth in young swine. Weaned pigs were housed 2 per pen with ad libitum access to feed and water in a 14 d experiment. Pigs were then repeatedly fed either 10[superscript]8 CFU Choleraesuis or 10[superscript]8 Typhimurium in dough balls, with control pigs receiving dough without bacteria. Bacteria were re-fed twice weekly. Rectal temperatures were monitored daily from d 0 to7 and ADFI was measured through d 14. Pigs were weighed and samples of serum were obtained for circulating IGF-I on days 0, 7, and 14. At the conclusion of the study, samples of semitendinosus muscle and liver were obtained and subsequently assayed for IGF-I, IGFBP-3, and IGFBP-5 mRNA. Rectal temperatures were elevated in pigs given Choleraesuis pigs from d 2 through d 7 (P < 0.05) when compared to control pigs and pigs fed Typhimurium. Pigs receiving Choleraesuis had substantially decreased feed intake on days 2, 3, 4, 7, 8, 9, and 10 (P < 0.01), with a trend for reduction on d 5 (P = .08), and they experienced an approximate 25% reduction in BW compared to control and Typhimurium pigs by the conclusion of the study. Pigs given Choleraesuis also experienced marked reductions in circulating IGF-I on d 7 (P < 0.01 vs. control and Typhimurium) with reductions of lesser magnitude on d 14 (P = 0.07 vs. control and P < 0.05 vs. Typhimurium). Treatment tended to affect liver IGFBP-3 mRNA (P = 0.08), where expression tended to be elevated in Typhimurium and Choleraesuis pigs. In contrast, IGFBP-3 mRNA relative abundance was increased (P < 0.03) in pigs given Typhimurium versus control pigs. Muscle IGF-I mRNA was reduced in Choleraesuis pigs compared to control and Typhimurium (P < 0.05). Treatment tended to affect muscle IGFBP-3 mRNA (P = 0.10), where Choleraesuis had numerically less relative abundance than controls. Oral inoculation of growing pigs with Choleraesuis disrupted feed intake and BW gain, and this was accompanied by decreases in circulating IGF-I and reduced muscle expression of mRNA for IGF-I and IGFBP-3.