Thesis (Ph.D.)--University of Nebraska-Lincoln, 2008. / Title from title screen (site viewed Jan. 13, 2009). PDF text: vii, 268 p. : col. ill. ; 5 Mb. UMI publication number: AAT 3321565. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 75-84).

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 39-44).

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 54-58). Also available on the World Wide Web.

Bovine viral diarrhea virus (BVDV) is a pestivirus that suppresses the innate and adaptive host immune responses. Each of the two classified genotypes (BVDV1 and BVDV2) has two distinct biotypes – cytopathic (cp) and non-cytopathic (ncp) – and evidence has suggested that cytopathic strains may disrupt host interferon (IFN) synthesis and IFN-mediated responses. However, inconsistent results examining ncpBVDV strains have generated controversy regarding whether they also exhibit this capability. The purpose for this study was to determine the occurrence and functionality of IFN-induced responses within the serum cattle infected with ncpBVDV2-1373. Specifically, this involved analysing the changes in both the serum levels of IFN-α and IFN-γ and the expression of genes that are classically regulated by these cytokines. Serum analysis showed that the infected cattle induced both serum IFN-α and IFN-γ during BVDV infection while PBMC analysis showed increased expression of genes that classically respond to IFN-α – Mx-1, OAS-1, and STAT-1 – and IFN-γ – SOCS-1 and SOCS-3. These findings are supported by temporal kinome analysis, which verified activation of the JAK-STAT signalling network within the PBMCs of the virus-infected animals. In addition to establishing evidence for its synthesis, results from this challenge identified IFN-γ as a possible indicator of animal mortality as analysis of its change within the non-surviving, infected animals was statistically greater than the levels of the surviving, infected animals. Collectively, these results demonstrate 1373-mediated induction of, and host cell response to, both IFN-α and IFN–γ, and the potential for IFN-γ to be a predictive marker for mortality during BVDV infection.

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.

Thesis(M.S.)--Auburn University, 2005. / Abstract. Vita. Includes bibliographic references.

Thesis (M.A. in veterinary science)--Washington State University, May 2009. / Title from PDF title page (viewed on Apr. 23, 2010). "Department of Veterinary Clinical Sciences." Includes bibliographical references (p. 83-89).

Resumo: O Vírus da Diarréia Viral Bovina (BVDV) é um dos patógenos mais importantes na pecuária bovina em todo mundo, principalmente por desencadear manifestações clínicas relacionadas à esfera reprodutiva. A infecção em fêmeas gestantes pode resultar em abortamentos, reabsorções embrionárias, mumificações fetais, má formações e nascimento de bezerros fracos além do aparecimento de animais persistentemente infectados e imunotolerantes ao vírus, que são a principal fonte de infecção e disseminação da doença nos rebanhos. Atualmente, a complexidade do diagnóstico e consequentemente a patogenia, estão relacionados às diferenças genotípicas do agente. Por isso, a presente pesquisa teve como objetivo verificar a ocorrência dos genótipos BVDV-1 (Singer) e BVDV-2 (VS-253) em vacas, e respectivos fetos, abatidas em um frigorífico no Estado de São Paulo por meio da análise do soro sanguineo por meio da técnica de virusneutralização. No contexto geral, 52,51% (115/219) das vacas testadas foram reagentes, mas nenhum feto (0/219) reagiu na virusneutralização. Pela análise cruzada conforme a estirpe viral, observou-se que 42% (92/219) das vacas foram reagentes tanto para o genótipo BVDV-1 como para o genótipo do BVDV-2. Por outro lado 4,10% (9/219) reagiram apenas para o genótipo BVDV-1 e 6,39% (14/219) reagiram apenas para o genótipo do BVDV 2. Notou-se portanto que ambas as estirpes estão disseminadas nas regiões estudadas, fato que justifica o emprego de antígenos diferentes para evitar diagnóstico falso-negativo. Por fim, não foi observado qualquer alteração nos fetos que pudessem ser caracterizada como patologia da enfermidade. / Abstract: The Bovine viral diarrhea virus (BVDV) is one of the pathogens in bovine livestock worldwide most important mainly triggered by clinical manifestations related to the reproductive sphere. The infection in pregnant females may result in abortions, embryonic resorptions, fetal mummification, poor training, birth of weak calves in addition to persistently infected and virus immunotolerant animals, which are the main source of infection and spread of the disease. Currently, the complexity to diagnosis and consequently to the pathogenesis are related genotypic differences that he presents. Therefore, this research aimed to verify the occurrence of BVDV- 1 (Singer) and BVDV-2 (VS-253) genotypes in cows and their respective fetuses slaughtered in a abattoir at the state of São Paulo by analyzing the blood serum using virusneutralization technique. In the general context, 52.51% (115/219) of cows were reagents, but no fetus (0/219) reacted in virusneutralization. After a cross-examination we observed that 42% (92/219) of cows reacted for both BVDV-1 and BVDV-2 genotype. Furthermore 4,10% (9/219) reacted only to the genotype BVDV-1 and 6,39% (14/219) responded only to the genotype 2 of BVDV. It was noted therefore that both strains are widespread in the regions studied, which also justifies the use of different antigens to avoid false-negative diagnosis. Finally, there was no change in fetuses that could be characterized as a pathology of the disease. / Orientador: Samir Issa Samara / Coorientador: Fabio Carvalho Dias / Banca: José Gabriel Amoril / Banca: Sandra Possebon Gatti / Mestre