Assessment of occurrence and diagnostic methods of viral diseases in cattle – viral diarrhoea (BVD), infectious bovine rhinotracheitis (IBR), rabies, enzootic bovine leukosis (EBL), and spongiform encephalopathy (BSE) – was carried out for the first time in Lithuania. It was established that viruses of rabies, infectious rhinotraheitis and viral diarrhoea are most widespread in the country. It was determined that occurrence of rabies in cattle is parallel with the infection of wildlife with rabies virus. Analysis of eradication programme of enzootic bovine leucosis was done. It revealed that only combined application of diagnostic and preventive measures allowed reducing the cattle infection up to 0.2%. Though bovine spongiform encephalopathy has not been recorded in Lithuania, it is feasible to implement its diagnostic and prevention programme. An overall financial analysis of expenditures on BSE and viral diseases diagnostics and control was for the first time done in Lithuania. It showed that BSE and EBL occupied the leading positions in the structure of expenditures on viral diseases. In 2001, expenditures on BSE investigations accounted for 76.68% and in 2004 for 86.74% of the total. Expenditures on EBL investigations relatively reduced from 86.98% in 2000 to 8.47% in 2004. During the time under consideration, expenditures on investigations of other viral diseases changed but little. It was determined that consistent and wide-scale preventive vaccination created... [to full text]

Orientador: Samir Issa Samara / Banca: Maria da Gloria Buzinaro / Banca: Fumio Honma Ito / Resumo: O presente trabalho teve como objetivo verificar a variação da ocorrência da Rinotraqueíte Infecciosa Bovina (IBR) pela associação com duas doenças virais imunossupressoras: a Diarréia Viral Bovina (BVD) e a Leucose Enzoótica Bovina (LEB), em seis propriedades onde não se adota esquema de vacinação contra essas enfermidades. Amostras de soro sangüíneo foram analisadas no teste de virusneutralização (VN), para constatação de IBR e BVD, e Imunodifusão em Gel de Ágar (IDGA), para a LEB. Foram selecionados cinco rebanhos bovinos, em propriedades localizadas em municípios dos Estados de São Paulo e Minas Gerais, sendo três de exploração leiteira, um de gado de corte e um misto, com animais soropositivos ao BoHV-1, além de um rebanho controle, sem anticorpos contra essa enfermidade. Das 278 amostras analisadas, 54,68% (152/278) foram positivas ao BoHV-1, 69,70% (194/278) ao BVDV-1 e 34,33% (96/278) ao VLEB. Na análise estatística, ao relacionar cada enfermidade com o tipo de exploração do rebanho e a idade dos animais, houve diferença significativa, indicando que estas variáveis são fatores de risco para as enfermidades estudadas. Em relação ao tipo de exploração, os rebanhos leiteiros foram mais suscetíveis ao BoHV-1 e a LEB (81,31% e 49,53% respectivamente, (α = 1 ) enquanto no rebanho de gado de corte o BVDV-1 teve maior ocorrência (94,74%, α = 1). A idade foi fator de risco apenas para o BoHV-1 e a LEB, sendo os animais mais velhos os mais suscetíveis (α = 1). As associações entre o BoHV-1 e o BVDV-1, e o BoHV-1 e a LEB também foram significativas (α = 5 e α = 1 respectivamente), indicando que em rebanhos infectados por BVDV-1 e/ou LEB, a probabilidade de se encontrar o BoHV-1 é maior do que naqueles onde não ocorre essas duas enfermidades. / Abstract: The present research had as objective to verify the variation of the occurrence of Infectious Bovine Rhinotracheitis (IBR) by association with two viral infections that affect the immune system, Bovine Viral Diarrhoea (BVD) and enzootic bovine leukosis (EBL), in six farms where vaccination against these diseases was not adopted. Serum samples had been analyzed by the virus neutralization (VN) test for IBR and BVD diagnosis, and agar gel immunodiffusion (IDGA) test for EBL diagnosis. Five cattle herds with BoHV-1 seropositive animals had been selected in the states of São Paulo and Minas Gerais, three of them exploiting dairy cattle, one exploiting beef cattle and one exploiting mixed cattle, in addition to a control herd without seropositive animals. From 278 analyzed samples, 54.68% (152/278) reacted to the BoHV-1, 69.70% (194/278) to the BVDV-1, and 34.33% (97/278) to the EBLV. The statistic analysis showed a significant difference (α = 1) in infection occurrence according to the kind of exploitation and the age of the animals. Dairy cattle were more sensitive to the BoHV-1 (81.31%) and to the EBLV (49.53%) and less to BVDV-1 infection (45.79%). Among the beef herds, the major occurrence was BVDV-1 infection (94.74%), followed by BoHV-1(34.19%) and EBLV (3.95%). The age was a risk factor (α = 1) only for BoHV-1 and EBLV. The associations between BoHV-1 and BVDV-1 infections (α = 5) and between BoHV-1 and EBLV infections (α = 1) also indicated that among BVDV-1 and/or EBLV infected herds the probability of finding BoHV-1 is higher than among herds where these two infections does not occur. / Mestre

O presente trabalho avaliou a efetividade do tratamento com tripsina (TT) na eliminação do BoHV-1 Colorado, causador da Rinotraqueíte Infecciosa Bovina (IBR). Camundongos fêmeas Swiss, com idade entre 6 e 8 semanas, foram superovuladas com 0,2mL a 5UI de hormônio eCG e, após 48h com hCG e acasaladas com machos inteiros da mesma linhagem e idade. Após 18 horas, as fêmeas foram eutanasiadas e, através de abertura no peritônio, os zigotos foram coletados. Foram separados zigotos para cinco ensaios que forneceram os seguintes dados: o BoHV-1 Colorado altera a taxa de clivagem e a morfologia do embrião; a tripsina, seguindo recomendações da IETS, não danifica o embrião; os embriões expostos aos vírus e submetidos ao TT não alteram sua morfologia e taxa de clivagem; foram detectados (nested-PCR+) vírus viáveis (MDBK+) após o TT. Estes resultados demonstram que o TT não foi efetivo para eliminar o BoHV-1 Colorado, porém em alguns ensaios o TT demonstrou eficiência na inativação do vírus o que torna-o um importante método de controle in vitro. / This study evaluated the effectiveness of treatment with trypsin (TT) in the elimination of BoHV-1 Colorado, which causes infectious bovine rhinotracheitis (IBR) Swiss female mice, aged 6 and 8 weeks, were superovulated with 0.2 mL 5UI hormone eCG and 48h after hCG and mated with males of the same lineage and age. After 18 hours, females were euthanized, and through na opening in the peritoneum, the zygotes were collected. Zygotes were separated for five trials that provided the following data: the Colorado BoHV-1 alters the cleavage rate and embryo morphology; trypsin, following recommendations of the IETS, does not damage the embryo; the embryos exposed to the virus and subjected to TT does not change their morphology and cleavage rate; were detected (nested-PCR +) viable virus (MDBK +) after the TT. These results demonstrate that TT was not effective to eliminate the BoHV-1 Colorado, but in some tests showed the TT efficiency in inactivating the virus makes it na important method of control in vitro.