• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 11
  • 11
  • 11
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 2
  • 1
  • Tagged with
  • 47
  • 47
  • 11
  • 10
  • 9
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Diagnóstico e caracterização molecular de Giardia duodenalis e Cryptosporidium spp. em amostras fecais de bovinos e ovinos /

Silva, Flávio Medeiros Paz e. January 2007 (has links)
Resumo: Os protozoários Giardia duodenalis e Cryptosporidium spp. são comprovadamente patógenos potenciais para bovinos e ovinos (particularmente em bezerros e cordeiros). Recentemente, o uso de técnicas moleculares demonstrou que Giardia duodenalis e Cryptosporidium spp. são espécies compostas de populações morfologicamente indistinguíveis, porém com grande diversidade genética. Os isolados de Giardia duodenalis obtidos de amostras fecais de ruminantes podem pertencer a grupos genéticos hospedeiro-específicos (genótipo E) ou a grupos genéticos potencialmente zoonóticos (genótipo A e B). Quatro espécies/genótipos de Cryptosporidium spp. com diferenças biológicas e genéticas consideráveis, são capazes de infectar bovinos: Cryptosporidium parvum, Cryptosporidium andersoni, Cryptosporidium bovis e Cryptosporidium genótipo deer-like. Em ovinos uma longa lista de espécies/genótipos tem sido identificados, alguns dos quais ainda são descritos como espécies/genótipos desconhecidos. O objetivo desse estudo foi determinar a ocorrência de Giardia duodenalis e Cryptosporidium spp. em 10 propriedades de bovinos leiteiros e 1 propriedade de ovinos no Estado de São Paulo, realizando o diagnóstico por meio das técnicas de microscopia óptica (Centrifugo-flutuação em sulfato de zinco modificada e coloração por fucsina carbólica modificada), Ensaio imunoenzimático (ELISA) e Reação em Cadeia da Polimerase (PCR); e caracterizando geneticamente esses protozoários com o emprego da técnica de polimorfismo no tamanho dos fragmentos de restrição (RFLP). A ocorrência de Giardia duodenalis e Cryptosporidium em 200 bovinos foi de 8 e 14%, respectivamente. O diagnóstico das infecções em bezerros foi significativamente maior do que em animais adultos. A técnica da PCR demonstrou uma sensibilidade diagnóstica superior quando comparada às técnicas de microscopia óptica e ensaio imunoenzimático. / Abstract: Giardia duodenalis and Cryptosporidium spp. are protozoan organisms that can infect the intestinal tract of many animal species including mammals. Clinical signs reported in calves and lambs infected with theses parasites include dullness, lethargy, anorexia, fever, dehydration, gastritis, reduced milk yield and poor weight gain and therefore have a potential clinical and economic impact. Despite morphological uniformity, considerable biotypic and genetic diversity exists within the G. duodenalis and Cryptosporidium species. G. duodenalis is a species complex comprising at least seven major assemblages or genotypes (A, B, C, D, E, F and G). These assemblages, which differ from each other significantly, appear to have distinct host preferences or have a limited host range. Recent studies suggest that cattle are infected with at least four Cryptosporidium parasites: C. parvum, Cryptosporidium bovis, Cryptosporidium andersoni and the Cryptosporidium deer-like genotype . In sheep, however, most prevalence information is based on microscopy and thus there is little information on Cryptosporidium species or genotypes. This study was undertake to determine the occurrence of Giardia and Cryptosporidium infections in dairy cattle and sheep in São Paulo State, Brazil through the use of microscopy, Enzyme Immunoabsorbent assay (EIA) and Polymerase chain Reaction (PCR); and to determine the species/genotypes by PCR-RFLP. Ten dairy farms in Botucatu city region are sampled. At each farm, 20 specimens are randomly collected. Giardia and Cryptosporidium was identified in 80% and 90% of farm locations, respectively. Of the 200 specimens collected, 8% and 14% has Giardia and Cryptosporidium DNA, respectively. Most infections were Giardia duodenalis Assemblage E (87,5%) and Cryptosporidium andersoni (82%) which are not zoonotic; however, one calf was infected with zoonotic Giardia duodenalis Assemblage AII and another with B. / Orientador: João Pessoa Araújo Júnior / Coorientador: Raimundo Souza Lopes / Banca: Alessandro Francisco Talamini do Amarante / Banca: Katia Denise Saraiva Bresciani / Mestre
22

Diagnóstico e caracterização molecular de Giardia duodenalis e Cryptosporidium spp. em amostras fecais de bovinos e ovinos

Silva, Flávio Medeiros Paz e [UNESP] 21 June 2007 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-06-21Bitstream added on 2014-06-13T19:11:24Z : No. of bitstreams: 1 silva_fmp_me_botfmvz.pdf: 2999608 bytes, checksum: 16c0ff22e39cd5714270de54e0384c11 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os protozoários Giardia duodenalis e Cryptosporidium spp. são comprovadamente patógenos potenciais para bovinos e ovinos (particularmente em bezerros e cordeiros). Recentemente, o uso de técnicas moleculares demonstrou que Giardia duodenalis e Cryptosporidium spp. são espécies compostas de populações morfologicamente indistinguíveis, porém com grande diversidade genética. Os isolados de Giardia duodenalis obtidos de amostras fecais de ruminantes podem pertencer a grupos genéticos hospedeiro-específicos (genótipo E) ou a grupos genéticos potencialmente zoonóticos (genótipo A e B). Quatro espécies/genótipos de Cryptosporidium spp. com diferenças biológicas e genéticas consideráveis, são capazes de infectar bovinos: Cryptosporidium parvum, Cryptosporidium andersoni, Cryptosporidium bovis e Cryptosporidium genótipo deer-like. Em ovinos uma longa lista de espécies/genótipos tem sido identificados, alguns dos quais ainda são descritos como espécies/genótipos desconhecidos. O objetivo desse estudo foi determinar a ocorrência de Giardia duodenalis e Cryptosporidium spp. em 10 propriedades de bovinos leiteiros e 1 propriedade de ovinos no Estado de São Paulo, realizando o diagnóstico por meio das técnicas de microscopia óptica (Centrifugo-flutuação em sulfato de zinco modificada e coloração por fucsina carbólica modificada), Ensaio imunoenzimático (ELISA) e Reação em Cadeia da Polimerase (PCR); e caracterizando geneticamente esses protozoários com o emprego da técnica de polimorfismo no tamanho dos fragmentos de restrição (RFLP). A ocorrência de Giardia duodenalis e Cryptosporidium em 200 bovinos foi de 8 e 14%, respectivamente. O diagnóstico das infecções em bezerros foi significativamente maior do que em animais adultos. A técnica da PCR demonstrou uma sensibilidade diagnóstica superior quando comparada às técnicas de microscopia óptica e ensaio imunoenzimático. / Giardia duodenalis and Cryptosporidium spp. are protozoan organisms that can infect the intestinal tract of many animal species including mammals. Clinical signs reported in calves and lambs infected with theses parasites include dullness, lethargy, anorexia, fever, dehydration, gastritis, reduced milk yield and poor weight gain and therefore have a potential clinical and economic impact. Despite morphological uniformity, considerable biotypic and genetic diversity exists within the G. duodenalis and Cryptosporidium species. G. duodenalis is a species complex comprising at least seven major assemblages or genotypes (A, B, C, D, E, F and G). These assemblages, which differ from each other significantly, appear to have distinct host preferences or have a limited host range. Recent studies suggest that cattle are infected with at least four Cryptosporidium parasites: C. parvum, Cryptosporidium bovis, Cryptosporidium andersoni and the Cryptosporidium deer-like genotype . In sheep, however, most prevalence information is based on microscopy and thus there is little information on Cryptosporidium species or genotypes. This study was undertake to determine the occurrence of Giardia and Cryptosporidium infections in dairy cattle and sheep in São Paulo State, Brazil through the use of microscopy, Enzyme Immunoabsorbent assay (EIA) and Polymerase chain Reaction (PCR); and to determine the species/genotypes by PCR-RFLP. Ten dairy farms in Botucatu city region are sampled. At each farm, 20 specimens are randomly collected. Giardia and Cryptosporidium was identified in 80% and 90% of farm locations, respectively. Of the 200 specimens collected, 8% and 14% has Giardia and Cryptosporidium DNA, respectively. Most infections were Giardia duodenalis Assemblage E (87,5%) and Cryptosporidium andersoni (82%) which are not zoonotic; however, one calf was infected with zoonotic Giardia duodenalis Assemblage AII and another with B.
23

Streptococcus dysgalactiae polyarthritis in lambs in England and Wales

Rutherford, Sarah-Jayne January 2011 (has links)
No description available.
24

Studies on the spring rise phenomenon in ovine helminthiasis.

Procter, Bryan George. January 1966 (has links)
No description available.
25

A biochemical and immunological comparison of the Jaagsiekte and two related retroviruses.

York, Denis Francis. 25 September 2013 (has links)
Jaagsiekte is a contagious cancer affecting the lungs of sheep. Although the etiological agent is Jaagsiekte retrovirus (JSRV), two other retroviruses viz South African maedi visna virus ( SA - OMVV) and a novel Bovine retrovirus (BRV) have been associated with or implicated in the jaagsiekte disease complex. JSRV was sufficiently purified from lung rinse material using a Freon extraction, Percoll density gradient centrifugation and chranatography on a Sephacryl column, its polypeptide composition was studied by gel electrophoresis and its morphology observed electron microscopically. Monoclonal antibodies were made against purified preparations of the virus. Two hybridomas were isolated that produced MAbs which appear to be tumour cell specific. A third hybridoma, called 4A1O, produces antibodies considered to be viral specific. These MAbs have been used in the development of JS specific immunoassays. A cross reaction between JSRV and a polyclonal serum against Mason Pfizer monkey virus (MPMV) was confirmed and used in a Western blot technique to identify, monitor and differentiate JSRV from other viruses. During the study of JSRV it became apparent that another retrovirus was often present in JS infected lungs. This virus, referred to as SA - OM1V I, is a novel South African isolate of maedi visna virus (MVV). As SA - OM1V I has physicochemical characteristics similar to JSRV, it was often found in purified JSRV preparations. Being a retrovirus it is also detected by the reverse transcriptase assay which was the only method used to assay and monitor for JSRV during the early stages of our work. Using a Westen blot technique and sera against MVV and MPMV it was possible to simultaneously detect and differentiate JSRV from SA - OMVV I. A method was also developed whereby the two viruses could be separated from each other during purification. The information gained and techniques developed whilst studyiing JSRV were also used to isolate and characterize BRV. This novel virus originated from bovine cells that had been co-cultivated with white blood cells from an ox suffering from malignant catarrhal fever. Three out of four sheep inoculated with BRV developed JS. It therefore had to be· ascertained whether this virus was related to JSRV or not. The comparative study revealed that BRV was biochemically and morphologically quite different fran JSRV. Interestingly, it was shown that serum against MPMV cross reacted with a 32 kd protein of BRV indicating a serological relationship between JSRV, MPMV and BRV. The possible role of BRV in the etiology of jaagsiekte remains to be elucidated. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1987.
26

The pathophysiology of Sarcocystis tenella infections in specific-pathogen-free (sporozoa) sheep / by Peter Harry Phillips.

Phillips, Peter Harry January 1982 (has links)
Some ill. mounted. / Bibliography: leaves [473]-504. / xxxvi, 505 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Pathology, 1984
27

Investigating novel aspects of FMDV pathogenesis in pregnant ovines, foetuses and neonatal lambs

Waters, Ryan Andrew January 2012 (has links)
No description available.
28

Contagious ecthyma virus infection of sheep: virologic and immunologic investigations

Buddle, Bryce Malcolm January 1981 (has links)
Outbreaks of contagious ecthyma (CE) have been reported in vaccinated sheep and studies were undertaken to investigate the causes of these vaccination failures. The vaccination procedure was very effective in inducing a lesion at the site of vaccination, but a proportion of sheep (17 percent) were not fully protected when reinoculated with CE virus 4 weeks later. The size of the primary vaccination lesions, virus neutralizing antibody titers and virus-specific lymphocyte stImulation indices could not be used to predict the degree of protective immunity. Measurement of the neutralizing antibody and virus-specific lymphocyte transformation responses suggested that there was a minimal systemic immune response following CE virus inoculation. Higher levels of systemic immunity may be induced by parenteral administration of live CE vaccines compared to the current procedure of inducing a localized skin infection. Replication of CE virus in buffy coat cells in vitro suggested that the virus may replicate in macrophages and therefore parenteral administration of vaccines may be feasible. Occurrence of CE in vaccinated sheep raised questions about possible variation of antigenic types of CE virus. It was found that cross-neutralization and delayed-type hypersensitivity tests could not be used to classify the CE viral isolates. However, analysis of the structural polypeptides of CE virions revealed differences among the isolates in the position of distinct polypeptide bands in the molecular weight region of 37,000-44,000 daltons, allowing the isolates to be classified into four groups. The polypeptides which varied among the different groups were shown to be located in the surface component of the virion. Unilateral cross reactions detected in cross-neutralization tests were found to correlate with classification of the isolates based on the position of the distinct polypeptide bands. Cross-immunity tests were performed in lambs using two isolates which did not cross-react in the cross-neutralization tests and in which differences in the polypeptide profiles were detected. Reinoculation with virulent sheep-passaged CE viruses overcame the immunity of the lambs. By contrast, there was protection against the less virulent cell culture-passaged CE viruses with cross-protection between the two isolates. These results suggest that virulent CE viral isolates may be responsible for the occurrence of CE in vaccinated animals rather than differences in antigenicity. Two epidemiological aspects of CE infection of sheep were also studied. Latent CE infections were investigated by treating CE-inoculated sheep with corticosteroids. Treatment induced recrudescence of lesions at sites of previous CE virus inoculation, but virus could not be isolated from these lesions. Hence, the existence of latent infections could not be confirmed, but it is unlikely that latent infections are important for the initiation of CE disease outbreaks. Importance of colostral immunity was investigated with ewes vaccinated 6 months prior to parturition. This vaccination did not result in sufficient colostral immunity to protect lambs from subsequent exposure to CE virus, however, the severity of the CE lesions may have been reduced. / Ph. D.
29

Oogenesis of Ostertagia circumcincta, a parasitic namatode of the abomasum of sheep

Groseclose, Nancy P. January 1939 (has links)
Ostertagia circumcincta, a parasitic nematode of sheep, known collectively with the O. trifuroata, the smaller trichostrongyles and several other worms of the same genus Ostertagia, as the "brown hair worms of sheep”, has held a rather obscure position in the evaluation of the importance of the sheep and goat parasites. This fact and their small size account for the elusive past of this nematode. The status of economic importance, however, to which O. circumcincta has now risen, not only in this state, but in the western section of the United States, Europe, New Zealand, and Australia, suffices as an explanation tor further researches bearing on the classification, anatomical organization and cytological study of this parasite. This paper deals quite briefly with the anatomy of the female Ostertagia circumcincta, and somewhat more in detail with the changes observed in the development of the germ cells from the primordial stage through the first cleavage division. 1. The primordial germ cells arise at the tip of the germ tube which lies just posterior to the oesophagus. 2. The period of growth following each stage in the development of the egg is accompanied by a fragmentation of the chromatin material before division takes place. 3. Chromatin strands make their first appearance in the secondary oocytes. 4. The chromatin strands condense to form six bivalent chromosomes or tetrads. 5. The six tetrads split to form twelve individual chromosomes then fuse to form six bivalents which are present when the egg enters the seminal receptacle. N=6 2N=12 6. The eggs remain in one-celled stage until they reach the seminal receptacle where fertilization takes place; immediately thereafter, that is to say, in the uterus. They begin their cleavage divisions. / Master of Science
30

Effect of monensin supplementation on ruminal and postruminal digestion in sheep and on adaptation of ruminal microbes

Rogers, Michaela G. January 1987 (has links)
Three experiments were conducted to examine the effects of an ionophore, monensin sodium, on digestion in sheep. The first experiment was concerning alterations induced by long-term supplementation and subsequent withdrawal of the ionophore. The diet was a pelleted mixture of 43% native prairie hay, 34% corn grain, and 21% lupin grain plus 100 g wheat straw. Monensin (33 ppm) was added to the diet of four wethers, and four other animals served as controls and consumed an identical diet. without monensin. Monensin supplementation increased (P <.05) ruminal propionate while decreasing (P <.05) acetate levels throughout the 146-d experiment. Withdrawal caused acetate to return to control levels but decreased (P <.05) propionate. During ionophore supplementation, the digestibilities of organic matter (OM) and dry matter (DM) were increased (P <.05) by an average of 8 and 9%, respectively. Apparent digestibility ' of N was increased from 75 to 77% after 19 d of supplementation. There was an augmentation (P <.05) in the flow of bacterial N at the duodenum after 96 d of supplementation. This effect disappeared with ionophore withdrawal. In a second experiment, the effect of monensin on postruminal digestion was examined in three trials with six wethers. There were three treatments: control, dietary monensin, and monensin infused into the duodenum. The diets were the same as in the previous experiment. Dietary monensin caused the same changes in ruminal VFA as in the previous experiment. Infused monensin had no effect on VFA. Dietary monensin increased (P <.05) trypsin activity at the ileum. Dietary ionophore did not alter nutrient digestibilities, but shifted (P <.O5) the site of OM and DM digestion from the cecum to before the terminal ileum by 14 and 10%, respectively. In an in vitro experiment rumen contents from monensin-adapted and nonadapted sheep were compared with and without additional ionophore in a 6 h incubation system. Rumen contents from adapted sheep did not differ from contents of nonadapted sheep in the quantity of microbial N synthesized. With monensin addition to the incubation, microbial synthesis dropped by 49% in nonadapted microorganisms. In adapted contents, the decrease in synthesis was only 9%. Monensin-adapted microbes degraded (P <.O1) more protein substrate than those which were not adapted. / Ph. D. / incomplete_metadata

Page generated in 0.0383 seconds