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1.
Townsend KM Hanh TX O'Boyle D Wilkie I Phan TT Wijewardana TG Trung NT Frost AJ 《Veterinary microbiology》2000,72(1-2):69-78
A total of 36 tonsil swab samples were collected from healthy swine prior to slaughter at the abattoirs in Can tho and Tien giang provinces of Southern Vietnam. The presence of Pasteurella multocida in these samples was detected by the combination of direct cultivation and isolation, mouse inoculation and the polymerase chain reaction (PM-PCR). P. multocida was detected in 16 samples by PCR, with 17 strains ultimately isolated. All samples were negative for serogroup B by HSB-PCR and conventional serotyping, with isolates identified as A:3, D:1 or D:3. In addition, all samples were determined to be negative for the P. multocida toxin (PMT). Characterisation of isolated P. multocida by REP-PCR and biotyping revealed nine distinct REP profiles and seven biotypes among the 17 isolates. Some correlation was seen with P. multocida isolated from a previous Australian outbreak of acute swine pasteurellosis, and those isolated from fowl cholera outbreaks in Vietnamese poultry. 相似文献
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TG McEvoy 《Reproduction in domestic animals》2003,38(4):268-275
Assisted reproductive technologies, as applied to domestic animals, can exert both novel and wide‐ranging influences on the development, viability and welfare of offspring. Some of the changes are evident immediately or soon after the time at which a manipulative procedure is carried out, while other changes may not be evident until later in development or, perhaps, may remain undetected throughout an animal's lifetime. The present review explores some of the consequences – in terms of foetal, placental, neonatal and post‐natal effects – of exposing embryos of cattle, sheep and other species to in vitro culture per se or, during culture, to physically invasive technologies including gene injection and nuclear transfer. The innate sensitivity of oocytes and recently fertilized eggs to their in vitro environment is illustrated by an examination of the later developmental repercussions resulting from apparently innocuous choices related to in vitro culture medium formulations. In contrast, an inherent resilience and paradoxical readiness to resume development following the traumas of nuclear transfer procedures is also in evidence. The extent to which assisted reproductive technologies will succeed, where relevant, in the domestic animal sector will be influenced by our appreciation of embryo requirements, for both short‐ and long‐term developmental fitness, during their earliest developmental stages. Evidence of species‐specific needs is testimony to the challenges ahead. Ultimately, our ability and inclination to resolve the limitations associated with current procedures will probably be greatly enhanced if predictive indicators (genetic, epigenetic or functional markers) of later developmental fitness can be identified. 相似文献
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SS Greening K Mulqueen TG Rawdon NP French MC Gates 《New Zealand veterinary journal》2020,68(5):261-271
ABSTRACT Aims: To collect baseline data on the contact risk pathways and biosecurity practices of commercial poultry farms in New Zealand, investigate the relationship between the farm-level disease contact risks and biosecurity practices, and identify important poultry health concerns of producers. Methods: A cross-sectional survey of all registered New Zealand commercial poultry operations was conducted in 2016 collecting information on farm demographics, biosecurity practices, and contact risk pathways. Survey responses were used to generate an unweighted subjective disease risk score based on eight risk criteria and a subjective biosecurity score based on the frequency with which producers reported implementing seven biosecurity measures. Producer opinions towards poultry health issues were also determined. Results: Responses to the survey response were obtained from 120/414 (29.0%) producers, including 57/157 (36.3%) broiler, 33/169 (19.5%) layer, 24/55 (44%) breeder, and 6/32 (19%) other poultry production types. Median disease risk scores differed between production types (p?<?0.001) and were lowest for breeder enterprises. The greatest risk for layer and broiler enterprises was from the potential movement of employees between sheds, and for breeder enterprises was the on- and off-farm movement of goods and services. Median biosecurity scores also differed between production types (p?<?0.001), and were highest for breeder and broiler enterprises. Across all sectors there was no statistical correlation between biosecurity scores and disease risk scores. Producers showed a high level of concern over effectively managing biosecurity measures. Conclusions: The uptake of biosecurity measures in the commercial poultry farms surveyed was highly variable, with some having very low scores despite significant potential disease contact risks. This may be related to the low prevalence or absence of many important infectious poultry diseases in New Zealand leading farmers to believe there is a limited need to maintain good biosecurity as well as farmer uncertainty around the efficacy of different biosecurity measures. Further research is needed to understand barriers towards biosecurity adoption including evaluating the cost-effectiveness of biosecurity interventions. 相似文献
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Sugiura K Akazawa T Fujimoto M Wijewardana V Mito K Hatoya S Taketani S Komori M Inoue N Inaba T 《Veterinary immunology and immunopathology》2008,126(3-4):388-391
To construct a vector for caspase-1 independent expression of canine IL-18, the signal sequence of canine IL-12p40 was fused to the sequence of mature IL-18 on the NdeI restriction site which is located at the 3' end of the signal sequence. The resulting vector expressed coding protein from transfected mammalian cells. The expressed protein was shown to have IL-18 bioactivity in a INF-gamma-inducing assay. These results suggest that the expression vector is the desired tool for advancement of dendritic cell (DC)-based cancer therapy, provided that the vector can successfully be transfected into dendritic cells. We propose a simple and widely applicable method for providing the signal sequence. 相似文献
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While much is known about the metabolism of exogenous nutrients such as glucose, lactate, pyruvate, amino acids by oocytes and pre-implantation mammalian embryos, the role of endogenous stores, particularly lipid, has been largely overlooked. The presence of lipid within oocytes and early embryos has been long known, and comparisons between species indicate that the amounts and types of lipid present vary considerably. Large amounts of intracellular lipid can compromise the success of cryopreservation and the removal of such lipid has been the subject of considerable effort. In this review, we present evidence that strongly suggests a metabolic role for lipid, specifically with regard to energy provision, in the late-stage oocyte and the pre-implantation embryo. We focus initially on oxygen consumption as a global indicator of metabolic activity, before reviewing different approaches that either have been designed to investigate directly, or have revealed indirectly the role of endogenous lipid in energy generation. These fall under five headings: (i) fatty acid oxidation; (ii) inhibition of triglyceride oxidation; (iii) culture in the absence of exogenous substrates; (iv) cytoplasmic organization; and (v) delipidation. On the basis of the data derived from these studies, we conclude that there is strong evidence for the utilization of endogenous lipid as an energy substrate by oocytes and early embryos. 相似文献
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M. C. L. de Alwis Thula G. Wijewardana Anoma I. U. Gomis A. A. Vipulasiri 《Tropical animal health and production》1990,22(3):185-194
Summary Fifty-seven young buffaloes were experimentally infected or naturally exposed to haemorrhagic septicaemia (HS). Of these animals 32 became immune carriers. They were observed in groups for periods up to 360 days to monitor the appearance of pasteurellae in the nasopharynx and antibody status. In most animals pasteurellae appeared in the nasopharynx for a short period initially and disappeared. The organism reappeared intermittently and the longest observed period of reappearance was 215 days after exposure. All animals showed rising antibody titres with a peak lasting for 150 to 180 days and declining thereafter. Pasteurellae persisted in the tonsils and were isolated from 20 out of 27 carriers after slaughter. The longest period when isolation was made after slaughter was 229 days. The organism lodged in the tonsils was unaffected by antibacterial therapy using drugs to which the organism displayedin vitro sensitivity. It is concluded that in HS, carrier animals exist in an active as well as a latent state, the former appearing for short intermittent periods between long latent periods, when pasteurellae continue to remain in the tonsils which constitute a long-term reservoir.
Persistencia Del Estado De Portador De Septicemia Hemorragica (Infeccion ConPasteurella Multocida Serotipo 6:B) Bufalos
Resumen Cincuenta y siete búfalos jóvenes fueron infectados experimentalmente o expuestos naturalmente a septicemia hemorrágica (SH). Treinta y dos de estos animales se volvieron portadores inmunes. Los búfalos fueron observados en grupos por períodos de hasta 360 días, para detectar la aparición de la pasteurela en la nasofaringe y de anticuerpos. En la mayoría de los animales la pasteurela apareció en la nasofaringe por un período inicial corto y desapareció. El organismo reapareció intermitentemente y el período más largo observado fue 215 días después de la exposición. Todos los animales tuvieron un aumento de anticuerpos, con un pico que duró de 150 a 180 días, declinando después. La pasteurela persistió en las tonsilas y fue aislada en 20 de 27 portadores después del sacrificio. El período más largo de aislamiento, después del sacrificio, fue de 229 días. El organismo alojado en las tonsilas, no fue afectado por terapia antibacterial, utilizando drogas a las cuales la bacteria fue sensitivain vitro. Se concluye que en SH, los animales portadores existen en estado activo y latente, apareciendo el primero por períodos intermitentes cortos, entre largos períodos latentes, cuando pasteurela se aloja en las tonsilas, las cuales constituyen un reservario permanente.
Persistance De La Situation De Porteur Chez Des Buffles Atteints De Septicemie Hemorragique APasteurella Multocida, Serotype 6:B
Résumé Cinquante sept jeunes buffles ont été infectés expérimentalement ou naturellement exposés à la septicémie hémorragique (HS). Parmi eux, 32 sont devenus des porteurs immuns. Ils ont été suivis par groupes pendant des périodes allant jusqu'à 360 jours pour déceler l'apparition de pasteurelles dans le nasopharynx et caractériser leurs taux d'anticorps. Chez la plupart des animaux, les pasteurelles sont apparues dans le nasopharynx pendant une courte période initiale puis ont disparu mais elles sont réapparues par intermittence et la période de présence la plus longue a été de 215 jours après le contact infectieux. Tous les animaux ont relevé des titres croissants d'anticorps avec un pic d'une durée de 150 à 180 jours suivi d'un déclin ultérieur. Les pasteurelles ont persisté dans les amygdales et ont été isolées sur 20 des 27 porteurs aprés abatage. La période la plus longue pendant laquelle l'isolement a pu être réalisé après abattage a été de 229 jours. L'organisme hébergé dans les amygdales a résisté a une thérapie antibactérienne avec des médicaments auxquels il se révélait sensiblein vitro. En conclusion, dans la septicémie hémorragique, il reste des porteurs actifs aussi bien que latents. Les premiers apparaissent par intermittence pendant des épisodes de courte durée, entre de longues périodes de latence, alors que les pasteurelles restent présentes dans les amygdales. Celles-ci jouent de ce fait le rôle d'un réservoir à long terme.相似文献
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Dissanayake DR Wijewardana TG Gunawardena GA Poxton IR 《Veterinary microbiology》2008,132(3-4):355-363
Five distinct lipopolysaccharide (LPS) core types, namely R1-R4 and K12 have been identified in Escherichia coli. The aims of this study were to determine, primarily by means of PCR, the distribution of those oligosaccharide core types among avian pathogenic E. coli and their relationship to phylogenetic groups. To identify putative avian pathogenic E. coli, serum resistance and the presence of three virulence genes encoding temperature sensitive haemagglutinin (tsh), increased serum survival (iss) and colicin V (cvaC) were determined. Of the 143 clinical isolates examined 62% possessed the R1 core, 22% were R3, 13% were R4 and 3% were R2. Fifty commensal isolates consisted of 58% with R1 core, 38% with R3 core, 4% with R4 core, and none with R2. None of the isolates were of K12 core type. The distribution of core oligosaccharide types in clinical and commensal isolates were not statistically significant (P=0.51). Three genes, tsh, iss and cvaC were found in E. coli of all four core types. The genes tsh (P<0.001) and iss (P=0.03412) were significantly associated with the R4 core oligosaccharide type. The isolates containing R4 core type LPS were mainly confined to phylogenetic group D. The widespread R1 core type showed less ability to possess virulence genes and 83% were in the phylogenetic group A. Results of this study indicated that E. coli with R1, R2, R3 and R4 were important in causing infections in chickens and further, the E. coli with R4 core type were less common among commensals, possessed more virulence genes and were related to phylogenetic groups pathogenic for poultry. 相似文献
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Objective To assess the innate resistance of naive Bos taurus, Bos taurus cross Bos indicus and Bos indicus cattle to virulent Babesia bovis, B bigemina and Anaplasma marginale parasites. Design Groups of 10, pure B indicus, fi B indicus cross,/B indicus cross and pure B taurus steers were infected with virulent B bovis, B bigemina and A marginale parasites. Procedure Sequential infections were carried out by intravenous inoculation of infected blood containing 1 times 108 parasites of B bovis, followed by B bigemina and then A marginale. To assess resistance, measurements were made of parasitaemia, rectal temperature, packed cell volume and the number within a group requiring chemotherapy to control infection. There was a recovery period between each infection. Results Infection with B bovis showed that pure B indicus steers were significantly more resistant to B bovis infection than the other groups, with none of this group requiring treatment. There was no significant difference between fi B indicus cross and/B indicus cross with 30% and 20%, respectively, of steers in these groups requiring treatment. The pure B taurus steers were significantly more affected then those in the other three groups with 80% requiring treatment. Infections of B bigemina produced a mild response in comparison to that of B bovis and none of the steers required treatment. However, the pure B taurus group was significantly more affected than the other three groups for all other measurements. After the A marginale infection, B indicus steers were moderately affected with 50% requiring treatment, whereas 70% of the fi B indicus group, 80% of the /B indicus cross group and 100% of the pure B taurus group required treatment. Conclusions All breeds of cattle, ranging from pure B indicus to pure B taurus may be at risk of severe disease if exposed to virulent A marginale. The results confirm that pure B indicus cattle are relatively resistant to B bovis, but there could be a significant risk of severe mortalities if cross-bred herds are exposed to virulent infection. 相似文献