Application of high-resolution melt curve analysis for classification of infectious bronchitis viruses in field specimens

Objective A real-time polymerase chain reaction (PCR)/high-resolution melt (HRM) curve analysis protocol was developed in our laboratory to differentiate infectious bronchitis (IB) virus reference strains. In the current study, this method was used to detect and classify IB viruses in field submissions. Procedure Over an 11-month period samples from 40 cases of suspected IB virus were received and 17 submissions were positive for IB virus by polymerase chain reaction. HRM curve analysis classified each strain as subgroup 1, 2 or 3 strain (12 submissions) or a strain that was unable to be classified (5 submissions). The 3′ untranslated region (UTR) and partial S1 gene nucleotide sequences for the 17 IB virus strains were determined and their identity with those of the relative reference strains compared to confirm the classifications generated using the HRM curve analysis. Results Of the 12 IB field viruses classified as subgroup 1, 2, or 3 using HRM curve analysis, the 3′UTR and S1 gene nucleotide sequences had identities ≥99% with the respective subgroup reference strain. Analysis of the 3′ UTR and S1 gene nucleotide sequences for the five IB virus strains that could not be classified indicated that four belonged to one of the subgroups, and one was a potential recombinant strain (between strains from subgroups 2 and 3). A novel recombinant strain was also detected. Conclusion HRM curve analysis can rapidly assign the majority of IB viruses present in field submissions to known subgroups. Importantly, HRM curve analysis also identified variant genotypes that require further investigation.     

新疆褐牛导入美国瑞士褐牛后代犊牛放牧补饲试验

[目的]研究新疆褐牛导入杂交后代在不同生产方式下的生产性能与适应性.[方法]选择美新褐杂交F1代、F2代犊牛68头,并按品种类型、性别随机分为2组,试验组为放牧补饲生产,对照组为天然放牧生产.[结果]表明:美新褐牛F1代、F2代犊牛试验组与对照组相比日增重显著(P＜0.05),试验组F1代较F2代公牛日增重提高10％,...     

The use of concentrated bovine serum albumin in canines.

In humans it has been estimated that for each 2.5 g L^–1 decrease in serum albumin, risk of death increases by 24–56%. Clinical impression suggests this may be similar in veterinary patients. Species‐specific albumin (plasma) is often unavailable and concentrated solutions are not. Our experience using 25% human serum albumin (HSA) in critically ill dogs suggests a positive effect (results submitted), however it is expensive. Bovine serum albumin (BSA) may be a more cost effective and readily available alternative. The purpose of this study was to assess the immediate and long‐term safety of an intravenous dose (500 mg kg^–1) of bovine albumin administered to healthy dogs. Ten mature dogs (eight males, two females, 28 ± 6 kg) were to receive BSA (250 mg mL^–1) twice (BSA1 and BSA2) with 14 days between treatments. Temperature, blood pressure, and pulse and respiration rate were continuously monitored to identify a reaction to BSA. All dogs received BSA1. One dog immediately developed mild urticaria and pruritus, otherwise the infusion was well tolerated. No immediate reaction was noted in the other nine dogs. Two dogs received BSA2. One dog developed a mild immediate reaction similar to that occurring with BSA1, and one dog (the dog immediately reacting to BSA1) developed a severe anaphylactic reaction. Due to these reactions, no other dogs received BSA2. During a two‐week observation of the remaining eight dogs given BSA1, five developed a mild or severe generalized type‐III hypersensitivity reaction. The dog experiencing a mild reaction during BSA2 administration also developed a generalized type‐III hypersensitivity reaction. Delayed reactions occurred 15 ± 2.7 days after BSA exposure. Three dogs did not develop a reaction. All reacting dogs recovered fully. The severity of reactions, and the number of dogs affected, suggests prior (natural) exposure and immunological sensitization to bovine albumin. Bovine serum albumin is not suitable for therapeutic use in dogs.     

试管苗简化培养试验初探

通过简化培养基成分,去除有机物,可抑制在长期继代培养中被茵类污染的试管苗;采用液体培养,可降低试管苗成本;用自然光代替日光灯,并结合黑暗培养,可减少设备投入,简化培养室条件,有利于工厂化育苗生产.     

Spina bifida with associated malformations of the central nervous system in Dorper-cross sheep

Abstract

CASE HISTORY: In 2008, six lambs within a flock of Dorpercross sheep were born with musculoskeletal and neurological disease. Clinical signs included hindlimb weakness, and urinary incontinence.

CLINICAL FINDINGS: All lambs had focal, inverted areas of alopecic skin over the caudal sacrum, and short, often kinked tails. Four affected lambs were subject to euthanasia, and necropsied. On gross examination, the arches of sacral vertebrae were absent, and spinal nerves and meninges were adherent to the overlying subcutis. Other gross lesions included narrow, elongated skulls, herniation of the occipital lobes into the caudal fossas, hydrocephalus, and syringomyelia. One lamb had coning of the cerebellar vermis, but cerebellar herniation through the foramen magnum was not identified.

DIAGNOSIS: Spina bifida, with associated malformations of the central nervous system.

CLINICAL RELEVANCE: Examination of breeding records suggested either an autosomal recessive or partially penetrant autosomal dominant pattern of inheritance. Because of the associated tail lesions it is proposed that the pathogenesis of this syndrome involves a defect in development of the tail bud (secondary neurulation), that tethering of the spinal cord resulted in the clinical signs, and abnormal pressure of the cerebral spinal fluid resulted in the defects in the skull and brain.     

Decision support systems for monitoring and maintaining health in food animal populations

To mitigate the effects of risks to food safety and infectious disease outbreaks in farmed animals, animal health authorities need to have systems in place to identify and trace the source of identified problems in a timely manner. In the event of emergencies, these systems will allow infected or contaminated premises (and/or animals) to be identified and contained, and will allow the extent of problems to be communicated to consumers and trading partners in a clear and unambiguous manner. The key to achieving these goals is the presence of an effective animal health decision support system that will provide the facilities to record and store detailed information about cases and the population at risk, allowing information to be reported back to decision makers when it is required. Described here are the components of an animal health decision support system, and the ways these components can be used to enhance food safety, responses to infectious disease incursions, and animal health and productivity. Examples are provided to illustrate the benefit these systems can return, using data derived from countries that have such systems (or parts of systems) in place. Emphasis is placed on the features that make particular system components effective, and strategies to ensure that these are kept up to date.     

Knowledge and attitudes of Australian livestock producers concerning biosecurity practices

Biosecurity risks are a major threat to the profitability of the industry as well as impacting human and animal health. Livestock producers play a crucial role in biosecurity as the first to notice changes in the health or productivity of their stock and are generally responsible for implementing protective measures. However, uptake of biosecurity measures by producers is variable. We critically appraised the current literature regarding biosecurity practices in Australian livestock industries and highlight aspects that are well understood as well as those where further research or information is needed. Findings from 12 cross-sectional studies suggest that Australian producers' knowledge of biosecurity methods and importance might have a positive influence on their willingness to implement or incorporate biosecurity practices. There is moderate evidence supportive of biosecurity being well understood by livestock producers across Australia. Barriers to producers using biosecurity practices included lack of information or communication from agricultural, veterinary or government organisations. It was found that larger stock numbers were positively correlated with biosecurity implementation and that producers used veterinarians, government and industry agencies as resources for trusted information.     

Long-term development of fish populations in the Římov Reservoir

Abstract  The inshore fish community of the Římov Reservoir in the Czech Republic was evaluated over 21 years using shore seining at night. The development of the fish community was divided into two separate phases: a highly dynamic and unstable phase dominated by perch, Perca fluviatilis L., was replaced by an extremely stable cyprinid phase dominated by roach, Rutilus rutilus (L.), and bream, Abramis brama (L.). The abundance of both these species oscillated during the cyprinid phase, but with decreasing amplitude. The proportion of piscivorous fish species such as asp, Aspius aspius (L.), pike, Esox lucius L., and pikeperch, Sander lucioperca (L.), increased slightly with time but remained low. The biomass of large Cladocera was negatively correlated with fish biomass only during the perch phase. The Shannon–Weaver index of diversity increased during the fish community succession, mainly because of greater evenness amongst the species.     

Environmental effects on forage and longline fishery performance for albacore (Thunnus alalunga) in the American Samoa Exclusive Economic Zone

The South Equatorial Counter Current (SECC) strongly influences the American Samoa Exclusive Economic Zone (EEZ) and changes strength on a seasonal and ENSO cycle. A strong SECC is associated with a predominantly anticyclonic eddy field as well as increased micronekton biomass and catch-per-unit-effort (CPUE) for albacore tuna, the economically important target species of the local longline fishery. A strong SECC carries chlorophyll a -rich waters from upwelling regions at the north coast of New Guinea towards the EEZ, most likely resulting in the observed increase in micronekton biomass, forage for albacore. Relatively stable anticyclonic eddies show a further increase in micronekton biomass, apparently advected from neighboring SECC waters. The presence of forage presumably concentrates albacore, thus resulting in the observed increase in CPUE. High shear regions of neither anticyclonic nor cyclonic eddies correlate with increased micronekton biomass. Areas characterized by South Equatorial Current (SEC) waters correspond to areas with the lowest micronekton biomass and the highest number of aggregative structures, which are most likely small pelagic fish shoals. Micronekton composition in SEC waters differs from that in the SECC. During El Niños, the seasonal signals at the north shore of New Guinea and in the SECC are exceptionally strong and correspond to higher albacore CPUE in the EEZ. My results suggest that the strength of upwelling and the resulting increase in chlorophyll a at New Guinea, as well as the Southern Oscillation Index, could be used to predict the performance of the local longline fishery for albacore tuna in the American Samoa EEZ.     

不同施肥时间及施氮水平对高寒草甸生物量和土壤养分的影响

采用随机区组设计,探讨了不同施肥时期及氮肥用量对三江源区高寒草甸初级生产力、植物养分及土壤养分的影响。结果表明:在施肥时间为7月10日,施肥量为150 kg·hm^-2时,地上生物量为最大值,较对照增加了2.06倍(P <0.05)。而植物氮素含量在施肥时间为7月10日,尿素用量为300 kg·hm^-2时达到最大值,较对照增加了31.18%(P <0.05)。相关性分析表明,地上生物量与植物全氮成显著正相关,施氮量与植物全氮成线性相关。施肥时间为7月10日左右时,尿素施用水平为150~300 kg·hm^-2,该类型高寒草甸初级生产力和土壤全氮都达到最大值,可作为优先氮素添加量来推荐。