Investigation of mortality in Pacific oysters associated with Ostreid herpesvirus-1 μVar in the Republic of Ireland in 2009

High levels of mortality in Pacific oysters Crassostrea gigas in the Republic of Ireland were recorded during the summer of 2009. The new variant of Ostreid herpes 1 (OsHV-1 μVar) which first emerged in France in 2008 was identified from affected stocks. Retrospective data was collected from 70 oyster farmers through an interviewer-administered questionnaire to investigate the distribution and determinants of the mortality. Based on farmer recall, data were recorded at the batch level for cumulative mortality during 2009, start dates and duration of the mortality event and the age of animals affected. Observable mortalities were recorded in 109 out of 346 batches at 47 sites; 104 of the 109 batches were located in bays where OsHV-1 μVar had been detected. The records from bays where OsHV-1 μVar had been detected were analysed to characterize the pattern of mortality and potential risk factors. Batch mortality averaged 37% (18-65% quartiles) but showed a bimodal distribution (half the batches had mortality less than 45%). Mortalities started at the end of May and continued until early August, peaking in early July. On average oysters died over a period of 18 days. Mortality varied considerably both between and within bays. Mortality started in recently introduced batches and occurred later in the summer in established oysters, which is consistent with the introduction of an infectious agent. Mortality was significantly lower in adults compared with other age groups, which supports observations from France. Three variables were significantly (P<0.05) associated, in both bivariate screening and a logistic regression, with high batch-level mortality (>40%): oysters (i) introduced as juveniles, (ii) during or since the winter of 2008/9 and (iii) which spent less than 8h out of water (in a tidal cycle) (compared with oysters introduced as adults before the winter of 2008/9 and spending more than 8h out of water). Twenty-one percent of triploid batches experienced "high" (>40%) mortality compared with 10% for diploid batches which was significant (P<0.05) in the initial bivariate screening but not in the final logistic regression model. Future studies should develop improved methods to assess oyster mortality and follow stocks over time to better determine the influence of management and environmental factors on mortality.     

Molecular analyses of disease pathogenesis: application of bovine microarrays

The molecular analysis of disease pathogenesis in cattle has been limited by the lack of availability of tools to analyze both host and pathogen responses. These limitations are disappearing with the advent of methodologies such as microarrays that facilitate rapid characterization of global gene expression at the level of individual cells and tissues. The present review focuses on the use of microarray technologies to investigate the functional pathogenomics of infectious disease in cattle. We discuss a number of unique issues that must be addressed when designing both in vitro and in vivo model systems to analyze host responses to a specific pathogen. Furthermore, comparative functional genomic strategies are discussed that can be used to address questions regarding host responses that are either common to a variety of pathogens or unique to individual pathogens. These strategies can also be applied to investigations of cell signaling pathways and the analyses of innate immune responses. Microarray analyses of both host and pathogen responses hold substantial promise for the generation of databases that can be used in the future to address a wide variety of questions. A critical component limiting these comparative analyses will be the quality of the databases and the complete functional annotation of the bovine genome. These limitations are discussed with an indication of future developments that will accelerate the validation of data generated when completing a molecular characterization of disease pathogenesis in cattle.     

Update on the development of a novel dry cow therapy using a bismuth-based intramammary teat seal in combination with the bacteriocin lacticin 3147

: Public concerns over the widespread prophylactic use of antibiotics have led to a search for alternatives to dry cow therapy for the prevention of intramammary infections. A popular alternative is to infuse a teat seal at drying-off. The teat seal is a viscous non-antibiotic formulation and when it is infused into the teat canal and the teat sinus it forms an internal seal that provides a physical barrier to invasion by mastitis-causing pathogens. Enhancement of teat seal formulations may be achieved using non-antibiotic additives such as bacteriocins, potent proteins produced by some bacteria that have the ability to kill other microorganisms. This paper traces the history of investigations at Moorepark Research Centre into the efficacy of teat seal plus lacticin 3147, a bacteriocin produced by Lactococcus lactis DPC3147, in the prevention of intramammary infections in dry cows. Indications from on-going investigations are that a dry cow formulation combining the two products has considerable potential as a non-antibiotic prophylactic product.     

Cardiac effects of pulmonary disease.

Pulmonary hypertension (PHT) is the primary cardiac consequence of pulmonary disease. It develops as alveolar hypoxia of pulmonary disease, coupled with vasoactive and mitogenic substances released from pulmonary endothelial and vascular smooth muscle cells damaged by the primary disease process, mediates arterial vasoconstriction and vascular remodeling to raise pulmonary vascular resistance. Independent of the underlying pulmonary disease, PHT produces clinical signs of respiratory distress, exercise intolerance, syncope, and right heart failure. Diagnosis of PHT is made by estimation of pulmonary artery pressures by means of continuous-wave Doppler echocardiographic assessment of tricuspid or pulmonic regurgitant flow velocity. Treatment of PHT is directed at the underlying pulmonary disease but may also aim to attenuate pulmonary artery pressure and limit the clinical sequelae of PHT. No treatments are of proven benefit in veterinary patients; irrespective of the nature of the inciting pulmonary disease, the prognosis is often grave.     

Influence of N-, P- and Si-based Flame Retardant Mixtures on Flammability,Thermal Behavior and Mechanical Properties of PA6 Composite Fibers

This research investigated the influence of two flame retardant (FR) mixtures consisting melamine cyanurate (MeCy) and aluminum diethylphosphinate (AlPi), and MeCy and sodium aluminosilicate (SASi) at different weight ratios, on the flammability, thermal behavior and mechanical properties of polyamide 6 (PA6) composite yarns produced by meltspinning. The morphological and chemical properties of PA6/FR filaments were investigated by scanning electron microscopy and Fourier-transform infrared spectroscopy, flame retardancy by vertical burning test UL-94, thermal behavior by thermogravimetric and differential scanning calorimetric analyses, and mechanical properties by tensile tests. The results indicate that within the UL 94 V2 rating, the composite yarns differed significantly from each other in their burning and dripping behavior. The incorporation of both mixtures, MeCy+AlPi and MeCy+SASi, into the PA6/FR yarns significantly decreased the afterflame time relative to pristine PA6, confirming a lower production of flammable volatiles. This phenomenon was attributed mainly to MeCy, which caused an immediate extinguishment of the flame after the withdrawal of the igniting flame. Compared to one component MeCy, the incorporation of the MeCy+SASi mixture enhanced the thermooxidative stability of the PA6/FR yarns because of their additive effect at higher concentrations. In contrast, an antagonistic effect was obtained for the MeCy+AlPi mixture, irrespective of the concentration. Since the incorporation of MeCy+SASi did not drastically reduce the tensile properties of filaments, this mixture enables the production of the PA6/MeCy+SASi composite yarns with the enhanced flame retardancy and thermo-oxidative stability.     

An optimised protocol for molecular identification of Eimeria from chickens

Molecular approaches supporting identification of Eimeria parasites infecting chickens have been available for more than 20 years, although they have largely failed to replace traditional measures such as microscopy and pathology. Limitations of microscopy-led diagnostics, including a requirement for specialist parasitological expertise and low sample throughput, are yet to be outweighed by the difficulties associated with accessing genomic DNA from environmental Eimeria samples. A key step towards the use of Eimeria species-specific PCR as a sensitive and reproducible discriminatory tool for use in the field is the production of a standardised protocol that includes sample collection and DNA template preparation, as well as primer selection from the numerous PCR assays now published. Such a protocol will facilitate development of valuable epidemiological datasets which may be easily compared between studies and laboratories. The outcome of an optimisation process undertaken in laboratories in India and the UK is described here, identifying four steps. First, samples were collected into a 2% (w/v) potassium dichromate solution. Second, oocysts were enriched by flotation in saturated saline. Third, genomic DNA was extracted using a QIAamp DNA Stool mini kit protocol including a mechanical homogenisation step. Finally, nested PCR was carried out using previously published primers targeting the internal transcribed spacer region 1 (ITS-1). Alternative methods tested included sample processing in the presence of faecal material, DNA extraction using a traditional phenol/chloroform protocol, the use of SCAR multiplex PCR (one tube and two tube versions) and speciation using the morphometric tool COCCIMORPH for the first time with field samples.     

Nudging fisheries and aquaculture research towards food systems

Food system is a powerful concept for understanding and responding to nutrition and sustainability challenges. Food systems integrate social, economic, environmental and health aspects of food production through to consumption. Aquatic foods are an essential part of food systems providing an accessible source of nutrition for millions of people. Yet, it is unclear to what degree research across diverse disciplines concerning aquatic foods has engaged food systems, and the value this concept has added. We conducted a systematic review of fisheries, aquaculture and aquatic food literature (2017–2019) to determine the following: the characteristics of this research; the food systems components and interrelations with which research engaged; and the insights generated on nutrition, justice, sustainability and climate change. Sixty five of the 88 reviewed articles focussed on production and supply chains, with 23 considering human nutrition. Only 13% of studies examined low- and middle-income countries that are most vulnerable to undernutrition. One third of articles looked beyond finfish to other aquatic foods, which illuminated values of local knowledge systems and diverse foods for nutrition. When aggregated, reviewed articles examined the full range of food system drivers—biophysical and environmental (34%), demographic (24%) and socio-cultural (27%)—but rarely examined interactions between drivers. Future research that examines a diversity of species in diets, system-wide flows of nutrients, trade-offs amongst objectives, and the nutritional needs of vulnerable social groups would be nudging closer to the ambitions of the food systems concept, which is necessary to address the global challenges of equity, nutrition and sustainability.