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71.
Ana Afonso Jose Cortinas Abrahantes Franz Conraths Anouk Veldhuis Armin Elbers Helen Roberts Yves Van der Stede Estelle Méroc Kristel Gache Jane Richardson 《Preventive veterinary medicine》2014
During the Schmallenberg virus (SBV) epidemic, the European Food Safety Authority (EFSA) collected data on SBV occurrence across Europe in order to provide an assessment of spread and impact. By May 2013, twenty-nine countries were reporting to EFSA and twenty-two countries had reported cases of SBV. The total number of SBV herds reported was 13,846 and the number of SBV laboratory confirmed herds was 8730. The surveillance activities were based on the detection of SBV clinical cases (either adults or newborns). Malformation in newborns was the most commonly reported clinical sign of SBV-infection. All countries were able to provide the date when the first suspicion of SBV in the herd was reported and nineteen could report the location of the herd at a regional level. This allowed the spread of SBV in Europe to be measured both temporally and spatially. The number of SBV confirmed herds started to increase in December 2011 and two peaks were observed in 2012 (February and May). Confirmed herds continued to be reported in 2012 and into 2013. An increase during winter 2012 and spring 2013 was again observed, but the number of confirmed herds was lower than in the previous year. SBV spread rapidly throughout Europe from the initial area of detection. SBV was detected above the latitude of 60° North, which exceeds the northern expansion observed during the bluetongue virus serotype 8 epidemic in 2006–2009. The impact of SBV was calculated as ratio of the number of herds with at least one malformed SBV positive foetus and the total number of herds in this region. The 75th percentile of the malformations ratio in the various affected countries for the whole reporting period was below 1% and 3% for cattle and sheep herds, respectively. International data collection on emerging diseases represents a challenge as the nature of available data, data quality and the proportion of reported cases may vary widely between affected countries. Surveillance activities on emerging animal diseases are often structured only for case detection making the estimation of infection/diseases prevalence and the investigation of risk factors difficult. The impact of the disease must be determined to allow risk managers to take appropriate decisions. Simple within-herd impact indicators suitable for emerging disease outbreaks should be defined that could be measured as part of routine animal health surveillance programmes and allow for rapid and reliable impact assessment of emerging animal health diseases. 相似文献
72.
The current treatment for amoebic gill disease (AGD)-affected Atlantic salmon involves bathing sea-caged fish in fresh water, often sourced from local dams, for 3-4 h. In both a small-scale laboratory and an on-farm field experiment, the effects of water hardness on the efficacy of freshwater bathing were assessed. Results showed that soft fresh water (19.3-37.4 mg L(-1) CaCO3), whether it be naturally soft city mains water or artificially softened dam water, was more efficacious at alleviating AGD in affected fish than hard fresh water (173-236.3 mg L(-1) CaCO3). Soft freshwater bathing significantly reduced viable gill amoebae numbers (from 73.9 to 40.9% of total count) and significantly alleviated gill pathology, both gross and histological. Following bathing, gross gill pathological scores of soft freshwater bathed fish lagged 2 weeks behind hard freshwater bathed fish. Significant gill lesion fragmentation, and shedding of lesion-associated hyperplastic tissue, was accompanied by a significant reduction in AGD-affected gill filaments in soft freshwater bathed fish. Furthermore, soft freshwater bathing alleviated the blood plasma electrolyte imbalance seen in control (sea water) and hard freshwater bathed fish. This study showed that the use of soft fresh water for bathing AGD-affected Atlantic salmon could be an improvement to the current method of treatment. Not only does it reduce gill amoeba numbers, but also, it is of a therapeutic advantage with the potential to reduce bathing frequency. 相似文献
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Pathogenicity and cultural experiments described here provide futher evidence that a distinct species of Aphanomyces is responsible for much of the characteristic pathology of epizootic ulceration syndrome (EUS). Zoospores from 58 fungal isolates were injected intramuscularly in snakehead fish, Channa striata (Bloch). These fungi comprised: Aphanomyces strains isolated from EUS-affected fish; saprophytic Aphanomyces , Achlya and Saprolegnia spp. from infected waters; and further saprolegniaceous fungi involved in other diseases of aquatic animals. Only the Aphanomyces strains isolated from fish affected by EUS, Australian red spot disease (already considered synonymous with EUS) or mycotic granulomatosis described from Japan were able to grow invasively through the fish muscle and produce the distinctive EUS lesions. In contrast to Aphanomyces astaci Schikora, the EUS- Aphanomyces was shown to be unable to infect noble crayfish, Astacus astacus L. The snakehead-pathogenic strains were further distinguished from all the other fungi under comparison by their characteristic temperature-growth profile and inability to grow on certain selective fungal media. 相似文献
76.
Andrea Sáenz–Arroyo Callum M. Roberts Jorge Torre & Micheline Cariño-Olvera 《Fish and Fisheries》2005,6(2):121-133
Designing fishing policies without knowledge of past levels of target species abundance is a dangerous omission for fisheries management. However, as fisheries monitoring started long after exploitation of many species began, this is a difficult issue to address. Here we show how the ‘shifting baseline’ syndrome can affect the stock assessment of a vulnerable species by masking real population trends and thereby put marine animals at serious risk. Current fishery data suggest that landings of the large Gulf grouper (Mycteroperca jordani, Serranidae) are increasing in the Gulf of California. However, reviews of historical evidence, naturalists’ observations and a systematic documentation of fishers’ perceptions of trends in the abundance of this species indicate that it has dramatically declined. The heyday for the Gulf grouper fishery occurred prior to the 1970s, after which abundance dropped rapidly, probably falling to a few percent of former numbers. This decline happened long before fishery statistics were formally developed. We use the case of the Gulf grouper to illustrate how other vulnerable tropical and semi‐tropical fish and shellfish species around the world may be facing the same fate as the Gulf grouper. In accordance with other recent studies, we recommend using historical tools as part of a broad data‐gathering approach to assess the conservation status of marine species that are vulnerable to over‐exploitation. 相似文献
77.
Dan Laffoley John M. Baxter Diva J. Amon Duncan E.J. Currie Craig A. Downs Jason M. Hall‐Spencer Harriet Harden‐Davies Richard Page Chris P. Reid Callum M. Roberts Alex Rogers Thorsten Thiele Charles R.C. Sheppard Rashid U. Sumaila Lucy C. Woodall 《水产资源保护:海洋与淡水生态系统》2020,30(1):194-208
- The ocean crisis is urgent and central to human wellbeing and life on Earth; past and current activities are damaging the planet's main life support system for future generations. We are witnessing an increase in ocean heat, disturbance, acidification, bio‐invasions and nutrients, and reducing oxygen levels. Several of these act like ratchets: once detrimental or negative changes have occurred, they may lock in place and may not be reversible, especially at gross ecological and ocean process scales.
- Each change may represent a loss to humanity of resources, ecosystem function, oxygen production and species. The longer we pursue unsuitable actions, the more we close the path to recovery and better ocean health and greater benefits for humanity in the future.
- We stand at a critical juncture and have identified eight priority issues that need to be addressed in unison to help avert a potential ecological disaster in the global ocean. They form a purposely ambitious agenda for global governance and are aimed at informing decision‐makers at a high level. They should also be of interest to the general public.
- Of all the themes, the highest priority is to rigorously address global warming and limit surface temperature rise to 1.5°C by 2100, as warming is the pre‐eminent factor driving change in the ocean. The other themes are establishing a robust and comprehensive High Seas Treaty, enforcing existing standards for Marine Protected Areas and expanding their coverage, especially in terms of high levels of protection, adopting a precautionary pause on deep‐sea mining, ending overfishing and destructive fishing practices, radically reducing marine pollution, putting in place a financing mechanism for ocean management and protection, and lastly, scaling up science/data gathering and facilitating data sharing.
- By implementing all eight measures in unison, as a coordinated strategy, we can build resilience to climate change, help sustain fisheries productivity, particularly for low‐income countries dependent on fisheries, protect coasts (e.g. via soft‐engineering/habitat‐based approaches), promote mitigation (e.g. carbon storage) and enable improved adaptation to rapid global change.
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Abstract – The links between river flows, water temperature, river regulation and recruitment variability of Golden Perch, Macquaria ambigua oriens, were investigated from the Fitzroy Basin, Queensland. The dominant age classes determined by interpreting growth marks observed in otoliths were variable among rivers. Positive correlations between the age frequency and monthly river flow volumes were greatest in summer (December–March) conversely, autumn, winter and spring river flows correlated poorly for most rivers. Water temperature exhibits strong seasonality across the basin with mean monthly temperatures >23 °C generally occurring between October and April. These data indicate the combination of water temperature and increased river flows are important factors for recruitment. The degree of river regulation is also suspected of contributing to increased variability in dominant age classes within rivers. This assessment highlights the importance of timing of river flows in mitigating the negative effects of river regulation on golden perch populations. 相似文献
80.
Feeding and digestive problems in horses. Physiologic responses to a concentrated meal 总被引:2,自引:0,他引:2
L L Clarke M C Roberts R A Argenzio 《Veterinary Clinics of North America: Equine Practice》1990,6(2):433-450
The association of feeding practices with the development of digestive disorders in horses has long been recognized, although the underlying mechanisms had been barely considered. The physiologic consequences of meal frequency may help to explain the relationship and prove to be of major significance in the induction of many conditions. Many Equidae kept for performance and leisure activities are fed high-energy, low-forage rations twice daily, with limited access to hay or grazing. Rapid ingestion of such meals stimulates a copious outpouring of upper alimentary secretions and results in transient hypovolemia (15% plasma volume loss). Subsequent activation of the renin-angiotensin-aldosterone system (RAAS) contributes to the preservation of circulatory status. Large meals may accelerate digesta passage to the cecum and, thereby, increase soluble carbohydrate availability for large intestinal fermentation. Intense periods of fermentation develop that require significant shifts of fluid into the colonic lumen. This is followed by net fluid absorption, which, in part, is dependent on postprandial increases of aldosterone. Potential consequences of these events include (1) imbalances in the RAAS response, which may promote conditions favorable to gastrointestinal disturbance, notably large intestinal impaction, and (2) changes in the gastrointestinal microflora, which may affect the intraluminal endotoxin pool and the population of enterotoxin-producing bacteria. In contrast to episodic feedings, similar changes are absent or greatly attenuated under simulated grazing conditions (for example, small, frequent meals). Thus, modification of management practices to facilitate a more continuous feeding pattern may significantly reduce the incidence of digestive problems in the stabled horse. 相似文献