Screening for Rift Valley fever infection in northern Somalia: a GIS based survey method to overcome the lack of sampling frame     

Soumare B  Tempia S  Cagnolati V  Mohamoud A  Van Huylenbroeck G  Berkvens D 《Veterinary microbiology》2007,121(3-4):249-256

Following repeated import bans imposed by Saudi Arabia on livestock originated from Somalia due to suspicion of Rift Valley fever (RVF) presence and the severe socio-economic consequences of this, it was imperative for the Somaliland government to carry out surveillance activities in order to determine the status of transboundary diseases in its territory. A GIS computer software (Arcview) was used to overcome the lack of lists of sampling sites due to the high mobility of pastoral nomadic herds in the study area. This method proved very convenient and flexible for the random selection of sampling sites and thus the compliance with the requirements by the World Organisation for Animal Health (OIE) for statistically valid methods if the surveillance outcome is to meet international recognition and acceptance. Screening in Somaliland in 2001 and in Puntland in 2003 which targeted mainly sheep and goats aged 1-2 years (97% of surveyed animals) revealed no signs compatible with the disease but an overall sero-prevalence of 2+/-0.02% (90/4570) and 5+/-0.3% (206/4050), respectively. The spatial distribution showed clusters of high sero-prevalence located mostly in the Nugal Valley. This trend was confirmed by the follow-up survey implemented in Somaliland in 2004 with a herd prevalence of 80+/-6% and a within-herd prevalence up to 50% located again in the Nugal Valley. This result suggests the maintenance and increase of RVF virus activity in the valley. In addition conditions favourable to the breeding and survival of the vector population and the high density of livestock make the Nugal Valley an area of high risk for a RVF outbreak where sentinel herds will be placed.  相似文献   

Bayes and diagnostic testing     

Lesaffre E  Speybroeck N  Berkvens D 《Veterinary parasitology》2007,148(1):58-61

Interpretation of the result of a diagnostic test depends not only on the actual test result(s) but also on information external to this result, namely the test's sensitivity and specificity. This external information (also called prior information) must be combined with the data to yield the so-called updated, posterior estimates of the true prevalence and the test characteristics. The Bayesian approach offers a natural, intuitive framework in which to carry out this estimation process. The influence of the prior information on the final result may not be ignored. Guidance for the choice of prior information not in conflict with the data can be obtained from a set of statistics and indices (DIC, p(D), Bayes-p).  相似文献   

Role of sugars in surface microbe-host interactions and immune reaction modulation     

Lloyd DH  Viac J  Werling D  Rème CA  Gatto H 《Veterinary dermatology》2007,18(4):197-204

Sugars in the form of monosaccharides, oligosaccharides, polysaccharides and glycoconjugates (glycoproteins, glycolipids) are vital components of infecting microbes and host cells, and are involved in cell signalling associated with modulation of inflammation in all integumental structures. Indeed, sugars are the molecules most commonly involved in cell recognition and communication. In skin, they are essential to epidermal development and homeostasis. They play important roles in microbial adherence, colonization and biofilm formation, and in virulence. Two groups of pathogen recognition receptors, C-type lectins (CTL) and their receptors (CTLR), and the Toll-like receptors enable the host to recognize pathogen-associated molecular patterns (PAMPs), which are mainly glycolipids. The CTLs can recognize a wide variety of bacteria, fungi and parasites and are important in phagocytosis and endocytosis. TLRs are expressed on the surfaces of a variety of cells, including keratinocytes, dendritic cells, monocytes and macrophages; they play a major role in innate immunity. Interaction of TLRs with PAMPs initiates a cascade of events leading to production of reactive oxygen intermediates, cytokines and chemokines, and promotes inflammation. Exogenous sugars can block carbohydrate receptors and competitively displace bacteria from attachment to cells, including keratinocytes. Thus sugars may provide valuable adjunctive anti-inflammatory and/or antimicrobial treatment. A promising approach is the use of a panel of carbohydrate derivatives with anti-adhesive efficacy against bacteria frequently involved in diseases affecting skin and other epithelia. More complete characterization of sugar receptors and their ligands will provide further keys to use of carbohydrates in immunomodulation and infection control in skin.  相似文献   

Pattern recognition receptors in companion and farm animals - the key to unlocking the door to animal disease?     

Werling D  Coffey TJ 《Veterinary journal (London, England : 1997)》2007,174(2):240-251

The innate immune system is essential for host defence and is responsible for early detection of potentially pathogenic microorganisms. Upon recognition of microbes by innate immune cells, such as macrophages and dendritic cells, diverse signalling pathways are activated that combine to define inflammatory responses that direct sterilisation of the threat and/or orchestrate development of the adaptive immune response. Innate immune signalling must be carefully controlled and regulation comes in part from interactions between activating and inhibiting signalling receptors. In recent years, an increasing number of pattern recognition receptors (PRRs), including C-type lectin receptors and Toll-like receptors (TLRs), has been described that participate in innate recognition of microbes, especially through the so called pathogen-associated molecular patterns (PAMPs). Recent studies demonstrate strong interactions between signalling through these receptors. Whereas useful models to study these receptors in great detail in the murine and human system are now emerging, relatively little is known regarding these receptors in companion and farm animals. In this review, current knowledge regarding these receptors in species of veterinary relevance is summarised.  相似文献   

Langzeitwirkungen von Astungen im Holz von Linde und Roßkastanie     

Dirk Dujesiefken  Horst Stobbe  Dieter Eckstein 《European Journal of Forest Research》1998,117(1-6):305-315

  相似文献   

Twin pregnancies following transfer of single embryos in three mares: A case report     

Patrick M. McCue DVM  PhD  Jill Thayer DVM  Edward L. Squires PhD  Steven P. Brinsko DVM  PhD  Dirk K. Vanderwall DVM  PhD 《Journal of Equine Veterinary Science》1998,18(12):832-834

Spontaneous development of identical or monozygotic twins is a rare event in the horse. Monozygotic twins develop after division of a single embryo. This report documents three cases in which twin embryos developed following surgical transfer of a single morula stage embryo into the uterus of a synchronized recipient mare.  相似文献   

Mercury Bioaccumulation in Rainbow Trout (Oncorhynchus mykiss) and the Trout Food Web in Lakes Okareka,Okaro, Tarawera,Rotomahana and Rotorua,New Zealand     

Kim  Jonathan P.  Burggraaf  Shane 《Water, air, and soil pollution》1999,115(1-4):535-546

Methyl mercury (Hg) was determined in rainbow trout (Oncorhynchus mykiss) and organisms in the lower tropic levels: smelts (Retropinna retropinna), bullies (Gobiomorphus cotidianus), koura (Paranephrops planifrons); and zooplankton (Daphnia carinata and Calamoecia lucasi) in Lakes Okareka, Okaro, Tarawera, Rotorua and Rotomahana, New Zealand. Water concentrations of total Hg (Hg_T) and methyl Hg were also measured. Mean methyl Hg concentrations in the trout, the prey species (smelts, bullies and koura) and zooplankton increased linearly with mean Hg_T and methyl Hg chloride (CH₃HgCl) concentrations in water. Most of the bio-magnification of methyl Hg occurred in the lower trophic levels of the trout food web (10^4.72) between the zooplankton and water. The bioaccumulation factors between the forage fish and zooplankton were 10^0.73 for bullies and 10^1.06 for smelt. Methyl Hg was 10^0.41 to 10^0.95 times greater in the trout then their prey.  相似文献   

Progress and challenges in freshwater conservation planning     

Jeanne L. Nel  Dirk J. Roux  Robin Abell  Peter J. Ashton  Richard M. Cowling  Jonathan V. Higgins  Michele Thieme  Joshua H. Viers 《水产资源保护:海洋与淡水生态系统》2009,19(4):474-485

• 1. Freshwater ecosystems and their associated biota are among the most endangered in the world. This, combined with escalating human pressure on water resources, demands that urgent measures be taken to conserve freshwater ecosystems and the services they provide. Systematic conservation planning provides a strategic and scientifically defensible framework for doing this.
• 2. Pioneered in the terrestrial realm, there has been some scepticism associated with the applicability of systematic approaches to freshwater conservation planning. Recent studies, however, indicate that it is possible to apply overarching systematic conservation planning goals to the freshwater realm although the specific methods for achieving these will differ, particularly in relation to the strong connectivity inherent to most freshwater systems.
• 3. Progress has been made in establishing surrogates that depict freshwater biodiversity and ecological integrity, developing complementarity‐based algorithms that incorporate directional connectivity, and designing freshwater conservation area networks that take cognizance of both connectivity and implementation practicalities.
• 4. Key research priorities include increased impetus on planning for non‐riverine freshwater systems; evaluating the effectiveness of freshwater biodiversity surrogates; establishing scientifically defensible conservation targets; developing complementarity‐based algorithms that simultaneously consider connectivity issues for both lentic and lotic water bodies; developing integrated conservation plans across freshwater, terrestrial and marine realms; incorporating uncertainty and dynamic threats into freshwater conservation planning; collection and collation of scale‐appropriate primary data; and building an evidence‐base to support improved implementation of freshwater conservation plans.

Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Most fish destined for fishmeal production are food‐grade fish          下载免费PDF全文

Tim Cashion  Frédéric Le Manach  Dirk Zeller  Daniel Pauly 《Fish and Fisheries》2017,18(5):837-844

Marine fisheries target and catch fish both for direct human consumption (DHC) as well as for fishmeal and fish oil, and other products. We derived the fractions used for each for 1950–2010 by fishing country, and thus provide a factual foundation for discussions of the optimal use of fisheries resources. From 1950 to 2010, 27% (~20 million tonnes annually) of globally reconstructed marine fisheries landings were destined for uses other than DHC. Importantly, 90% of fish destined for uses other than DHC are food‐grade or prime food‐grade fish, while fish without a ready market for DHC make up a much smaller proportion. These findings have implications for how we are using fish to feed ourselves or, more appropriately, how we are not using fish to feed ourselves.  相似文献   

Yield response of sugar beets to water stress under Western European conditions   总被引：1，自引：0，他引：1  

Nirman Shrestha  Dirk Raes  Sarah Soentjens  Philippe Clouet 《Agricultural Water Management》2010,97(2):346-1316

The average yield of sugar beet has almost doubled within the last 30 years. With the raise in average yields and the increase in sensitivity to water stress of sugar beets, the yield response factor (Ky) derived by Doorenbos and Kassam (1979) needs an update. In this article, the soil water balance model BUDGET (Raes et al., 2006) was calibrated and validated to obtain correct estimations of the evapotranspiration deficit (1 − ETa/ETc, where ETa = actual crop evapotranspiration and ETc = maximum crop evapotranspiration under standard conditions) of sugar beets in two locations in France. Datasets of observed soil water contents of several years and different irrigation treatments were used. The simulated evapotranspiration deficits and observed yields were used to derive a seasonal Ky. The obtained linear and polynomial yield response relation between observed yield decline and evapotranspiration deficit showed a high goodness-of-fit. The coefficient of determination (R²) = 0.83, the Nash-Sutcliffe efficiency (EF) = 0.79, the relative root mean squared error (RRMSE) = 0.26 for linear; the coefficient of determination (R²) = 0.85, the Nash-Sutcliffe efficiency (EF) = 0.79, the relative root mean squared error (RRMSE) = 0.25 for polynomial). The results suggested a more pronounced response of sugar beet to water stress in Europe as compared to the values previously reported by Doorenbos and Kassam (1979). The comparison between the observed and simulated yields (with the updated Ky) for another site in France confirmed the findings.  相似文献