504 research outputs found

    Nematode control in 'green' ruminant production systems

    Get PDF
    Collectively, nematode parasites of domestic ruminants continue to pose the greatest disease problem in grazing livestock systems worldwide, despite the powerful and extensive chemotherapeutic arsenal available for their control. The widespread development of anthelmintic resistance, particularly in nematode parasites of small ruminants, and the trend towards nonchemical (ecological, organic, green) farming of livestock has provided an impetus for the research and development of alternative parasite control methods. This article provides a brief overview of the non-chemotherapeutic options for parasite control and how they might play a role either in organic farming or in other low-input farming systems

    Domestication of ruminant livestock and the impact of nematode parasites:possible implications for the reindeer industry

    Get PDF
    In a balanced ecological system, both host and nematode parasite populations are firmly controlled by a complex array of interacting factors. However domestication of livestock has tipped the balance in favour of the parasites. This is due to increasing the proportion of susceptible animals in the herd or flock (lactating females and weaned young animals), increasing stocking rate, increasing productivity demands and decreasing the movement of the animals. In contrast with microbial infections, where multiplication takes place entirely within the host, metazoan parasites have both a parasitic phase and a free-living phase. Every worm present has been separately acquired by the ingestion of free-living stages on pasture. Immunity to nematodes develops slowly, it is labile, and its maintenance is dependent upon a good nutritional state of the animal. Consequently, worm parasites are ubiquitous wherever livestock are kept and they impose a constant and often a high infectious pressure on grazing animals. Nematode infections in grazing livestock are almost always a mixture of species. All have deleterious effects and collectively lead to chronic ill thrift. Economic evaluations repeatedly show that the major losses due to parasites are on animal production, rather than on mortality. This paper focuses on the problems of nematode parasites; problems associated with drug use (anthelmintic resistance, environmental impact) and costs of nematode infections for the common ruminant livestock industries (cattle, sheep, goats), with possible analogies for the semi-domesticated reindeer industry

    Prevalence of gastrointestinal nematodes in winter slaughtered reindeer of northern Finland

    Get PDF
    The objective of this study was to determine the prevalence and intensity of gastrointestinal nematodes in winter-slaughtered reindeer during 2002-2004, from northern reindeer herding cooperatives in Finland. Ostertagia gruehneri of the abomasum was prevalent with low levels of infections in 100% of calves, (n = 53; mean ≈ 1300 worms per animal) and in 98% of adults, (n = 41; mean ≈ 3900 worms per animal). There was no difference in the number of O. gruehneri between male and female calves. The proportion of O. gruehneri inhibited larvae was significantly higher in calves (81%) than in adult reindeer (39%) (P = 0.005). The intestinal nematodes, Nematodirus tarandi and Nematodirella longispiculata, were detected only in reindeer calves. The numbers of these worms did not differ between male and female calves, but there was a difference in abundance between sites. High prevalence and low intensity of gastrointestinal nematodes characterized the patterns of infection of the reindeer examined in this study. It is assumed that these infections are sub-clinical and would not contribute to productivity losses.Abstract in Finnish / Lyhennelmä:Ruuansulatuskanavan sukkulamatojen esiintyminen talvella teurastetuissa pohjoissuomalaisissa poroissa Tämän työn tavoitteena oli määrittää ruuansulatuskanavan sukkulamatojen prevalenssi ja tartunnan aste talvella teurastetuissa Suomen pohjoisten paliskuntien poroissa vuosina 2002-2004. Juoksutusmahan Ostertagia gruehneri –loisella oli korkea prevalenssi, mutta infektion aste (matojen lukumäärä) oli melko matala; 100% vasoista oli infektoituneita (n = 53; keskimäärin 1300 matoa mahassa) ja 98% aikuisista (n = 41, keskimäärin 3900 matoa). Juoksutusmahamatojen määrissä ei ollut eroja naaras- ja urosvasojen välillä. Kehityksessään estyneiden (pysähtyneiden) O. gruehneri –matojen osuus oli tilastollisesti merkitsevästi korkeampi vasoilla (81%) kuin aikuisilla poroilla (39%) (P = 0.005). Suolistosukkulamatoja Nematodirus tarandi ja Nematodirella longispiculata tavattiin ainoastaan vasoilla. Näiden matojen määrä ei eronnut naaras- ja urosvasojen välillä, mutta maantieteellisiä eroja yleisyydessä havaittiin. Tutkimuksen poroille leimallinen loisten korkea prevalenssi ja matala infektioaste viittaa oireettomuuteen ja siihen, että ne ehkä eivät aiheuta tuotantotappioita. Abstract in Norwegian / Sammendrag: Prosentvis forekomst (prevalens) av rundmark (nematoder) i mage-tarm fra vinterslakta rein i nordlige Finland Studien ble gjennomført på rein (Rangifer tarandus tarandus) fra nordlige reindistrikter i Finland i perioden 2002 til 2004. Rundmarken Ostertagia gruehneri fra løpemagen var vanlig og fantes i lavt infeksjonsnivå (dvs. i relativt lite antall) i alle undersøkte kalver (100% forekomst i 53 dyr med et gjennomsnittlig antall marker per kalv på ca 1300) og i 98% av de 41 undersøkte voksne dyrene der gjennomsnittet per voksent dyr var ca 3900 marker. Andelen med hvilende (inhiberte) larver var statistisk sannsynlig høyere i kalver (81%) enn i voksen rein (39%) (P = 0.05). Tarmnematodene Nematodirus tarandi og Nematodirella longispiculata fantes bare i kalver. Her varierte prosentvis infeksjon fra 25% til 100% i flokkene. Det var ingen forskjell i intensitet (antall mark) mellom han- og hunkalver. Høy prevalens og lav intensitet var det karakteristiske infeksjonsmønsteret i denne studien. Vi antar derfor at infeksjonene er ubetydelige (er subkliniske) og at de ikke vil bidra til produksjonstap

    IPD—the Immuno Polymorphism Database

    Get PDF
    The Immuno Polymorphism Database (IPD) (http://www.ebi.ac.uk/ipd/) is a set of specialist databases related to the study of polymorphic genes in the immune system. IPD currently consists of four databases: IPD-KIR, contains the allelic sequences of Killer-cell Immunoglobulin-like Receptors; IPD-MHC, a database of sequences of the Major Histocompatibility Complex of different species; IPD-HPA, alloantigens expressed only on platelets; and IPD-ESTAB, which provides access to the European Searchable Tumour Cell-Line Database, a cell bank of immunologically characterized melanoma cell lines. The IPD project works with specialist groups or nomenclature committees who provide and curate individual sections before they are submitted to IPD for online publication. The IPD project stores all the data in a set of related databases. Those sections with similar data, such as IPD-KIR and IPD-MHC share the same database structure. The sharing of a common database structure makes it easier to implement common tools for data submission and retrieval. The data are currently available online from the website and ftp directory; files will also be made available in different formats to download from the website and ftp server. The data will also be included in SRS, BLAST and FASTA search engines at the European Bioinformatics Institute

    A comparison of high-throughput techniques for assaying circadian rhythms in plants

    Get PDF
    Over the last two decades, the development of high-throughput techniques has enabled us to probe the plant circadian clock, a key coordinator of vital biological processes, in ways previously impossible. With the circadian clock increasingly implicated in key fitness and signalling pathways, this has opened up new avenues for understanding plant development and signalling. Our tool-kit has been constantly improving through continual development and novel techniques that increase throughput, reduce costs and allow higher resolution on the cellular and subcellular levels. With circadian assays becoming more accessible and relevant than ever to researchers, in this paper we offer a review of the techniques currently available before considering the horizons in circadian investigation at ever higher throughputs and resolutions

    Individual and Population Level Variation in the Reproductive Potential of Deep-Sea Corals From Different Regions Within the Gulf of Maine

    Get PDF
    Deep-sea corals are of conservation concern in the North Atlantic due to prolonged disturbances associated with the exploitation of natural resources and a changing environment. As a result, two research cruises in the Gulf of Maine region during 2014 and 2017 collected samples of two locally dominant coral species, Primnoa resedaeformis and Paramuricea placomus, at six locations to investigate reproductive ecology. Remotely operated vehicles (ROVs) were used to collect specimens that were examined via paraffin histology, and coincident video surveys were used to determine size class distributions. Both species were identified as gonochoristic, and sampled locations exhibited dissimilarities in spermatocyst development and oocyte size except for those in close geographic proximity. Fecundities exhibited substantial ranges across sample locations and average oocyte sizes (±SD) were 140 ± 117 μm for P. resedaeformis and 64 ± 46 μm for P. placomus. In addition, colony size distributions were also significantly different across sampling locations. Notably, the Outer Schoodic Ridge sample location, with larger colony and oocyte sizes, was identified as a potential key source population of reproductive material in the Gulf of Maine. These data were used to calculate differences in reproductive potential based on relationships between colony morphology and reproductive output using height as a predictive proxy. Furthermore, calculated age at first reproduction, 7.6–19.8 years for P. resedaeformis and 20.7–37 years for P. placomus, which may be dependent on sex of the colony, provides a metric for estimating the amount of time these coral habitats will take to recover. This investigation, in response to historical population impacts and environmental change, links reproductive and morphometric relationships to inform population scale reproductive models, while also establishing an understanding of regional scale gametogenic variability within the Gulf of Maine region

    Meeting radiation dosimetry capacity requirements of population-scale exposures by geostatistical sampling.

    Get PDF
    BACKGROUND: Accurate radiation dose estimates are critical for determining eligibility for therapies by timely triaging of exposed individuals after large-scale radiation events. However, the universal assessment of a large population subjected to a nuclear spill incident or detonation is not feasible. Even with high-throughput dosimetry analysis, test volumes far exceed the capacities of first responders to measure radiation exposures directly, or to acquire and process samples for follow-on biodosimetry testing. AIM: To significantly reduce data acquisition and processing requirements for triaging of treatment-eligible exposures in population-scale radiation incidents. METHODS: Physical radiation plumes modelled nuclear detonation scenarios of simulated exposures at 22 US locations. Models assumed only location of the epicenter and historical, prevailing wind directions/speeds. The spatial boundaries of graduated radiation exposures were determined by targeted, multistep geostatistical analysis of small population samples. Initially, locations proximate to these sites were randomly sampled (generally 0.1% of population). Empirical Bayesian kriging established radiation dose contour levels circumscribing these sites. Densification of each plume identified critical locations for additional sampling. After repeated kriging and densification, overlapping grids between each pair of contours of successive plumes were compared based on their diagonal Bray-Curtis distances and root-mean-square deviations, which provided criteria ( RESULTS/CONCLUSIONS: We modeled 30 scenarios, including 22 urban/high-density and 2 rural/low-density scenarios under various weather conditions. Multiple (3-10) rounds of sampling and kriging were required for the dosimetry maps to converge, requiring between 58 and 347 samples for different scenarios. On average, 70±10% of locations where populations are expected to receive an exposure ≥2Gy were identified. Under sub-optimal sampling conditions, the number of iterations and samples were increased, and accuracy was reduced. Geostatistical mapping limits the number of required dose assessments, the time required, and radiation exposure to first responders. Geostatistical analysis will expedite triaging of acute radiation exposure in population-scale nuclear events
    • …
    corecore