Differential characterization of emerging skin diseases of rainbow trout--a standardized approach to capturing disease characteristics and development of case definitions.

Farmed and wild salmonids are affected by a variety of skin conditions, some of which have significant economic and welfare implications. In many cases, the causes are not well understood, and one example is cold water strawberry disease of rainbow trout, also called red mark syndrome, which has been recorded in the UK since 2003. To date, there are no internationally agreed methods for describing these conditions, which has caused confusion for farmers and health professionals, who are often unclear as to whether they are dealing with a new or a previously described condition. This has resulted, inevitably, in delays to both accurate diagnosis and effective treatment regimes. Here, we provide a standardized methodology for the description of skin conditions of rainbow trout of uncertain aetiology. We demonstrate how the approach can be used to develop case definitions, using coldwater strawberry disease as an example.

Complete genome sequences of both biotypes of a virus pair of bovine viral diarrhea virus subgenotype 1k

We determined the complete genome sequences of both biotypes of a virus pair of bovine viral diarrhea virus (BVDV) subgenotype 1k. The viruses were isolated from a persistently infected calf suffering from mucosal disease. Compared to the noncytopathic biotype, the cytopathic biotype contains an insertion of 84 nucleotides and 22 nucleotide changes.

Climate change and infectious diseases of wildlife: Altered interactions between pathogens, vectors and hosts

Infectious diseases result from the interactions of host, pathogens, and, in the case of vector-borne diseases, also vectors. The interactions involve physiological and ecological mechanisms and they have evolved under a given set of environmental conditions. Environmental change, therefore, will alter host-pathogen-vector interactions and, consequently, the distribution, intensity, and dynamics of infectious diseases. Here, we review how climate change may impact infectious diseases of aquatic and terrestrial wildlife. Climate change can have direct impacts on distribution, life cycle, and physiological status of hosts, pathogens and vectors. While a change in either host, pathogen or vector does not necessarily translate into an alteration of the disease, it is the impact of climate change on the interactions between the disease components which is particularly critical for altered disease risks. Finally, climate factors can modulate disease through modifying the ecological networks host-pathogen-vector systems are belonging to, and climate change can combine with other environmental stressors to induce cumulative effects on infectious diseases. Overall, the influence of climate change on infectious diseases involves different mechanisms, it can be modulated by phenotypic acclimation and/or genotypic adaptation, it depends on the ecological context of the host-pathogen-vector interactions, and it can be modulated by impacts of other stressors. As a consequence of this complexity, non-linear responses of disease systems under climate change are to be expected. To improve predictions on climate change impacts on infectious disease, we suggest that more emphasis should be given to the integration of biomedical and ecological research for studying both the physiological and ecological mechanisms which mediate climate change impacts on disease, and to the development of harmonized methods and approaches to obtain more comparable results, as this would support the discrimination of case-specific versus general mechanisms

EPSTEIN-BARR VIRUS TRANSFORMATION OF B LYMPHOCYTE SUBPOPULATIONS

Epstein-Barr virus is a herpes virus distinguished by its remarkable specificity for the B lymphocyte of humans and certain other primates. Although the transformation process is very efficient, is has become clear that only a fraction of B lymphocytes is susceptible. Therefore the question may be raised if transformation is related to B cell stage of activation. B cells were purified from peripheral blood mononuclear cells by the removal of monocytes using elutriation and sheep red blood cell rosetting to remove T cells. Retesting B cells were purified using discontinuous Percoll gradients. Activation of resting cells for 24 hours with anti-mu or Staphylococcus aureus Cowan I (SAC) resulted in transition of susceptible cells into the G(,1) phase of the cell cycle as shown by an increase in cell size, an increase in uridine incorporation and an increase in sensitivity to B cell growth factor (BCGF). Entry into S phase was achieved by extending the period of activation to 48-96 hr as shown by an increase in thymidine incorporation. By this criterion, SAC activated cells entered S phase on day 2 and anti-mu treated cells on day 3. Control (G(,0)) cells and cells activated for varying lengths of time (G(,1), G(,1) plus S) were exposed to EBV and plated in a limiting dilution assay to determine the frequency of EBV-transformable cells. Control cells and cells activated for 24 hr had a precursor frequency of 1% to 2%. With continued activation, however, precursor frequency decreased as a function of the duration of activation. The decrease in frequency of transformable cells correlated with the entry of the population into S phase. The transformation frequency in the SAC-treated population was reduced twenty-fold on day 4, whereas in the anti-mu treated population it was reduced ten-fold. Treating cells with BCGF in conjunction with low concentrations of anti-mu decreased the transformation frequency to levels lower than anti-mu alone, further suggesting that entry into S phase is accompanied by a reduction in transformability. These results indicate that resting B cells are highly susceptible to transformation and that with in vitro activation into the cell cycle B cells become progressively insensitive to EBV. ^

A 170 year spring phenology index of plants in eastern China

Extending phenological records into the past is essential for the understanding of past ecological change and evaluating the effects of climate change on ecosystems. A growing body of historical phenological information is now available for Europe, North America, and Asia. In East Asia, long-term phenological series are still relatively scarce. This study extracted plant phenological observations from old diaries in the period 1834–1962. A spring phenology index (SPI) for the modern period (1963–2009) was defined as the mean flowering time of three shrubs (first flowering of Amygdalus davidiana and Cercis chinensis, 50% of full flowering of Paeonia suffruticosa) according to the data availability. Applying calibrated transfer functions from the modern period to the historical data, we reconstructed a continuous SPI time series across eastern China from 1834 to 2009. In the recent 30 years, the SPI is 2.1–6.3 days earlier than during any other consecutive 30 year period before 1970. A moving linear trend analysis shows that the advancing trend of SPI over the past three decades reaches upward of 4.1 d/decade, which exceeds all previously observed trends in the past 30 year period. In addition, the SPI series correlates significantly with spring (February to April) temperatures in the study area, with an increase in spring temperature of 1°C inducing an earlier SPI by 3.1 days. These shifts of SPI provide important information regarding regional vegetation-climate relationships, and they are helpful to assess long term of climate change impacts on biophysical systems and biodiversity.

Influence of experimental soil disturbances on the diversity of plants in agricultural grasslands

Aims and Methods Disturbance is supposed to play an important role for biodiversity and ecosystem stability as described by the intermediate disturbance hypothesis (IDH), which predicts highest species richness at intermediate levels of disturbances. In this study, we tested the effects of artificial soil disturbances on diversity of annual and perennial vascular plants and bryophytes in a field experiment in 86 agricultural grasslands differing in land use in two regions of Germany. On each grassland, we implemented four treatments: three treatments differing in application time of soil disturbances and one control. One year after experimental disturbance, we recorded vegetation and measured biomass productivity and bare ground. We analysed the disturbance response taking effects of region and land-use-accompanied disturbance regimes into account.Important Findings Region and land-use type strongly determined plant species richness. Experimental disturbances had small positive effects on the species richness of annuals, but none on perennials or bryophytes. Bare ground was positively related to species richness of bryophytes. However, exceeding the creation of 12% bare ground further disturbance had a detrimental effect on bryophyte species richness, which corresponds to the IDH. As biomass productivity was unaffected by disturbance our results indicate that the disturbance effect on species richness of annuals was not due to decreased overall productivity, but rather due to short-term lowered inter- and intraspecific competition at the newly created microsites.Generally, our results highlight the importance of soil disturbances for species richness of annual plants and bryophytes in agricultural grasslands. However, most grasslands were disturbed naturally or by land-use practices and our additional experimental soil disturbances only had a small short-term effect. Overall, total plant diversity in grasslands seemed to be more limited by the availability of propagules rather than by suitable microsites for germination. Thus, nature conservation efforts to increase grassland diversity should focus on overcoming propagule limitation, for instance by additional sowing of seeds, while the creation of additional open patches by disturbance might only be appropriate where natural disturbances are scarce.

[Diseases of the nails].

Nail alterations are frequently seen in daily practice, but they are often difficult to interpret. Basic knowledge of the anatomy and biology of the nail facilitates their diagnosis as this frequently allows their development and morphology to be explained. The following short review gives hints at the most important infections, inflammatory nail diseases and tumors.

The nature and treatment of diseases of the ear

by William Kramer. Transl. from the German, with the latest improvements of the author since the last German ed. by James Risdon Bennett

Grafts, A. S., Currier, H. B. y Stocking, C. R. - El agua en la fisiología vegetal (Water in the physiology of plants); 40 pp. Ed. por Chronica Botanica Company, Waltham, Mass. USA., 1949

Fil: H. G. C..