Search results for "host"
showing 10 items of 1982 documents
Phenotypic analysis of adults and eggs of Fasciola hepatica by computer image analysis system
2005
AbstractKnowledge of the morphological phenotypes of the liver fluke Fasciola hepatica (Trematoda: Digenea) is analysed. The influence of parasite age on its dimensions, the adult fluke growth model, variation in a biometric variable versus time, and variation in a biometric variable versus another biometric variable (allometric model) are revised. The most useful allometric model appears to be (y2m]#x2212;y2)/y2=c [(y1m−y1)/y1]b, where y1=body area or body length, y2=one of the measurements analysed, y1m, y2m=maximum values towards which y1 and y2, respectively, tend, and c, b=constants. A method based on material standardization, the measurement proposal and allometric analysis is detaile…
Climate change effects on trematodiases, with emphasis on zoonotic fascioliasis and schistosomiasis.
2009
The capacity of climatic conditions to modulate the extent and intensity of parasitism is well known since long ago. Concerning helminths, among the numerous environmental modifications giving rise to changes in infections, climate variables appear as those showing a greater influence, so that climate change may be expected to have an important impact on the diseases they cause. However, the confirmation of the impact of climate change on helminthiases has been reached very recently. Only shortly before, helminthiases were still noted as infectious diseases scarcely affected by climate change, when compared to diseases caused by microorganisms in general (viruses, bacteriae, protozoans). Th…
Fascioliasis and other plant-borne trematode zoonoses
2005
Fascioliasis and other food-borne trematodiases are included in the list of important helminthiases with a great impact on human development. Six plant-borne trematode species have been found to affect humans: Fasciola hepatica, Fasciola gigantica and Fasciolopsis buski (Fasciolidae), Gastrodiscoides hominis (Gastrodiscidae), Watsonius watsoni and Fischoederius elongatus (Paramphistomidae). Whereas F. hepatica and F. gigantica are hepatic, the other four species are intestinal parasites. The fasciolids and the gastrodiscid cause important zoonoses distributed throughout many countries, while W. watsoni and F. elongatus have been only accidentally detected in humans. Present climate and glob…
Low-altitude outbreaks of human fascioliasis related with summer rainfall in Gilan province, Iran
2011
Following human fascioliasis outbreaks in 1988 and 1999 in Gilan province, northern Iran, efforts are now made to shed light on the seasonal pattern of fascioliasis transmission in this endemic area, taking into account snail host populations, climatic conditions and human cases. Populations of the intermediate host snail (Lymnaea spp.) peak in May and November, while there is a fourfold increase in the rate of human fascioliasis in February compared to that of September. Transmission is likely to occur mainly in late autumn and sporadically in late spring. Rainfall, seasonally analysed in periods of 3 years, indicates that accumulated summer rainfall may be related with the 1988 and 1999 h…
Aggregation ofArgulus coregoni(Crustacea: Branchiura) on rainbow trout (Oncorhynchus mykiss): a consequence of host susceptibility or exposure?
2005
By sampling individual rainbow trout,Oncorhynchus mykiss, at a fish farm we showed thatArgulus coregoniwere aggregated within their host population. The relative significance of susceptibility and exposure generating the observed pattern was tested using experimental infections. We examined, whether rainbow trout developed protective resistance mechanisms against the louse following a challenge infection and if there was variation between individual trout in their susceptibility toA. coregonimetanauplii. Fish were exposed to 20A. coregonifor 5, 25, 50, 85 or 120 min and the numbers attaching recorded. Three weeks later, developing argulids were removed and the experiment repeated with a sta…
Priming of host resistance to protect cultured rainbow trout Oncorhynchus mykiss against eye flukes and parasite-induced cataracts
2010
In the present study, immunologically naive rainbow trout Oncorhynchus mykiss were experimentally exposed to a low-level Diplostomum spathaceum (Trematoda) infection to stimulate acquired resistance and, along with unexposed controls, were subsequently exposed to natural infection for 8 weeks. The priming of the host resistance, designed to simulate a procedure applicable in aquaculture, decreased the number of establishing parasites compared to untreated controls by the end of the experiment. This effect was slow and did not protect the fish against the parasite-induced cataracts. The results suggest that this type of priming of host resistance is probably inefficient in preventing the del…
Intensive fish farming and the evolution of pathogen virulence: the case of columnaris disease in Finland.
2009
Ecological changes affect pathogen epidemiology and evolution and may trigger the emergence of novel diseases. Aquaculture radically alters the ecology of fish and their pathogens. Here we show an increase in the occurrence of the bacterial fish disease Flavobacterium columnare in salmon fingerlings at a fish farm in northern Finland over 23 years. We hypothesize that this emergence was owing to evolutionary changes in bacterial virulence. We base this argument on several observations. First, the emergence was associated with increased severity of symptoms. Second, F. columnare strains vary in virulence, with more lethal strains inducing more severe symptoms prior to death. Third, more vir…
Efficient and portable acceleration of quantum chemical many-body methods in mixed floating point precision using OpenACC compiler directives
2016
It is demonstrated how the non-proprietary OpenACC standard of compiler directives may be used to compactly and efficiently accelerate the rate-determining steps of two of the most routinely applied many-body methods of electronic structure theory, namely the second-order M{\o}ller-Plesset (MP2) model in its resolution-of-the-identity (RI) approximated form and the (T) triples correction to the coupled cluster singles and doubles model (CCSD(T)). By means of compute directives as well as the use of optimized device math libraries, the operations involved in the energy kernels have been ported to graphics processing unit (GPU) accelerators, and the associated data transfers correspondingly o…
Degradation of dimeric lignin model compounds by aerobic bacteria isolated from the hindgut of xylophagous termites.
1997
The capability of the intestinal flora from the gut of xylophagous termites of degrading lignin model compounds was investigated. Different dimeric lignin model compounds-degrading bacteria were obtained from the hindgut flora of Mastotermes darwiniensis FROGGATT, Reticulitermes santonensis FEYTAUD, Nasutitermes nigriceps HALDEMAN and Zootermopsis angusticollis HAGEN. In the presence of oxygen dimeric model compounds were degraded by all isolates. This indicates that the hindgut flora of termites is basically able to produce substrate for their host from aromatic extractives of wood.
Profil Tempat Tumbuh Sarang Semut (Myrmecodia spp.) Di Distrik Manokwari Selatan Papua Barat
2019
Papua has a very high diversity of flora species, one of which is a type of Sarang Semut. Different growing conditions will affect the level of diversity of plants. For that information about the place to grow Ant Plant is needed as basic information for the development of the cultivation of Ant plants. The method used is descriptive method with field observation technique. The results showed that the type of ant nest plant found in South Manokwari was a type of Myrmecodia pendans and Myrmecodia cf. schlechteri. Both of these species do not grow evenly in all study locations even at the same height, this plant has a characteristic growing place: it grows on host trees that are not slippery,…