Angewandte Parasitologie最新文献

To maintain the hatchability of miracidia, pure worm eggs of S. mansoni were collected in great quantities from liver and spleen of experimentally infected mice. For this purpose, the tissue was digested with papain, hyaluronidase and trypsin. Worm eggs in the residue were separated from remaining host cells, tissue materials and dead eggs by using the sieving chamber (sieves 200 microns x 200 microns and 28 microns x 28 microns) and by density gradient centrifugation.

Bulls artificially infected with a varying number of metacercariae of Fasciola hepatica were kept under uniform, standardized laboratory conditions. 6 months after the infection the daily range of variation and the distribution of the Fasciola eggs in the faeces were determined 3 times a day (morning, noon and afternoon) over two test periods, each of 5 days. This test, carried out in over 800 individual faeces samples, showed that the excretion of Fasciola eggs over a period of several days fluctuates considerably within one animal and within one infection group; the excretion of Fasciola eggs over one day varies widely at different times in each animal and also in each infection group; the distribution of Fasciola eggs in the faeces is always irregular within one day and also over several days in all animals. The variations demonstrated here must be taken into consideration when assessing the results of coproscopical diagnosis because studies of the faeces carried out on a single occasion can lead to completely incorrect conclusions being drawn.

With reference to a recent taxonomic revision the species of the echinostomes used in key studies on the population regulation in infections with 37-collar-spined Echinostoma species in experimental rodent hosts were reconsidered. This was considered essential to prevent taxonomic problems blocking further fruitful progress within this field of experimental parasitology.

Haemonchus contortus, incubated in 10 micrograms/ml and 50 micrograms/ml concentrations of Nilzan and albendazole in Tyrode solution were stained for histoenzymatic demonstration of various phosphatases, oxido-reductases and esterases. The intestine showed major alterations after drug treatments. The alkaline phosphatases (AkPase), adenosine triphosphatase (ATPase), glucose-6-phosphatase, succinic dehydrogenase (SDH), glutamate dehydrogenase (GDH), reduced nicotinamide adenine dinucleotide phosphate diaphorase and reduced nicotinamide adenine dinucleotide diaphorase showed a decreased activity in intestine after Nilzan treatment, whereas lactic dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G-6-PD) and monoamine oxidase resisted increased reaction. The albendazole treatment resulted in altered distribution pattern of the AkPase, ATPase, SDH, and GDH; while LDH, G-6-PD, and non-specific esterases exhibited slightly enhanced activity in the epithelium. The functional significance of these changes has been fully discussed.

The seasonality of infection of Bulinus (Ph.) globosus, the snail host of Schistosoma haematobium is reported. The pattern of snail infection was shown to vary with the type of habitats. The cercarial "transmission potential" was calculated based on the number of infected snails and the level of cercarial production. It is consequently assumed that the transmission pattern varies with season and habitat type. Dry season transmission potential was found to be high in running water habitats while low in stagnant water habitats. In the wet season, the reverse seems to be the case. The implication of these observations in the epidemiology of urinary schistosomiasis and in planning its control in the area is discussed.

During 1986/87, 922 carps have been examined for ectoparasitic helminths. Altogether 6 species of Gyrodactylus and 4 species of Dactylogyrus were found. The most frequent parasite on the gills was D. extensus; it shows a great tolerance to the water temperature with two peaks of infestation between 2 and 9 degrees C. Additionally, relationships between the seasonal dynamics of the invasion cycle of D. extensus and D. anchoratus were recognized. In addition to Dactylogyrus 2 species of Gyrodactylus, G. shumani and G. sprostonae occurred on the gills. G. shulmani tends to show rapid population growth in the warmest months in summer. The highest number of helminths were found in the beginning of September. It is conceivable that G. shulmani will be an agent of a new helminthosis in the GDR. The infestation by G. shulmani is often accompanied by the occurrence of D. vastator. Both species reach the maximum values approximately at the same time. G. sprostonae reached high intensities already in June and August. The common infestation increased by G. katharineri, G. stankovici and G. kherulensis on skin nd fins. G. katharineri seems to have the most favourable conditions in April. The indices dropped to a minimum in summer and autumn. G. stankovici has likely similar ecological claims as G. katharineri and shows a peak of incidence in April, too.

Conditionally, especially by using surface-water for drinking-water, G. lamblia must be regarded as a potential water-hygienic factor of risk. A review is given about the main methods for detecting the parasite in water. A successful one, worked out by Borsod Megyei Köjál, Miskolc (Hungary), is presented. The base is membrane filtration. A continuing concentration of the cysts is obtained by centrifugation and zinc-sulphate flotation. The diagnosis is realized microscopically. It is possible to conclude the number of viable infections cells and the hygienic dangerousness potential in the analyzed water resources from the examination of the ability of the isolated cysts to change themselves into the vegetative form of the agent under laboratory conditions.

More than 150 species of Diptera belonging to 46 families were caught in a flat in the outskirts of Berlin between April and October 1986. 2148 specimens were collected. Fannia canicularis was the most frequent species with 726 specimens. Drosophila melanogaster, Culex pipiens, Lucilia sericata, Sarcophaga carnaria, Calliphora vicina, Muscina stabulans and Fannia manicata were other important synanthropic flies, which inclusively Fannia canicularis amounted 55% of the total catching rate. The remaining species of Diptera have only an insignificant medical importance, because of the random occurrence in flats or of their small size. A brief assessment of the sanitary important species is given.

Haemaphysalis concinna and Dermacentor reticulatus mostly occur in narrow-limited humid biotopes of certain landscapes, whereas Ixodes ricinus--as wellknown--occurs more or less occupying the whole territory in kind of a mosaic; in regard of epidemiological questions at least, such a distribution may be resumed for Ixodes ricinus. Haemaphysalis concinna nearly regularly may be found in certain biotopes. Considering the possible role of Haemaphysalis concinna and Dermacentor reticulatus as vectors and reservoirs of transmissive agents special attention is paid to the transmitting of tick-borne borreliosis.

High losses due to metacercaria of Bucephalus polymorphus especially in cyprinids were observed in summer 1984 during a period of a sudden increase in water temperature. Pathology of diseased fish is described. Factors, such as eutrophication of the water system and overcrowding of distinct fish species, are discussed to be the main causes provoking outbreak of the parasitosis.