Angewandte Parasitologie最新文献

The paper starts with a historical reflection on the region and on famous scientific personalities which worked up parasitological problems on the territory of East Germany. Native scientists like J. L. Frisch, C. A. Rudolphi, R. Leuckart, A. C. Gerlach, R. Virchow, R. Koch, R. von Ostertag, W. Nöller, R. Wetzel made in fundamental contributions to the growth of knowledge in General and Special Parasitology. The parasitological institutions existing in East Germany are represented briefly. The parasitologists of East Germany, nearly 160,--biologists, physicians and veterinarians--among them more than 50 specialized parasitologists were associated in the Parasitological Society of the G.D.R. since 1961. A review is given of actual parasitological problems of agricultural and other domestic animals, fair game animals, of bees and freshwater fish as well as of the most important parasitoses of man frequent in East Germany, under the aspects of epidemiology, diagnosis and control. The rapid evolution of an intensive animal production under large scale management conditions required a permanent control of infestation with pathogenic protozoans, arthropods and helminths. Some selected results achieved in research and practice are represented. The epidemiological situation referring to parasitic zoonoses is favourable at present. Since 1970 a group of experts from East Germany working successfully in Mongolia on the systematic control of ectoparasites of farm animals together with Mongolian parasitologists. It is considered to be necessary to make an international agreement in parasitological research in future more than till now.

Often existing cross-resistance to structure analogous antimalarials causes the need to find new active compounds against malaria parasites. For this purpose the traditional medicine of tropical countries has proved to be a treasury. A root extract of Cochlospermum angolense showed in vitro a remarkable activity against Plasmodium berghei in the DNA synthesis measurement with 3H-labelled hypoxanthine. This effect could be reproduced under in vivo conditions with the "4-day suppressive test" of rodent malaria.

Ivomec in drinking water at dilutions of 1 ml/l (10 micrograms of Ivermectin/ml), 2.5 ml/l (25 micrograms of Ivermectin/ml) and 5 ml/l (50 micrograms of Ivermectin/ml) was successful against Myobia musculi and Myocoptes musculinus mange in naturally infected laboratory mice after 4 consecutive treatment days. One day before treatment drinking water was withheld. Ivermectin solutions were administered ad libitum.

Pathological effects of Apatemon cobitidis (Trematoda) in its second intermediate host, the bullhead (Cuttus gobio) are described. Macroscopically pathology in bullheads is characterized by migrating and encysted metacercariae in body cavity, eyes, retrobulbous space, brain and rarely in muscles and subcutis. Histologically lymphohistiocytic reactions and hemorrhages could be observed. Migration of metacercariae in eyes and invasion of brain causes blindness and inability to adapt to the background. Other main life functions remain intact.

Myxobolus dogieli infecting the heart muscles of carp was noted in a cage fishfarm situated in the upper Volga river. Prevalence of infection of two summer old fishes in different cages was 10-20%. Some of the fishes perished. One summer old carps had a lower infection. The disease takes place when the thermal efflusences of power stations are used.

It is known that some derivatives of the benzodiazepine group act not only as antipsychotic drugs but also have inhibitory effects on the growth of protozoa. The influence of imipramine and its derivatives clomipramine and desipramine on the multiplication of Crithidia luciliae, Leishmania mexicana amazonensis, Trypanosoma cruzi and Trichomonas vaginalis was investigated using in vitro cultivation of the parasites and compared with the effects of chlorpromazine and metronidazole. All trypanosomatides used were inhibited by imipramine and its derivatives with clomipramine having the strongest influence on the growth of parasites (ID50 12.5-35 micrograms/ml). The Trichomonas vaginalis strain used was susceptible to metronidazole but it was nearly resistant to the tricyclic compounds tested (ID50 greater than 100 micrograms/ml).

The development of Trypanosoma cruzi has been described both in vertebrate and invertebrate hosts, and the morphological transformations of the parasite have been studied in both cell-free cultures and tissue cultures. The investigators who studied this topic have emphasized the fact that the morphogenesis of T. cruzi may be associated with a series of factors. In the present study, we noted that when bloodstream trypomastigotes leave a vertebrate host reaching the digestive tract of triatomines through the blood sucking action of these vectors, specific culture by blood plating or maintenance of blood in physiological saline at different temperatures shows a phenomenon of trypanosome joining, with intensive movement of internal organelles (nucleus and kinetoplast) and junction at the kinetoplast level. Different situations may occur after this phenomenon, such as flagellate separation, passage of kinetoplast content from one individual to another, transformation into rounded elements that approach the pairs of agglomerate, or the formation of spherical elements similar to cyst-like bodies. When observed by light or phase-contrast microscopy, these bodies appear to be static and show inner structures moving in circles or in disorderly manner. On the basis of the molecular studies carried out by other authors, who observed that not all proteins synthetized from DNA are of immediate usefulness in the cell, but need to undergo activation by the action of another protein or of environmental variation, we may infer that T. cruzi, under adverse conditions, i.e. a change in habitat, may undergo transformations, taking on different forms for the exchange of genetic information for adaptation to the environment and for possible continuity of the evolutionary cycle.

This is the first study on the experimental susceptibility of the following species of molluscs: Cernuella (X.) cespitum arigonis, Helicella (H.) itala, Helicella ordunensis, Cochlicella barbara, Cepaea nemoralis and Helix (C.) aspersa, as intermediate hosts for the combination of both C. ocreatus and M. capillaris, pulmonary parasites in ruminants. Furthermore, the larval development of C. ocreatus and N. linearis, the two taken together, has been followed in Cernuella (X.) cespitum arigonis, H. ordunensis and C. nemoralis. Approximately 40 specimens of each of the above-mentioned species of molluscs were infected with the parasites listed. Bearing in mind the results obtained, we believe that while Cernuella (X.) cespitum arigonis, H. ordunensis, C. nemoralis, C. barbara and Helicella (H.) itala are suitable intermediate hosts for the larval combination of C. ocreatus and M. capillaris, the same cannot be said of Helix (C.) aspersa. Likewise, the first 3 species of molluscs quoted are ideal for the joint larval development of C. ocreatus and N. linearis. It seems that double infections favour larval development.

In carp during 1st year the course of dynamics of the 3 known stages of Sphaerospora renicola showed an increase of the kidney infection in winter and spring (with inhibited sporulation). The winter/spring-peak was accompanied by an intensive blood-phase (C-stages). After August of the 1st summer the swimbladder-phase (K-stages) was not observed, although SBI occurred between January and April. Under warm water condition this infection was discharged after September/October, the SBI never occurred after this time. In contrast to the 1st summer, affected kidneys were often found during winter and spring. In the period of the second outbreak of SBI, C-stages often occurred in the capillaries of swimbladder and in the kidney. The declining phases of SBI, observed from August to April, were not connected with the temperature conditions.

B. transfuga larvae migrated in livers, lungs and brains of experimentally infected mice. B. transfuga larvae have never been reported as etiologic agents of visceral larva migrans, but our results show that they have a migration in experimental paratenic hosts of a type that suggests their possible role in this syndrome.