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Biomedical subjects

K Janitschke

Publications and source records attributed to K Janitschke.

At least 73 records · Page 4Linked to original sources

[Transmission of toxoplasma oocysts from domestic cats to rabbits (author's transl)].

The importance of the role of toxoplasma oocysts in the mode of spread of the infection for men and animal has differently been estimated. In own earlier experiments, we found out that the transmission of the infection by means of oocysts from cat to cat is not the rule. In a similar experimental setup, we tested now whether rabbits can be infected by getting into contact with faeces of cats containing sporulated toxoplasma oocysts (see table 1). 8 toxoplasma-free rabbits and two toxoplasma-free cats as control were placed on infectious faeces of 10 cats (group 1-8). As further controls served four non-infected rabbits being kept in the same cage (group 11-12). Four of eight rabbits which had been placed on the infectious faeces and one control animal having had no intended contact with those faeces got infected. Our experiments show that the question whether domestic cats have any significance as source of infection with toxoplasms cannot generally be answered. It has to be differentiated each time which mammal gets into contact with oocysts.

Animals↗

[Encephalitis due to Naegleria and Acanthamoeba. Comparison of organisms and diseases (author's transl)].

Naegleria and Acanthamoeba are ubiquitous, free-living amoebas. Infections with Naegleria are acquired nasally by exposure to water and are characterized by an acute fulminant hemorrhagic necrotizing meningoencephalitis leading to death. Acanthamoeba-infections occur in chronically ill, debilitated individuals. A patchy chronic or subacute granulomatous encephalitis is produced by hematogenous spread of the amoebas. The histological or clinical diagnosis is not difficult.

Amebiasis↗

[Studies on the viability of pathogenic amebae of the genus Naegleria in water of different sources (author's transl)].

Water specimens taken from the public water supply (A), a swimming-pool (B), and an inland lake (C) were infected with pathogenic amebae of the genus Naegleria (strain TY/Richmond). The specimens were stored at various temperatures for different periods. The water was then filtered and examined for naegleriae by animal inoculation. The results summarized in table 1 indicate that pathogenic naegleriae are viable at least for some weeks in warm tap and natural waters. Water from indoor swimming-pools however, may be a less suitable medium for the viability of pathogenic naegleriae.

Amoeba↗

Light and electron microscopical study on sarcocysts from muscles of the rhesus monkey (Macaca mulatta), Baboon (Papio cynocephalus) and Tamarin (Saguinus(=Oedipomidas) oedipus).

Sarcocystis cysts from muscles of monkeys (baboon, tamarin and rhesus monkey) were studied by means of light and electron microscopy. The differences in the morphology of the cyst wall and parasites clearly indicate that the three monkey species examined were each parasitized by at least a specific Sarcocystis species being not identical with S. nesbitti or S. kortei. The large numbers of cysts found within the muscle fibres point out the important role that have these monkeys as intermediate hosts in the life cycle of Sarcocystis species, where the final hosts are still unknown.

Animals↗

[Diagnostic significance of identification of anti-entamoeba histolytica antibodies (author's transl)].

Examinations were performed with the indirect immunofluorescence test (IFAT) and the indirect haemagglutination test (IHAT). Negative titers (less than 1:5) do not exclude an infection with E. histolytica. Titers up to 1:80 in both reactions are found in patients with negative stool specimens or indicate an asymptomatic infection of the intestinal lumen, an incipient or past symptomatic amoebiasis. IFAT values of 1:160 together with a negative or positive IHAT are also suggestive of the two last-mentioned types of infection. These titers are also found in patients with gastrointestinal disorders of other orgin. IFAT values higher than 1:60 with a positive IHAT are probably due to an invasive amoebiasis. Titres are, however, only diagnostic pointers.

Amebiasis↗

[The effect of toxoplasma antibodies after reinfection with T. gondii. III. Communication: investigations on the question of placental transmission of toxoplasma in immunised pregnant animals (author's transl)].

Investigations on whether theprotective effects of maternal defence mechanisms against T. gondii could prevent a placental transmission of the parasite to the foetus were carried out on pregnant rabbits and mice. With rabbits which were infected 6 to 1 month before the conception and showed a high infection immunity, there was never a transmission to the foetus and likewise at no time after reinfection of such maternal animals during the pregnancy. In mice which were latent infected with 11 different Toxoplasma strains, placental transmission succeeded with only 6 strains intrauterine infection of the foetuses were confirmed in 1 to 3%. After active immunisation of rabbits with non-multiplying antigen before the conception and later primary infection during the pregnancy, intrauterine transmission to the foetus could be detected in 55%. After passive immunisation with hyperimmune serum, infected foetuses could be ascertained in 79% of rabbits and 24% of mice. Possible intrauterine transmission to foetus protected by maternal defence mechanisms is likely to be dependent on various factors. 1. On the host species, 2. the state of immunity (infection immunity), 3. on Toxoplasma strain. An infection immunity with the presence of living parasites in maternal organism is probably dependent on Toxoplasma strain in mice and offers in rabbits an apparently certain protection against congenital infection. On the contrary, serologically detectable humoral antibodies after active or passive immunisation do not prevent a transplacental transmission. On the basis of experimental findings it has been concluded that at least the immunoglobulins of type IgG, IgA and IgM in lower titer ranges offer no protection against congenital transmission after reinfection during pregnancy. Also, the protective effect can not be based on the structure of respective placenta. The roles of cellular immune defence and other possible factors in this connection are discussed.

Animals↗

[Contribution to life-cycle of sarcosporidia in the Grant's gazelle].

We have been able to observ macro- and microscopically sarcosporidial cysts in the muscles of a Grant's Gazelle. Dogs and cats fed with these cysts shed oocysts and sporocysts in their feces, indicating that they both are the final hosts of the Sarcosporidia in Grants' Gazelle.

Animals↗

[Studies on the significane of sexual intercourse for the transmission of Toxoplasma gondii (author's transl)].

From 285 ejacula and 23 biopsy specimens of the testicles of men from childless marriages, no toxoplasms at all could be cultured in the mouse inoculation test. Testicles and accessory gonads of artificially infected male rabbits contained infective toxoplasms only up to the 29th day p.i. 8 artificially infected male rabbits did not transmit any agents through sexual intercourse to 13 toxoplasma-free female rabbits. One female animal became infected during the experiment. The route of infection is discussed. Experiments with ejacula of 4 artificially and freshly infected male rabbits did not lead to any Toxoplasma infection in mice, which had been inoculated with this material. From 50 testicles of sheep bound for slaughter, only in one case toxoplasms could be isolated in the mouse inoculation test. In virtue of the results in the literature and of our own experiments, the transmission of toxoplasms through sexual route does not seem to be of any vital epidemiological significance for men and animals.

Animals↗