[The prevalence of bronchial asthma in a selected sample of the adult Prague population]. / Prevalence bronchiálního astmatu ve vybraném vzorku dospelé Prazské populace.

The authors assessed the prevalence of bronchial asthma in 8458 18-year-old and older inhabitants of an economic area in Prague 8. The population of the area up to December 31, 1987 was 90,458 adults. The health communities were selected in a random way to comprise the central as well as peripheral parts of Prague 8. By means of questionnaires information was assembled from 70.9% of the respondents and after supplementation of data by various doctors the scope of information was 89.9% (7605/8458). For detailed examination 902 subjects were selected with "confirmed" and suspect symptoms of asthma. The anamnestic data were analyzed and pulmonary ventilation was examined (flow-volume), and depending on indication, also the provocation or bronchodilatation inhalation test, skin tests, and total IgE. The cumulative prevalence of bronchial asthma was 2.3% +/- 0.3% (174/7605). The highest prevalence values were in subjects under 20 years--3.5% and under 30 years--3.6%. The contemporary prevalence was 2.0% +/- 0.3% (152/7605). Nonatopic asthma was recorded in 54%, atopic asthma in 46% of the subjects.

Chemotherapy of experimental toxoplasmosis with special reference to robenidine.

Robenidine as an anticoccidial agent alone (in doses of 50 and 100 mg/kg) or in association with two other antiprotozoal compounds--pyrimethamine and sulfadoxine (in doses of 2.5 and 250 mg/kg, respectively) were tested in the treatment of chronically infected mice with an avirulent cyst-forming HF strain of Toxoplasma gondii. The efficacy of the used drugs was evaluated by the cysts number in the brains of treated mice versus control group, antibody level and viability of survived cysts by the consecutive infection of mice. According to these criteria none of the tested drugs alone or combined exhibited to be able to produce an effective cure of cyst-stage of toxoplasmosis in experimental mice.

Serological diagnostics of imported malaria in Czechoslovakia.

Two serologic techniques for malaria detection were compared in this study; the indirect fluorescent antibody (IFA) test used in 214 persons (38 Czechoslovak citizens returning from visits to tropical countries and 176 foreign visitors arriving to Czechoslovakia from areas endemic for malaria) and the indirect hemagglutination (IHA) test employed in 125 persons (29 Czechoslovak citizens and 96 foreigners). Comparisons revealed poor correlation between the IFA test and IHA test data. Of the two tests the IFA test appeared to be distinctly more reliable, more sensitive and more specific, the IHA test turned out to yield both false positive and false negative results. The antigen from Plasmodium gallinaceum gave lower IFA titres than P. falciparum antigen, but reacted with antibodies to all species of human plasmodia, and gave reliable test results. Positive serologic responses were appreciably more frequent in foreigners (46.0%) than Czechoslovak citizens (23.7%). The maximum percent positivity for malarial antibody was among individuals from tropical countries of Africa (74.6%), seropositivity in people from malaria endemic areas in Asia and Latin America was far less frequent (28.4% and 44.4%, respectively).

Preservation of laboratory strains of Toxoplasma gondii in vitro.

A procedure to obtain viable stabilates of virulent laboratory strains of Toxoplasma gondii with a prolonged storage life is described. Viable endozoites recovered from the sediment of mouse exudate or tissue cultures (LEP, HeLa) are suspended in Eagle's MEM medium supplemented with 10% calf serum and 10% dimethylsulfoxide and sealed into glass ampoules of 1-2 ml in volume. The ampoules are placed in an apparatus for gradual cell freezing, frozen to --35 degrees C at a rate of --1 degree C/min, and stored in liquid nitrogen. Reinoculation experiments on mice given the suspension intraperitoneally confirmed that such Toxoplasma gondii strains retain viability for at least 4 years. This in vitro preservation technique is compared with the analogous T. gondii preservation procedures described in the literature.

Toxoplasmosis in zoo animals.

Blood samples (collected and dried on filter paper) from 2 338 animals which had died in the zoological gardens in Berlin and other cities in the German Democratic Republic were examined by indirect haemagglutination test. Toxoplasma antibodies were found in 430 (18.3%) animals. Out of this number 1 113 were mammals and among them 201 (18.1%) were found to be positive. Out of 1 225 birds 228 (18.6%) were positive. A total of 194 species or subspecies (89 mammal species and 105 bird species) reacted positively. On the basis of these findings the spread of toxoplasma infection under zoo conditions as an artificial ecosystem in urban environment is discussed.

Density gradient centrifugation for separation of different stages of Toxoplasma gondii.

Suitable procedures for separation of various stages of Toxoplasma gondii by density gradient centrifugation have been delineated using peritoneal exudate of infected mouse as a model. Separation from host cells was effected by gradient centrifugation at 450 g for 30 minutes. Using Ficoll, dextran and sucrose, average parasite recoveries by pooling up to and including the peak fraction of 73.65%, 66.18% and 65.68% respectively were obtained. Toxoplasma trophozoites peaked at density of 1.040 g/ml with Ficoll, 1.060 g/ml with dextran and 1.110 g/ml with sucrose. In view of successful separation of exo-enteric stages of Toxoplasma by density gradient centrifugation, possible application of this method to isolation of various endo-enteric stages is discussed.

[Immunoepizootological study of ovine toxoplasmosis]. / Imunoepizootologická studie ovcí toxoplazmózy

The authors examined for toxoplasmosis (by means of an indirect hemagglutination reaction) 698 sheep kept in different places in Bulgaria. Out of this total number, 217 (= 31.1%) responded positively to the tests. In sheep delivering stillborn foetuses the positive response was much more frequent (43.3%) than in sheep with normal parturitions (21.0%). Sheep from montane regions showed a significantly higher positivity (40.3%) than sheep from lowland regions (18.3%). Three cystogenic strains of Toxoplasma gondii were isolated from six stillborn lambs. Out of the 493 sheep examined in Czechoslovakia, 33.3% gave a positive response in an indirect hemagglutination reaction, 29.7% responded in an indirect fluorescence reaction, and 11.6% in a microprecipitation reaction in agar gel. Attention is drawn to the epizootological and economic importance of the study of ovine toxoplasmosis.

The cat as a possible source of Toxoplasma infection for man.

The authors examined 1,027 persons divided into two groups by means of the toxoplasmin skin test. Group I contained 472 persons who owned domestic cats. Of these 255, i.e. 54.0% gave a positive reaction. Group II consisted of 555 persons who did not own cats. Of these 237, i.e. 42.7% reacted positively. A statistically significant difference at the 1% level of significance was assessed between the two groups. A difference of highest diagnostic importance was found in persons of unexposed occupations in the lowest age group, 14-19 years: 39.5% positive reactions among cat owners and 16.1% among those who did not own cats. The results support the assumption on the role played by domestic cats in the epidemiology of toxoplasmosis. An analysis of the ethology of the cat as regards its importance in the spread of Toxoplasma infection is the subject of the present study.