[Infections with enterohemorrhagic Escherichia coli (EHEC)--results of an epidemiologic survey in Bavaria for the April 1996 to May 1997 time frame]. / Infektionen mit enterohämorrhagischen Escherichia coli (EHEC)--Ergebnisse einer epidemiologischen Erhebung in Bayern für den Zeitraum April 1996 bis März 1997.

Using a report system of the Bavarian Public Health services 300 EHEC infections were registered within one year (Apr 1, 1996, to Mar 31, 1997) in Bavaria. These consisted of 22 cases of haemolytic uraemic syndrome (HUS) (mean age, 2.8 yr), 6 cases of incomplete HUS (1.3 yr), 188 cases of enteritis (3.3 yr) and 84 asymptomatic infections (12.9 yr), respectively. From this follows an incidence rate for all infections of approximately 2.5 per 100,000 inhabitants and for HUS in the age group of children and juveniles up to 18 years of approximately 0.8, respectively. Possible sources (paths) of infection registered in relevant frequencies were: raw milk consumption (18% of the infected), farm-animal associated contact (43%), and contact with patients suffering from diarrhoea (36%).

[The microbe colonization of the palatine tonsils of healthy school age children]. / Mitteilung über die Keimbesiedelung der Gaumenmandeln bei gesunden Kindern im Einschulalter.

In 1988-1992 the tonsillar flora of 1799 children, six years of age and staying at certain kindergartens in Bavaria (Bayern), was examined. The microbiological investigations, directed at five indicator-germs showed the following results: 28.6% of the children were carriers of beta-haemolytic Streptococci, 17.4% of Enterobacteriaceae and 11.8% of Candida spp., Pseudomonadales and moulds could be found in 0.6% of the specimens.

[Vaccination in Germany--strategy, current status, deficits]. / Das Impfwesen in der Bundesrepublik Deutschland--Strategie, gegenwärtige Situation, Defizite.

In the Federal Republic of Germany all vaccinations are voluntary. They are performed by doctors in private practice and (to a lesser extent) by the public health service. Vaccinations against diseases of major public health importance are officially recommended by the superior health authorities. The strategy of public health service to achieve high levels of immunization coverage is reported. The main impediments for successful immunization programmes are imperfect reporting and information systems on target diseases and vaccination coverage.

[Simple in vitro test systems for determining the toxicity of environmental chemicals: microcultures of human lymphocytes and monoxenic ciliate cultures]. / Einfache in vitro-Prüfsysteme zur Toxizitätsbestimmung von Umweltchemikalien: Mikrokulturen menschlicher Lymphozyten und monoxenische Ciliatenkulturen.

Two test methods were developed to assess (I) the cytotoxicity, (II) the environmental toxicity of chemicals. Test parameter for (I) is the growth inhibition of human T-lymphocytes stimulated by PHA (test period 6-7 days), for (II) the inhibition of cell multiplication of the ciliate Tetrahymena pyriformis grown monoxenically in a chemically defined medium which contained glucose and citrate as only carbon source (test period 13-14 days). The EC50 values (mol/l) of Pb, Cd, Hg, dichlorvos, atrazine and lindane were for (I): greater than or equal to 10(-2,5), 10(-5,4), 10(-5,6), 10(-5,0), 10(-4,75) and 10(-3,95) respectively, for (II): 10(-6,72), less than or equal to 10(-6,66), 10(-7,84), 10(-3,61), 10(-3,93) and 10(-4,75) respectively. The advantages of the described bioassays are simple handling and high sensitivity.

[The effect of air pollution on the microbial colonization of the palatine tonsils]. / Der Einfluss von Luftverunreinigungen auf die Keimbesiedelung der Gaumenmandeln.

The prevalence of some facultatively pathogenic microorganisms in the tonsillar flora was studied in 10-years old children living in areas with different grades of air pollution during the years 1984-1986. Samples were examined for beta-hemolytic Streptococci, Enterobacteriaceae, Pseudomonas spp., Candida spp. and molds. Colonization by these microorganisms occurred more frequently in highly polluted towns (Frankfurt and Wiesbaden) than in less polluted areas (Freiburg and Starnberg). It is supposed that alteration of immune response or other defense mechanisms induced by some environmental pollutants enhance colonization by facultatively pathogenic bacteria and fungi.

[Epidemiology of hepatitis A and B and yellow fever in Zaire]. / Epidemiologie der Hepatitis A und B und des Gelbfiebers in Zaire.

In a sero-epidemiological study, clinically healthy persons from a rural area of Zaire were tested for antibodies against hepatitis A, B and yellow fever. There was a high prevalence of antibodies to hepatitis A-virus in early life: 90% of all children at the age of ten had antibodies in their sera. Similarly up to the age of 19 years almost 90% of all persons investigated were positive for hepatitis B (anti-HBc). The incidence of the hepatitis B-surface antigen in all ages was high. According to the method used, it totalled to 21% (capillary blood) or 32% (serum specimens). All these persons were asymptomatic HBsAg carriers. A carrier-rate of 20-30% is extremely high; it has been reported only in a few studies in tropical countries. 138 serum specimens from all age groups were tested for antibodies to yellow fever virus; 59 of them (43,4%) were positive. None of these persons reported a history of yellow fever; evidently they had undergone subclinical infections. Our findings show that yellow fever still is endemic in Central Africa. It may be concluded that all persons visiting Central Africa should be vaccinated against hepatitis A (passive prophylaxis), yellow fever and, if possible, against hepatitis B.

The effect of various interventions during a typhoid epidemic. Results of a simulation study.

This paper presents an epidemiological model for typhoid fever epidemics or paratyphoid diseases with an enteric course, as well as a deterministic approach for the quantitative representation of this model. The model has been tested against one typhoid and two paratyphoid epidemics which occurred in the Federal Republic of Germany. It was possible to simulate the course of these epidemics with sufficient precision, and to obtain information on the effects of various interventions (e.g. oral vaccination or hygiene measures).

[The pathogenesis of postvaccinal complications]. / Zur Pathogenese von Impfkomplikationen.

Paraspecific reactions to vaccines are -- induction of autoimmune mechanisms, -- immunosuppression, -- induction of inflammation (i.e. "reactogenicity"). These undesirable side effects of vaccination are important factors in pathogenesis of postvaccinal complications. Using the model of experimental vaccinia virus infection the paraspecific reactions could be demonstrated in several animal species. Cell mediated hypersensitivity to brain tissue antigen and basic encephalitogenic protein occurred following vaccinia infection in guinea pigs. In infected rabbits humoral anti-brain antibodies could be detected. The immune response to sheep erythrocytes in mice was tested by determining the number of plaque forming cells in the spleen after specific immunization. Vaccinia virus injected prior to or simultaneously with immunization strongly reduced the number of plaque forming cells in the spleen. The reactogenicity of bacterial and viral vaccines could be determined by means of a simple hemolytic plaque assay in mice. This assay represents the degree of enzymatic lysosomal activity of macrophages. The methods described might be useful to test the innocuity and tolerance of new vaccines.

Oral immunization against smallpox.

Attenuated vaccinia strain penetrates the mucous membranes of the oral and pharyngeal cavity; local lesions are not produced, even if high doses of attenuated virus are applied. Attenuated vaccinia virus thus offers the possibility of oral and nasal immunization against smallpox in man. Several groups of monkeys were immunized by the oral and nasal route. The subsequent challenge with virulent smallpox virus resulted in strongly mitigated clinical symptoms as compared to non-immunized controls. In the human, oral immunization with live attenuated virus was affected by the administration of virus-containing tablets. The procedures caused no untoward effect in primary vaccinees. Subsequent skin testing and conventional cutaneous vaccination resulted in accelerated takes, demonstrating successful oral pre-immunization.

[Sensitization against the antigens of the brain after experimental vaccinia infection. I. Evidence for cell-mediated immune response to brain-antigens (author's transl)]. / Sensibilisierung gegen Antigene des Zentralnervensystems nach experimenteller Infektion mit Vaccinia-Virus. I. Nachweis einer zellulären Sensibilisierung

Vaccinia virus infection was performed by scarification of the shaved skin (5 times 5 cm2) on the back of Pirbright guinea pigs. The macrophage migration inhibition test was performed with peritonealexudate cells 7, 11, 14 and 21 days after infection. Macrophage migration inhibition occurred after exposure of the cells to whole brain tissue antigen on the 7th, 11th, 14th day after infection (s. table 1). Lymphocyte transformation responses were examined by 14C-2-Thymidin uptake using blood cultures and basic encephalitogenic protein and whole brain tissue extract as antigens. A positive transformation response could be demonstrated from one to 8 weeks after infection (s. table 2). The specificity of the transformation response to brain antigen was established using control cultures stimulated with PHA or PPD. In no case stimulation occured with PPD. Stimulation with PHA was not altered. On the other hand the spontaneous lymphocyte transformation was enhanced at one week after infection and lymphocyte cultures exposed to heat inactivated vaccinia virus showed transformation from the 3th week after infection until the end of the observation period (i.e. 8 weeks) (s. table 2). The reason why cell mediated hypersensitivity to brain antigen is induced following vaccinia infection remains unknown. The most probable among several possible mechanisms seem a) the induction of virus-specific antigens on the surface of infected cells or b) the release of brain specific antigen through virus infection.