Hans-Joachim Gerth

Recombination of influenza a strains with fowl plague virus can change pneumotropism for mice to a generalized infection with involvement of the central nervous system

Abstract Recombination between fowl plague virus FPV/Rostock (Hav1N1), an influenza A strain which produces a generalized fatal infection with involvement of the central nervous system in chickens, and mouse lung-adapted human strains England/1/61 (H2N2) or PR/8/34 (H0N1 results in recombinants which produce a generalized infection in suckling mice with involvement of the central nervous system. A combination of the hemagglutinin and M protein from FPV/Rostock (Hav1N1) with certain polymerase proteins from the mouse lung-adapted strains produces generalized infections in mice. Infectious virus was present in lung, brain, and blood even after intranasal infection. A correlation between the ability to induce a generalized infection of suckling mice in vivo and the replication in mouse embryo fibroblasts in vitro could be demonstrated.

Hepatitis A-virus particles in stools of patients from a natural hepatitis outbreak in Germany

During a hepatitis outbreak in Southern Germany 27 nm particles were visualized by immune electron microscopy in stools of two patients. These particles were sereologically identical or similar to hepatitis A-virus particles identified in the USA. The buoyant density of these particles was 1.34 g/cm3 as shown by cesium chloride density centrifugation.The particles were first observed in small numbers in a stool obtained 11 days, and in large numbers in stools obtained 6 and 7 days before the onset of jaundice. Few particles were seen on the day of the onset of jaundice and none thereafter.In both patients a sereoconversion to hepatitis A-virus as judged by immune electron microscopy could be demonstrated.

Influenza Virus: Appearance of High Mouse-Neurovirulent Recombinants

Recombinants from two influenza A strains that lacked mouse neurovirulence were tested, along with their parent strains, for mouse neurovirulence and for the ability to propagate in dissociated mouse embryo brain cells. The parents used were (i) strain A/Rostock/34 (FPV) (Hav1N1), with a high chicken neurovirulence, and (ii) the mouse-lung-adapted human strain Engl/1/61 (H2N2), lacking neurovirulence. In some of the recombinants high mouse neurovirulence could be detected after intracerebral inoculation of low virus doses. There was neither a correlation between surface antigen and neurovirulence nor between neurovirulence and mouse lung virulence in our system, although neurovirulence was only found in strains with Hav1 hemagglutinin. There was an association between replication in mouse embryo brain cells in culture and high mouse neurovirulence.

Influenza Virus: Association of Mouse-Lung Virulence with Plaque Formation in Mouse Kidney Cells

In genetic recombination experiments with the mouse-lung-adapted human influenza A/Engl/1/61 (H2N2) and an avian influenza strain A/Rostock/34 (FPV) (Hav1N1) which is avirulent for the mouse lung, recombinants in which hemagglutinin and neuraminidase were either segregated (Hav1N2; H2N1) or not segregated (Hav1N1) were selected. The recombinants were studied for mouse-lung virulence and their ability to propagate in mouse kidney cells, mouse embryo fibroblasts, chick embryo kidney cells and chick embryo fibroblasts. An association between plaque formation in mouse kidney cells and mouse-lung virulence was found.

Subtype-specific identification of influenza virus in cell cultures with FITC labelled egg yolk antibodies

We report on results obtained with a direct immunofluorescence test for subtype-specific identification of influenza virus in detached cells of MDCK cultures after inoculation of 281 clinical specimens from patients with influenzalike disease. Influenza virus antibodies were produced in eggs from immunized hens and labelled with FITC. In 157 cases CPE was found in MDCK cells. A total of 57 cases of influenza A (H3N2), 86 cases of influenza A (H1N1), and 14 cases of influenza B were identified. In 33 cases of influenza A (H1N1) infection with massive CPE guinea pig but not chicken erythrocytes were agglutinated by the cell culture supernatants. The single step immunofluorescence test described proved easy to perform and results were obtained within 1 h after CPE was observed in contrast to the conventional HIT which is very time-consuming.

Immunofluorescence test with antigen-loaded erythrocytes: Detection of influenza virus specific IgG, IgA, and IgM antibodies

An immunofluorescence test (IFT) for the detection of influenza virus antibodies was established to supplement the standard serological diagnostical complement fixation test (CFT). Current strains (A/Philippines/2/ 82, A/Brazil/11/78, B/Singapore/222/79) were loaded on formalinized chicken erythrocytes. In contrast to CFT, we can distinguish specific immunoglobulin classes against influenza virus. Unlike CFT, IFT is subtype-specific. A recent infection can be distinguished from a past infection by the differentiation of specific immunoglobulin classes. Anticomplementary factors and hemolytic sera do not influence the result of the IFT. IFT does not require cell cultures and is easy to read.

Ergebnisse aus der Hepatitis A-Diagnostik des Hygiene-Instituts in Tübingen

Abstract The age-specific and seasonal distribution of serologically confirmed hepatitis A-cases in the area of Tubingen in southern Germany is reported. During 1978–1980 most of the hepatitis A-cases diagnosed by high anti-HAV-IgM titers occurred from September to December. The age distribution of patients with German names showed two age-related peaks, the first one in young children 5–10 years of age and a second one in young adults between 20–30 years. In patients with names suggesting mediterranean origin there is only one age-related peak in early childhood. A comparison of German children with children of foreign parents born and grown up in Germany shows an earlier infection and higher infection rate in the latter. The parents of these children are almost exclusively immigrant workers from mediterranean countries. Visits of the children to the home countries of their parents in which hepatitis A is very common are supposed to be of prime importance for the high prevalence and early occurrence of hepatitis A in this group.

Isolation of Single Stranded DNA from Purified Hepatitis A-Virus

Abstract Hepatitis A-Yirus-Single-Sranded D N A , Electron Microscopy, Length Measurements, Parvovirus Hepatitis A-virus was purified from human stools by three purification steps. Virus was identified by radioimmuno-assay and purity monitored with immune electron microscopy. Virus particles, serologically and morphologically identical, banded in CsCl in two density ranges at 1.31 — 1.34 g/cm3 and at 1.41 — 1.43 g/cm3. Virions of density 1.31 — 1.34 g/cm3 were shown to contain single-stranded D N A of different size classes. Class I 1.33 kb, class I I 4.61 kb in addition a small amount of molecules was de tected with lengths up to 15 kb.