Accuracy of rotavirus diagnosis: modified genome electrophoresis versus electron microscopy.

530 human faecal samples were examined for the presence of rotavirus by electron microscopy (EM) and by a modified electrophoretic analysis of viral genome (PAGE). 516 stools gave identical results by both methods (97.4% agreement). The proportion of EM+, PAGE- samples (1/530) was significantly lower than the proportion of EM-, PAGE + samples (13/530) (P less than 0.01 with McNemar test). Relative sensitivity was 99.6% for PAGE and 95% for EM. False positive results could be excluded for each method because of the characteristic morphology of rotavirus particles (EM) and specificity of rotavirus electrophoretypes (PAGE). Discrepant cases were reexamined whenever possible and the causes of misdiagnosis are discussed.

[Serodiagnosis of human Yersinia infections. Preliminary results]. / Contribution au sérodiagnostic des infections humaines à Yersinia. Résultats préliminaires.

Preliminary data are reported on experience with newly developed complement-fixing (CF) antigens prepared from cultures of type 3 and type 9 Yersinia enterocolitica and from Yersinia pseudotuberculosis. Antigens were immunologically potent and not anti-complementary, thus making it possible to obtain satisfactory serologic tests. The results may be summarized as follows: 1. Yersinia CF antigens do not react with sera from healthy blood donors. There was only one low titer reaction with type 9 antigen among more than 300 serum samples tested. 2. There was a high degree of correlation between results of the agglutination tests and those obtained by CF. 3. There is no cross-reactivity by CF among the three Yersinia antigens if human sera are tested. A complete crossing was, however, obtained between type 9 Yersinia and Brucella abortus. 4. Hyperimmune sera frequently showed marked cross-reactivities in both CF and agglutination tests. 5. Human sera positive for various Salmonellae do not react in the CF tests with Yersinia antigens. It is felt that the new CF antigens may become an important tool for the detection of antibodies against Yersinia enterocolitica in the diagnosis of infectious diseases.

[Diphtheria toxin titration using "Staphylococcus aureus" protein A (author's transl)]. / Titrage de la toxine diphtérique utilisant la protéine A de Staphylococcus aureus.

The antigen-antibody reaction between diphtheria toxin and its corresponding IgG antibody may be visualized if IgG are adsorbed on the surface of S. aureus cells carrying protein A (SpA). If enough antigen is mixed with SpA--IgG, a visible agglutination occurs. On a glass slide, a rapid test can detect 0.3 Lf/ml toxin. If the mixtures are incubated overnight at 37 degrees C, the highest dilution of toxin producing agglutination is 0.01 to 0.02 Lf/ml for a given batch of toxin. The sensitivities of this or of the biological titration using the lethal effect on guinea-pigs are the same. The high sensitivity of the skin reaction was however not approached.

Ultrastructure and function in sympathetic ganglia isolated from rats infected with pseudorabies virus.

(1) After inoculation of the pseudorabies virus in the anterior chamber of the eye of the rat, virions can be found only in the neurons of the superior cervical sympathetic ganglion and in the sensory ganglion of the fifth nerve on the inoculated side. Other nervous structures--central or peripheral--are not infected. (2) It is shown that the retrograde axonal flow carries the virus from the eye to the sympathetic neurons. (3) The ultrastructure of the infected neuron has been studied at various intervals after inoculation and at different stages of the viral replication. (4) Excised infected ganglia in vitro show a spontaneous electrophysiological activity that can be recorded on both the post- and preganglionic nerve. Such an activity has never been seen in normal excised ganglion of rat. (5) The shape and frequency of the electrophysiological discharges recorded on the postganglionic nerve have been analyzed at various intervals after inoculation. (6) Correlations established between the ultrastructure, the effect of various drugs and the electrophysiological activity permit the proposal of various hypothesis about the abnormal activity of the infected neurons.

[Mycobacteria]. / Les mycobactéries

A brief review is presented of those properties of mycobacteria (genus Mycobacterium) which have a bearing on human medicine. The properties are set out in the form of tables covering the important cultural and biochemical tests used in taxonomy, resistance vs. sensitivity to a range of antituberculous drugs, and virulence and pathogenic effect in man and laboratory animals.

A latent guinea pig herpes-like virus: isolation and envelopment.

A guinea pig herpes-like virus (GPHLV) has been isolated from randomly selected guinea pigs. This virus is serologically related, if not identical, to the guinea pig herpes-like virus isolated by Hsiung-Kaplow. The frequency of latent infection in guinea pigs was found to be highly variable among animals of the same commercial origin. Ultrastructural studies have shown that the morphological development of this virus was similar to that reported for other herpes viruses in the early stages, but frequently differed at the envelopment stage. In the cytoplasm, virus particles were associated with electron-dense zones from which they acquired a thick and rough envelope.