Serodiagnosis of flaviviral infections and vaccinations in humans.

Young adult female mice, five to six weeks old, were injected intraperitoneally with 2·5 × 106·3 LD50 of dengue-2 virus, New Guinea C strain. The mice were killed on day 1, 2, 3, 4, 5, 6, 7, 10, 14, 21, 28 and 35 respectively. By means of the immunofluorescent antibody technique, viral antigen appeared as irregular granules in the reticuloendothelial cells of liver, lymph nodes and spleen of infected mice on the first day after inoculation and then diminished. From the fifth to sixth day of infection dengue antigen appeared again as homogeneous staining in the cytoplasm of single or groups of mononuclear cells in the lymphatic sinuses only. Later, by the third week of infection, dengue antigen could be seen in the mononuclear cells located in the marginal zone of lymphoid follicle of the spleen, the pattern of staining changing to bright spherical granules. At the same time, the deposition of immune complexes (composed of dengue antigen, mouse gamma and β1C globulin) could be seen in the renal glomeruli of infected mice. Serum antibody to dengue virus was found at low levels, being maximal on the 14th day after infection. Dengue virus was not isolated from the sera or from the infected organs. Granulomatous inflammation developed in lymph nodes and liver of mice infected with dengue virus and in mice inoculated with normal mouse brain suspension. Proliferative glomerular lesion was observed on day 14 after inoculation without definite abnormal urine findings.

Infection of young adult mice with dengue virus type 2

Dengue diagnosis was one of the topics discussed at "the adult dengue" presentations. In this paper, a review is presented focusing on the main challenges of dengue laboratory diagnosis. Accurate and efficient diagnosis of dengue is important for clinical care, surveillance support, pathogenesis studies, and vaccine research. Laboratory diagnosis is also important for case confirmation. Laboratory dengue diagnosis can be performed through virus isolation, genome and antigen detection and serological studies. For virus detection, dengue viremia is short, usually observed two or three days before onset of fever and lasts four to five days later. Therefore, samples for virus detection must be taken in the first four to five days of the disease during febrile phase. In recent years, PCR (polymerase chain reaction) has become an important tool as a quick method for diagnosis of dengue, another is detection of NS1 antigen, using commercial ELISA kit. Serological studies, for primary infection, the dominant immunoglobulin isotype is IgM, anti-IgM may appear during febrile phase (50% of cases), the other half, it appears within 2-3 days of defervescence. Once detectable, IgM levels rise quickly and appears to peak about 2 weeks after the onset of symptoms, then they decline to undetectable level over 2-3 months. Anti-IgG appears shortly afterwards with very low level. The physiological definition of a primary infection is therefore characterized by a high molar fraction of anti-dengue IgM and low molar fraction of IgG. Secondary dengue infections are characterized by a rapid increase in IgG antibodies, anti-dengue IgM appears in most instances, the level are dramatically lower.

Laboratory diagnosis of dengue virus infections.

Indirect immunofluorescence for serological diagnosis of dengue virus infections in Swedish patients.

Auteur(s) : Raymond Cesaire1, Andre Cabie2, Felix Djossou3, Isabelle Lamaury4, Gilles Beaucaire4, Laurent Thomas5, Yves Hatchuel6, Fatiha Najioullah1, Andre Yebakima7, Thierry Cardoso8, Philippe Quenel8, Philippe Dussart9 1Laboratoire de virologie-immunologie, JE2503, centre hospitalier universitaire de Fort-de-France, BP 632, 97261 Fort-de-France Cedex 2Service de maladies infectieuses et tropicales, centre hospitalier universitaire de Fort-de-France, BP 632, 97261 Fort-de-France Cedex 3Service [...]

Aspects récents de la dengue dans les départements français d’Amérique

One hundred eighty-three sera from two groups of children with dengue hemorrhagic fever and 37 control sera were examined for antibody against dengue virus by an indirect immunofluorescent method. When the reciprocal titer of 16 or higher was used as the diagnostic level, positive tests could be obtained in 80% of Group I and 100% of Group II sera after 3--6 days of fever. Positive tests were obtained in 100% of both groups after the first week of fever. There was no false-positive among the control sera. Preparation of the antigen is relatively easy, and the antigen may be stored for at least 3 months. The immunofluorescent method is rapid and simple, and is recommended for routine detection of serum antibody in dengue hemorrhagic fever.

Junya Siripont

Papers

Indirect fluorescent antibody technic for demonstration of serum antibody in dengue hemorrhagic fever cases.