Recent Advances in Our Knowledge of Dengue and Sandfly Fever

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  • The Children's Hospital Research Foundation, University of Cincinnati College of Medicine, Cincinnati, Ohio


The chief advances in our knowledge of dengue during the past 2 years are in the demonstration that: 1) paralytogenic activity in intracerebrally inoculated monkeys of viruses submitted to prolonged passages in mice is due to the appearance of a new mutant and not to increased concentration of virus; 2) the Type 2, New Guinea “C” strain, after 18 passages in mice, has lost its virulence for man but not its immunogenic capacity; 3) early passage levels of both immunologic types of mouse-adapted virus possess sufficient “genetic stability” as regards propagation without appearance of the paralytogenic mutant, that fixed seed lots can be used for the preparation of a bivalent vaccine for human use; 4) specific hemagglutinins are associated with the 2 types of dengue virus and can be the basis of a simple in vitro serologic test for rapid diagnosis and epidemiologic survey.

The chief advances in our knowledge of sandfly fever during the past 2 years stem from the demonstration that mouse pathogenic mutants can be developed by propagation in newborn mice. The immunologically distinct Sicilian and Naples strains were both adapted to mice to a point where they are equally virulent for newborn and adult mice by the intracerebral route. Tests performed with the mouse-adapted Sicilian strain in human beings revealed that it lost its virulence but not its immunogenic capacity. These mouse-adapted strains provide new tools for diagnosis, epidemiologic survey and prevention of sandfly fever.