Beschreibung:
<jats:p>Mice were inoculated with St. Louis encephalitis (SLE), Flanders (FLAN), California (CE), or Tensaw (TEN) viruses. At fixed intervals after inoculation, brains from these mice were collected and assayed for infective virus and complement-fixing, hemagglutinating, and precipitating antigens. Detectability of these antigens was correlated with the appearance of signs of illness in the mice. Infective virus appeared 64, 48, 48, and 40 hr before signs of illness and 90, 86, 64, and 56 hr before death in mice inoculated with SLE, FLAN, CE, and TEN viruses, respectively. Diagnostic antigens were also detected well before signs of illness appeared. These findings were applied to the isolation of viruses from field-collected specimens. It was shown that by harvesting tissues at appropriate intervals these viruses could be detected and identified more rapidly than by conventional techniques with mice.</jats:p>