Further Observations on the Filtrability of Yellow Fever Virus

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  • Yellow Fever Laboratory of the International Health Division of the Rockefeller Foundation, Bahia, Brazil

Recent studies on the filtrability of yellow fever virus have brought out, in addition to other interesting data, the following facts.

  1. 1.Yellow fever mosquito-virus, in the absence of serum, is frequently inactivated by exposures of one or two hours, at about 25°C. to normal saline solution, distilled water, Locke's solution, Ringer's solution, and hormone broth; hence the apparent non-filtrability of the mosquito-virus in certain instances. Even blood-virus loses its infectivity in a short time if dilution is carried much beyond 10 per cent (1).
  2. 2.If a sufficient quantity (10 per cent or more) of normal monkey serum be added to saline or distilled water suspensions of mosquito-virus, the virus survives for longer intervals and passes “V,” “N,” and “W” Berkefeld filters readily (2, 1). The virus has, however, been demonstrated in a Berkefeld ifitrate in distified water in the absence of serum (1).