ULTRAFILTRATION OF RECENTLY ISOLATED NEUROTROPIC VIRUSES

Abstract

On the basis of filtration through graded collodion membranes, 11 recently discovered neuroptropic viruses fall into 2 groups according to size: the larger, with filtration end points approximating 150 m[mu], includes Anopheles A, Anopheles B, Wyeomyia, Ntaya, Bwamba fever, and Bunyamwera viruses; the group of smaller viruses includes West Nile, Semliki forest, Zika, Ilheus, and Uganda S, each having filtration end points in the 45-61 m[mu] range. The calibration of 5 or more disks per sheet and the rejection of all lots showing high calibration variability, as proposed by Bugher, ensure that the error of the method of ultrafiltration will be reduced appreciably.