A simple plaque-inhibition test for the study of arthropod-borne viruses.

The plaque-neutralization method developed by Dulbecco and co-workers for the study of the virus of western equine encephalomyelitis in cultures of chick fibroblasts, though probably unequalled for accuracy, has not been adopted for general use in laboratories engaged in research on the arthropod-borne viruses, for two reasons: (a) the belief that the technique would be suitable only for viruses with a powerful cytopathic effect on chick-embryo cells, and (b) the laborious procedures involved.The simple plaque-inhibition test described in this paper was devised with the requirements of the field or diagnostic laboratory in mind; while less precise than Dulbecco's method, this test is sufficiently accurate for many purposes and is far less laborious. The range of applicability of the technique is discussed, the author claiming that it can be used both as a qualitative test for the presence of neutralizing antibodies to a particular plaque-producing virus and as a test for the identification of unknown plaque-producing viruses.