A Comparative Study of Standard Methods and Organ Culture for the Isolation of Respiratory Viruses

Fresh unfrozen specimens from 176 cases of acute respiratory infection and from 32 normal subjects, or patients without respiratory symptoms, were tested in parallel by direct inoculation into tissue cultures and suckling mice and also after the specimen had been passed in two organ cultures of human embryonic ciliated epithelium. Thirty-two agents were isolated by both methods: 26 only by the direct inoculation of tissue cultures and suckling mice, and 9 only after passage in organ culture.

Enteroviruses, herpes simplex virus and mumps virus were more readily isolated directly from the specimens than from the corresponding organ-culture fluid.

The only viruses isolated from the organ-culture fluids and not directly from the specimens were rhinoviruses. However, an almost equal number of these viruses were isolated directly from the specimens but not from the organculture fluid. It is postulated that these differences reflect the variation in the sensitivity to rhinoviruses of both the organ cultures and the kidney tissue cultures derived from different human embryos.

It is suggested that, in view of the limited supply of foetal material, it is uneconomical to test unfrozen specimens from respiratory infections in organ culture. This approach should be restricted to the examination of those specimens that fail to yield a possible aetiological agent by the standard methods.