A Study of the Etiology of Influenza

Abstract

In a previous communication 1 we have announced the cultivation of a filterable virus from 2 cases of typical influenza, one occurring in an epidemic of the interpandemic type in 1930 and the other during an outbreak of similar character in 1932. These 2 cultures when inoculated intranasally in human volunteers produced respiratory infections of the general type of the common cold but of considerable severity and with a tendency to greater constitutional reaction than is commonly observed after inoculation of cultures of common cold virus.

In March, 1934, there occurred in a small convalescent home for rheumatic children a local outbreak of influenza. The symptoms of the early cases were almost identical, consisting of malaise followed by fever as high as 104°F. and lasting for 3 days. During the height of the disease there was headache, general aching, nausea and vomiting. This was followed by marked weakness for several days. In the later stages of the epidemic the picture was that of a severe cold with only a slight rise in temperature. The leucocyte count was elevated rather than lowered as in some outbreaks of influenza.

Chick embryo tissue cultures were made from filtered nasopharyngeal washings obtained from 2 of the early cases of the disease. One of these cultures in the 18th generation, 2 months after isolation, was inoculated intranasally into 3 human volunteers under rigid quarantine. The results are presented in the following protocols.

Volunteer 93, a heavy, muscular man with no recent history of respiratory disease was inoculated intranasally with 3 cc. of culture R18. The inoculation was repeated 5 hours later. The next morning, 18 hours after the first inoculation, the subject manifested nasal obstruction, sneezing, mucoid nasal discharge, a productive cough and a slight malaise.