Bacillus Influenzæ in Cases of Influenza.—On October 10, 1918, at the height of the epidemic at Camp Pike, search for B. influenzæ was made in a group of 23 consecutive cases of uncomplicated influenza from one to six days after the onset of the disease. From each individual simultaneous cultures on blood agar plates were made (a) from the nose, (b) from the throat, and (c) from the sputum, and the sputum from each case was injected into the peritoneal cavity of a white mouse. A similar study of 5 consecutive cases was made on November 19. The results are presented in Table II.
By means of multiple cultures taken simultaneously from different portions of the respiratory tract no difficulty was encountered in demonstrating B. influenzæ in all these cases of uncomplicated influenza. Not only was B. influenzæ found in all cases, but often in very large numbers predominating over all other bacteria on at least one of the plates from each patient, and in occasional instances occurring in nearly pure culture. One culture made about two hours after onset of the initial coryza is of interest. There was at the time a profuse serous nasal discharge. One drop of this allowed to fall on the surface of a blood agar plate gave a practically pure culture of B. influenzæ.
| Table II | |||||
|---|---|---|---|---|---|
| Presence of B. Influenzæ in 28 Cases of Influenza | |||||
| NO. | DAY OF DISEASE | NOSE | THROAT | SPUTUM CULTURE | SPUTUM PASSED THROUGH MOUSE |
| 1 | 1 | + | + | + | + |
| 2 | 4 | − | + | + | + |
| 3 | 5 | − | − | + | − |
| 4 | 4 | − | − | + | + |
| 5 | 3 | − | − | + | + |
| 6 | 4 | − | + | + | c |
| 7 | 2 | − | + | − | c |
| 8 | 4 | + | + | + | − |
| 9 | 5 | − | + | + | + |
| 10 | 2 | + | − | − | − |
| 11 | 2 | − | + | c | + |
| 12 | 3 | c | + | + | + |
| 13 | 3 | − | − | − | + |
| 14 | 2 | − | − | + | + |
| 15 | 3 | c | − | − | + |
| 16 | 1 | − | + | + | + |
| 17 | 3 | − | + | − | + |
| 18 | 4 | + | + | c | + |
| 19 | 6 | − | − | + | + |
| 20 | 1 | − | + | + | + |
| 21 | 2 | − | + | − | + |
| 22 | 4 | + | − | + | + |
| 23 | 3 | c | − | − | + |
| 24 | 2 | + | − | − | − |
| 25 | 1 | − | − | + | + |
| 26 | 5 | − | − | + | + |
| 27 | ? | − | + | − | + |
| 28 | 1 | − | − | + | + |
| 6 | 14 | 17 | 22 | ||
| c indicates that the plate was contaminated. | |||||
During the latter part of November and in early December a small secondary wave of influenza occurred at Camp Pike. In a series of 48 consecutive cases, B. influenzæ was readily found in all by means of combined throat cultures and mouse inoculation of the sputum, 33 times (68.7 per cent) in the throat cultures, 39 times (81.3 per cent) in the sputum. These cases were cultured on admission to the receiving ward of the hospital within twenty-four to forty-eight hours after onset and were all early cases of influenza without complications at the time the cultures were made. In 90 more consecutive cases in this series 62 or 68.9 per cent showed B. influenzæ in a single throat culture taken on admission.
A summary of all cultures made in cases of uncomplicated influenza is presented in Table III.
| Table III | |||
|---|---|---|---|
| Presence of B. Influenzæ in Cases of Influenza | |||
| METHOD | NUMBER OF CASES CULTURED | B. INFLUENZÆ FOUND | |
| NUMBER | PER CENT | ||
| Nose culture | 28 | 6 | 21.4 |
| Throat culture | 166 | 109 | 65.7 |
| Sputum culture | 28 | 17 | 60.7 |
| Sputum (mouse passage) | 76 | 61 | 80.3 |
| Combined nose, throat and sputum cultures and sputum inoculation | 28 | 28 | 100 |
| Combined throat cultures and sputum inoculation | 48 | 48 | 100 |
Of any single method used the intraperitoneal inoculation of a white mouse with a specimen of the patient’s sputum proved the most efficient in demonstrating the presence of B. influenzæ. No single method served to demonstrate B. influenzæ in all cases, but by simultaneous cultures from the nose, throat, and deeper air passages no difficulty was met in showing that B. influenzæ was invariably present, usually in abundance somewhere in the respiratory tract during the acute stage of the disease. This result is not out of harmony with the rapidly progressive character of the attack upon the mucous membranes of the respiratory tract in influenza.
Of interest in this connection are certain observations which suggest that the presence of B. influenzæ in predominant numbers at least is in many cases coincident with the acute stage of influenza and that the organisms show a tendency rapidly to diminish in abundance with the progress of the disease to recovery. In 82 cases of influenza cultured on the day of admission to the hospital, B. influenzæ was present in 52 (63.4 per cent) of the throat cultures. Repeated throat cultures in this group of cases from the fourth to the eighth day after admission when the temperature had fallen to normal, showed that B. influenzæ was still present in demonstrable numbers in the throat of only 25 cases or 30.5 per cent. Not only was there a material reduction in the number of patients in whom B. influenzæ could be demonstrated by the throat culture method, but the contrast in the predominance of B. influenzæ on the plates made early in the disease with those made during convalescence was often very striking. It is only fair to say, however, that some cases continued to carry B. influenzæ in their throats in large numbers throughout the period of observation.
Presence of Pneumococcus in Cases of Influenza.—It seemed of some importance to determine the prevalence of pneumococcus in cases of influenza, not because of any possibility that pneumococci might bear an etiologic relationship to the disease, but more by way of comparison with the prevalence of B. influenzæ, since both organisms are found in the mouths of normal individuals and are also frequently found together in the pneumonias that complicate influenza. The results obtained in cases of influenza early in the disease before the development of either a purulent bronchitis or of pneumonia are presented. The presence of pneumococcus was determined by the intraperitoneal inoculation of white mice with the saliva or sputum.
Twenty-four cases examined on September 27 and 28 gave the results shown in Table IV. These patients had been in the hospital from two to five days at the time the determinations were made.