The prevalence of B. influenzæ in cases of measles during the period of the influenza epidemic corresponded very closely with that found in normal individuals under similar circumstances. The increasing proportion of cases carrying B. influenzæ as the epidemic of influenza advanced is further evidence of the wide dissemination of the organism during the epidemic.
| Table XI | |||
|---|---|---|---|
| Incidence of B. Influenzæ in 830 Throat Cultures in 487 Cases of Measles; Cultures Repeated at Weekly Intervals | |||
| DATE | NUMBER OF CASES | B. INFLUENZA FOUND | |
| NUMBER | PER CENT | ||
| Sept. 10–15 | 47 | 15 | 31.9 |
| Sept. 16–29 | 106 | 33 | 31.1 |
| Sept. 30–Oct. 6 | 122 | 38 | 31.1 |
| Oct. 7–13 | 235 | 96 | 40.8 |
| Oct. 14–20 | 320 | 157 | 49.1 |
| Total | 830 | 339 | 40.8 |
| Table XII | ||||||
|---|---|---|---|---|---|---|
| Total Number of B. Influenzæ Carriers Among 223 Cases of Measles as Determined by Repeated Throat Cultures at Weekly Intervals after Admission to Hospital | ||||||
| TIMES CULTURED | NUMBER OF CASES | NUMBER OF CULTURES | B. INFLUENZÆ FOUND | TOTAL CARRIERS IN ONE OR MORE CULTURES | ||
| NUMBER | PER CENT | NUMBER | PER CENT | |||
| 2 | 129 | 1st | 37 | 28.7 | 82 | 63.6 |
| 2nd | 63 | 48.8 | ||||
| 3 | 69 | 1st | 20 | 28.9 | 52 | 75.4 |
| 2nd | 31 | 44.9 | ||||
| 3rd | 33 | 47.8 | ||||
| 4 | 25 | 1st | 6 | 24 | 21 | 84.0 |
| 2nd | 10 | 40 | ||||
| 3rd | 13 | 52 | ||||
| 4th | 14 | 56 | ||||
It is evident from the figures presented in Table XII that a large percentage of the measles cases studied were at one time or another carriers of B. influenzæ. In consideration of this fact, it must be borne in mind that all these cases were cultured during the period when the influenza epidemic was at its height and that many of these cases had influenza while in the hospital for measles. No data are available as to the exact number, since a definite diagnosis of influenza could hardly be made during the acute stage of measles. It is probable that approximately 25 per cent developed influenza, since that was the incidence of influenza in the total population of Camp Pike. The consistent increase in the percentage of influenza carriers clearly demonstrates that this was due to wide dissemination of B. influenzæ with the progress of the epidemic. Another point of exceeding interest is that the percentage of measles cases carrying B. influenzæ in the throat was lowest during the acute stage of the disease and increased during convalescence. This is in direct contrast with the results found in cases of influenza where the number of cases carrying B. influenzæ in the throat was highest during the acute stage and rapidly diminished in uncomplicated cases with the onset of convalescence.
Summary.—Multiple cultures made simultaneously from the nose, throat and lower respiratory tract showed that B. influenzæ was invariably present in all cases of influenza from the onset of the disease. Not only was B. influenzæ present in all cases, but it was frequently present in predominant numbers, sometimes in nearly pure culture. In the majority of cases that went on to rapid recovery without the development of an extensive bronchitis or complicating pneumonia, the predominance of B. influenzæ over other organisms rapidly diminished coincident with onset of convalescence. Many cases, however, continued to carry B. influenzæ in large numbers in the throat throughout convalescence. No data on the possible duration of the carrier state have been obtained. By the culture methods employed no other organism has been found that would suggest any etiologic relationship to the disease. The two organisms most frequently associated with B. influenzæ in postinfluenzal pneumonias, pneumococcus and S. hemolyticus, have not differed in their incidence in early uncomplicated cases of influenza from that found in normal individuals.
The incidence of B. influenzæ in normal men, in different groups studied, has varied between 11.1 and 88 per cent. This wide variation has depended upon the prevalence of respiratory diseases, more particularly influenza, in the groups studied and the opportunity thereby offered for the wide dissemination of B. influenza. With the progress of the epidemic, the number of normal men carrying B. influenzæ has steadily increased until it reached its maximum at the end of the epidemic.
The incidence of B. influenzæ in cases of measles studied during the epidemic of influenza has been relatively high though never equaling that found in cases of influenza. As in normal men, the incidence in cases of measles has steadily increased during the period of the epidemic. Repeated throat cultures at weekly intervals in cases of measles have shown that approximately 80 per cent became temporary carriers of B. influenzæ at one time or another during the period of the epidemic. Many of these cases had influenza during the time that they were in the hospital. The carrier state in cases of measles was found to bear no relation to the acute stage of the disease since the number of carriers at the time of admission to the hospital was considerably lower than that found during convalescence as determined by repeated cultures in the same cases.
Discussion
The bacteriologic studies in cases of influenza described in this report fully support Pfeiffer’s claim that B. influenzæ is invariably present in the disease. It is particularly important to note that these results were obtained in early uncomplicated cases of influenza and are not dependent upon cultures made from cases complicated by pneumonia or obtained at autopsy. In view of this fact the tendency so apparent in much of the recent literature to relegate B. influenzæ to a place of secondary or minor importance in the disease seems hardly justifiable. It would seem that this tendency is largely dependent upon three factors: first, the failure of many to find B. influenzæ either during life or at autopsy in any considerable proportion of cases; second, the frequent failure to draw a clear distinction between influenza itself and the pneumonia to which it predisposes with a consequent overemphasis upon autopsy bacteriology where a considerable variety of secondary organisms have attracted particular attention; and third, an incorrect interpretation of the undoubtedly large number of B. influenzæ carriers found among normal individuals and those with other diseases during the period of the epidemic and to less extent in interepidemic times.
Since the majority of workers who are thoroughly familiar with the technic of cultivating B. influenzæ have encountered little difficulty in finding it in a large majority of cases, it is felt that the considerable number of negative reports that have appeared can depend only upon the unfamiliarity of those who have failed to find it with the proper bacteriologic methods. This is quite apparent in many of the reports that have been published, and is not surprising in the face of the excessive demand for well-trained bacteriologists occasioned by the war.