Staphylococci have scant tendency to enter the blood and have been obtained from the blood of the heart only once, in this instance with hemolytic streptococci.
Pneumonia of Measles.—Pneumonia following measles has been responsible for a considerable part of the deaths occurring in the United States Army during the period of the war. The importance of measles as a factor in the production of pneumonia is illustrated by the history of pneumonia at Camp Funston from the establishment of the camp in September, 1917, until September, 1918. Pneumonia following measles occurred throughout the year; but in association with the high incidence of measles during the second half of November and the first half of December, 1917, there was an outbreak of related pneumonia characterized by frequent empyema and a mortality of 45.3 per cent.
During the period of our investigation at Camp Funston there were 112 cases of measles, but no pneumonia occurred among them. At Camp Pike, during the period of observation, there was an outbreak of measles almost coincident with the epidemic of influenza, and among 867 cases pneumonia occurred in 56, otitis media in 48, and mastoiditis in 23. Pneumonia following measles was almost coincident with that of influenza, and it is not improbable that the epidemic of influenza had an important part in the production of pneumonia in individuals suffering with measles.
In 9 of 56 instances of pneumonia following measles at Camp Pike, S. hemolyticus had invaded the lung and caused pneumonia; among 48 instances of otitis media following measles a very large proportion were caused by hemolytic streptococci, and 21 of 23 instances of mastoiditis were caused by the same microorganism. No complication caused by S. hemolyticus occurred among 37 patients who carried this microorganism when admitted to the hospital.
A special study has been made to determine if those patients with measles who carry S. hemolyticus in their throats are especially susceptible to complications during the course of measles. The low incidence of streptococcus “carriers” among those admitted to the hospitals with measles was noteworthy both at Camp Funston (2.67 per cent) and at Camp Pike (4.2 per cent). Indeed, it was found at both places that the incidence of hemolytic streptococci in the throats of normal men in the camp was higher (Camp Funston 21.9 per cent; Camp Pike 7.4 per cent) than that in the throats of those admitted with measles. While in the hospital there was a gradual increase of the incidence of S. hemolyticus, so that in three weeks it had risen to 19 per cent at Camp Funston and to 26.2 per cent at Camp Pike. It seems not improbable that hemolytic streptococci disappear from the throat in the early stages of measles, so that they are not demonstrable by cultural methods. During the course of the disease in the hospital ward the number of those with S. hemolyticus has increased in some wards with great rapidity, infection being apparently transmitted from one individual to those adjacent. At Camp Funston the incidence of S. hemolyticus in the throats of those convalescent with measles was almost identical with that among normal men in organizations from which the patients had come, but at Camp Funston the percentage of hemolytic “carriers” among convalescents was much higher than that obtained among normal men in the camp.
The demonstration of S. hemolyticus in the throat of a patient suffering with pneumonia is not conclusive proof that the lungs have been invaded by this microorganism. Pneumonia in individuals carrying S. hemolyticus in the throat may pursue a favorable course and exhibit no evidence that the microorganism has found its way into the lung. In some instances hemolytic streptococci have been found in the bronchi at autopsy yet none have entered the lung or blood and the lung exhibits none of the lesions which are referable to hemolytic streptococci. Nevertheless, the occurrence of S. hemolyticus in cultures from the throat of a patient with pneumonia suggests the probability that he is suffering with streptococcus pneumonia.
Pneumonia following measles studied in 18 autopsies upon patients who died during or shortly after the epidemic of influenza, exhibited all the characters exhibited by the pneumonias of influenza. In 4 instances there was typical lobar pneumonia; bronchopneumonia was found in all but 3 instances, being associated with lobar pneumonia twice. All the noteworthy features of the bronchopneumonia of influenza have been reproduced among these instances of pneumonia with measles; there is severe injury to the bronchi, and purulent bronchitis has been present in 13 instances; pneumonia has frequently had a hemorrhagic character, hemorrhagic peribronchiolar pneumonia occurring in 5 instances; secondary infection of the pneumonic lungs with hemolytic streptococci has been common; bronchiectasis has been associated with bronchitis (in 8 instances) when purulent bronchitis has persisted several weeks; and unresolved bronchopneumonia has been more frequent (6 instances or one-third of the autopsies) than with influenza.
The bacteriology of pneumonia following measles has been the same as that of influenzal pneumonia. B. influenzæ is found with few exceptions in the bronchi and much less frequently in the pneumonic lungs.
Pneumococci have been obtained from the blood or lungs in 5 of 13 instances of lobar or bronchopneumonia unaccompanied by suppuration; when suppuration has been absent no hemolytic streptococci have been found. Pneumococci concerned in the production of pneumonia of measles, as with influenzal pneumonia, have been types usually found in the mouth; Pneumococcus II atypical has been found 6 times, Type IV once, Type I once.
Hemolytic streptococci have invaded the pneumonic lung in 5 instances. They have produced subpleural abscesses accompanied by empyema in 2 instances. Interstitial suppurative pneumonia, a lesion repeatedly found in consequence of secondary infection with S. hemolyticus following influenza and rarely found in this country, at least in the absence of an epidemic of influenza, has occurred 3 times among 18 instances of pneumonia following measles.