Further studies on the etiology of epidemic hiccough.

Abstract

In two previous epidemics I have isolated a streptococcus from infection atria in cases of epidemic hiccough which produced spasms of the diaphragm and other muscles in animals. This property was readily lost on ordinary aerobic cultivation, but by rapid transfer (four to eight times in twenty-four hours). In partial tension cultures, its specific infecting power was maintained through as many as fifty culture generations. Moreover, when the living streptococcus incited spasms of the diaphragm, the washed dead bacteria and filtrate of the actively growing culture also produced this phenomenon. This streptococcus had the power of producing a poison which caused lesions in the cervical cord or in the roots of the phrenic nerve, and provoked spasms of the diaphragm.

In a recent outbreak of another epidemic, I have again isolated this streptococcus. The symptoms in the present epidemic are less severe, more irregular and of shorter duration than those of the two previous epidemics studied. The duration of hiccough in the six cases studied ranged from two to eight days. In five of the six there was an associated infection of the throat, of varying severity. Moderate nasopharyngitis or tonsilitis was found in all. Cultures on blood agar plates of nasopharyngeal swabbings and of pus expressed from tonsils showed an unusually large number of green-producing streptococci, often in almost pure culture. Precipitin tests with nasopharyngeal washings and my poliomyelitis and encephalitis serums were positive in three and negative in three of the cases.

Of the thirty-two animals injected intracerebrally with material from infection atria or partial tension cultures thereof, fifteen were seen to have spasms of the diaphragm; thirteen, of the abdominal muscles, and twenty-three, of other muscles. A total of twenty-eight had spasms of the diaphragm or of other muscles.