AUGUST, 1916 THE CONTROL OF INFANTILE PARALYSIS With so many cases of infantile paralysis in the City of New York it is inevitable that the disease should spread to the State to a greater or less extent, and also that the territory immediately adjoining the city should bear the brunt of the invasion. If it had been thought advisable and practicable for the rest of the State to quarantine against young children coming from New York City early in the course of the outbreak in the Borough of Brooklyn there can be little doubt that fewer cases would have developed outside of the City of New York. Such a quarantine, however, would have entailed the greatest hardship and been unwarranted, while the machinery for rendering it effective would have been immensely cumbersome and difficult to put into effect. It, therefore, remains for the health authorities of each municipality to take such action in cooperation with the State Department of Health as they deem necessary. While the lack of complete uniformity in local regulations has caused considerable confusion and annoyance in some few instances to persons coming to the various rural communities from the City of New York, yet no instance has been brought to the attention of the State Department of Health where a local board of health has exceeded the powers granted to it by the provisions of the Public Health Law. Until very recently the State Department of Health has been seriously handicapped in its endeavors to control the disease by the small number of Sanitary Supervisors provided for in the last legislative budget, which was still further reduced by the illness of one and the departure for military duty of two others. Through the recent wise action of Governor Whitman in providing an emergency fund to be expended as needed for the services of additional Sanitary Supervisors, diagnostic experts and supervising nurses, this handicap to more efficient service has been happily removed. A disease which presents such protean manifestations as infantile paralysis is often difficult to accurately diagnose even by experts, and the control, therefore, becomes the more difficult. At the present time it is not possible to predict the extent of the dissemination of the disease throughout the State, but it may be said that except in a few localities there has been but little extension from the various cases originating in the City of New York. This has been due to the vigorous action of local authorities in enforcing immediate quarantine of cases and contacts, as well as to the campaign of education which is being conducted throughout the State. The Commissioner of Health desires at this time to express his deep appreciation of the hearty support that he has received, not only from the administrative staff of the Department and the local health officers, but also from private physicians, railroad officials and the press throughout the State. THE NATURE, MANNER OF CONVEYANCE AND MEANS OF PREVENTION OF INFANTILE PARALYSIS* SIMON FLEXNER, M.D. Director of Laboratories, Rockefeller Institute for Medical Research The Rockefeller Institute for Medical Research has been appealed to by so many physicians and laymen for information and advice on the subject of infantile paralysis, that it has seemed desirable to relate the facts of present knowledge concerning certain highly pertinent aspects of the disease, together with deductions of practical importance derived from them. Nature Infantile paralysis is an infectious and communicable disease which is caused by the invasion of the central nervous organs the spinal cord and brain of a minute, filterable microorganism which has now been secured in artificial culture and as such is distinctly visible under the higher powers of the microscope. Location of the microorganism or virus in the sick The virus of infantile paralysis, as the microorganism causing it is termed, exists constantly in the central nervous organs and upon the mucous membrane of the nose and throat and of the intestines in persons suffering from the disease; it occurs less frequently in the other internal organs, and it has not been detected in the general circulating blood of patients. Location of the virus in healthy persons Although the microorganism of infantile paralysis is now known, the difficulties attending its artificial cultivation and identification under the microscope are such as to make futile the employment of ordinary bacteriological tests for its detection. Nevertheless, the virus can be detected by inoculation tests upon monkeys, which animals develop a disease corresponding to infantile paralysis in human beings. In this manner the fact has been determined that the mucous membrane of the nose and throat of healthy persons who have been in intimate contact with acute cases of infantile paralysis may become contaminated with the virus, and that such contaminated persons, without falling ill themselves, may convey the infection to other persons, chiefly children, who develop the disease. Relation of virus to types of the disease The virus has, apparently, an identical distribution irrespective of the Substance of an address before New York Academy of Medicine July 13, 1916 types or severity of cases of infantile paralysis. Whether the cases correspond with the so-called abortive forms of the disease in which definite paralysis of the muscles does not occur at all, or is so slight and fleeting as often to escape detection; whether they correspond with the meningeal forms in which the symptoms resemble those of acute meningitis with which muscular paralysis may or may not be associated; or whether they consist of the familiar paralytic condition, the virus is present not only within the nervous organs, but also upon the mucous membranes of the nose, throat and intestines. Escape of the virus from the body Microorganisms which convey disease escape from the body of an infected individual in a manner enabling them to enter and multiply within fresh or uninfected individuals in such a manner as to cause further disease. The virus of infantile paralysis is known to leave the infected human body in the secretions of the nose, throat, and intestines. It also escapes from contaminated healthy persons in the secretions of the nose and throat. Whether it ever leaves the infected body in other ways is unknown. At one time certain experiments seemed to show that biting insects and particularly the stable fly might withdraw the virus from the blood of infected persons and inoculate it into the blood of healthy persons. But as the virus has never been detected in the blood of human beings and later experiments with the stable fly have not confirmed the earlier ones, this means of escape of the virus must be considered doubtful. On the other hand, it has been shown by experiments on animals, so that the same facts should be regarded as applicable to human beings, that the virus seeks to escape from the body by way of the nose and throat, not only when inoculation takes place through these membranes, but also when the inoculation is experimentally made into the abdominal cavity, the blood, or the brain itself. From this it is concluded that the usual means of escape of the virus is by way of the ordinary secretions of the nose and throat and, after swallowing these, with the discharges of the intestines. Entrance of the virus into the body The virus enters the body, as a rule if not exclusively, by way of the mucous membrane of the nose and throat. Having gained entrance to those easily accessible parts of the body, multiplication of the virus occurs. there, after which it penetrates to the brain and spinal cord by way of the lymphatic channels which connect the upper nasal membrane with the interior of the skull. Whether the virus ever enters the body in any other way is unknown. Certain experiments already alluded to make it possible that it may be inoculated into the blood by insects, and other experiments have shown that under peculiar and extraordinary conditions, it may in monkeys enter through the intestines. But while the latter two modes of infection may operate sometimes, observations upon human cases of infantile paralysis and upon animals all indicate that the main avenue of entrance of the virus into the body is by way of the upper respiratory mucous membrane that is, the membrane of the nose and throat. Resistance of the virus The physical properties of the virus of infantile paralysis adapt it well for conveyance to the nose and throat. Being contained in their secretions, it is readily distributed by coughing, sneezing, kissing, and by means of fingers and articles contaminated with these secretions, as well as with the intestinal discharges. Moreover, as the virus is thrown off from the body mingled with the secretions, it withstands for a long time even the highest summer temperatures, complete drying, and even the action of weak chemicals, such as glycerin and carbolic acid, which destroy ordinary bacteria. Hence mere drying of the secretions is no protection; on the contrary as the dried secretions may be converted into dust which is breathed into the nose and throat, they become a potential source of infection. The survival of the virus in the secretions is favored by weak daylight and darkness, and hindered by bright daylight and sunshine. It is readily destroyed by exposure to sunlight. Conveyance by insects Since epidemics of infantile paralysis always arise during the period of warm or summer weather, they have been thought of as possibly being connected with or dependent on insect life. The blood-sucking insects have especially come under suspicion. Experiments have been made with biting flies, bed-bugs, mosquitoes, and with lice. Neither mosquitoes nor lice seem able to take the virus from the blood of infected monkeys or to retain it for a time in a living state. In one instance, bed-bugs have been made to take up the virus from the blood of monkeys, but they did not convey it to healthy monkeys by biting. Certain experiments did indicate that the biting stable fly could both withdraw the virus from the blood of infected and reconvey it to the blood of healthy monkeys, which became paralyzed. But more recent studies have failed to confirm the earlier ones. Moreover, experimentally inoculated monkeys differ in one way from human beings suffering from infantile paralysis, for while the virus may appear in the blood of the former, it has never been detected in the blood of the latter. The ordinary or domestic fly may become contaminated with the virus contained in the secretions of the body and serve as the agent of its transportation to persons and to food with which they come into contact. Domestic flies experimentally contaminated with |