GENERAL CONSIDERATION

Before beginning the consideration of the individual diseases enumerated in the title, a review of some of the things which relate to them in common may prevent subsequent repetition. The importance of this group of diseases is realized when one remembers that during the ten years ending in 1922, in a large city such as Chicago, more than one person out of every seven of the population suffered from one of these diseases and one out of every 150 died from one of them. Combined these diseases cause about one-fourth of the deaths among children from one to ten years of age. Not only are they responsible for abundant deaths, but they also leave in those that recover a legacy of permanent damage in the heart, lungs, ears, eyes and other parts of the body. Statistics show that more than one-fifth of the cases of deaf-mutism follow scarlet fever, measles and diphtheria. Chronic diseases of the heart and of the kidneys may be due to earlier attacks of scarlet fever.

The diseases here considered constitute an important part of those which are known as contagious. Contagious diseases are those which are transmitted from one person to others by direct or indirect contact. They are sometimes also designated “communicable diseases.”

CAUSES

Each of these diseases is caused by its own peculiar germ. We may compare the germs causing contagious diseases to seeds of plants. Each variety of seed will produce only the sort of plant from which it came. Each of these diseases is due to the implantation of its own peculiar germ in the body, and except in this way the disease never occurs. Each case thus originates from a previous case of the same sort. The old idea that contagious diseases are caused by sewer gas, bad air, disturbances in the weather or similar things, is now known to be untrue. The germs causing diphtheria, scarlet fever and whooping cough and perhaps measles have been isolated and studied. They are all bacteria, which are very small vegetable organisms. In order to be seen by the human eye, they must be magnified about one thousand times by a microscope.

As seeds must be placed in suitable soil if they are to grow and produce plants, so disease germs must find a suitable soil in the body in order to cause disease.

IMMUNITY AND SUSCEPTIBILITY

If disease germs are received by a person whose body acts as barren soil no disease results, while if they reach a person whose body furnishes suitable soil for growth, disease follows. The former person is said to be immune to the disease. The latter is spoken of as susceptible. It is well known that few persons ever have the same contagious disease twice. One attack renders immune a person who was susceptible. This explains why we have epidemics of contagious diseases. During the epidemic most of the persons in a community who are susceptible contract the disease. At the end of the epidemic most of the suitable soil for the growth of the special germ has been exhausted and the population of the community has become immune to the disease. This causes the epidemic to cease. Another outbreak in the same community of the same disease can only occur when susceptible individuals have again accumulated, i. e., when children have been born and reached a suitable age. Epidemics of contagious diseases are naturally confined largely to children who have grown up after the last epidemic occurred, the older members of the community having been rendered immune by attack of the disease earlier in life. In isolated situations where the germs of contagious diseases are not often introduced persons may reach adult age without ever having been exposed to them. Such adults may then become infected the same as children. In the late world war large numbers of young men from rural communities who had never had the usual contagious diseases were brought together in training camps, and thus furnished fertile soil for many epidemic diseases. In a study of over 30,000 native white children in 14 localities in the United States it was found that at 5 years of age 65% have had measles, 48% whooping cough, 22% chicken pox, 5% scarlet fever, and 3.5% diphtheria. As age advanced the proportions increased until at 15 years of age, 88% have had measles, 77.6% whooping cough, 51% chicken pox, 11.6% scarlet fever, and 8.7% diphtheria. By young adult age most persons have had these diseases which are often spoken of as children’s diseases, but some persons are affected later, some adults at quite advanced age.

HOW NEW CASES ORIGINATE

The germs which cause these diseases are given off and escape from the sick person in various secretions and discharges. This includes discharges from the throat, nose, ears and eyes; pus from abscesses in the neck; sputum or other excretions. The crusts from the skin lesions of chicken pox contain the germs of the disease, but the scales from the skin in measles and scarlet fever do not usually do so. The amount of secretion or discharge required to carry enough germs to cause infection is very minute. When the germs are once located on suitable soil they multiply rapidly and enormous numbers are soon produced from an original few. In originating new cases of disease the secretion from the sick with its germs is deposited on some part of the mucous membrane, or lining of the respiratory tract, as the lining of the nose, throat or larynx; or enters through the mouth, and, being swallowed, lodges in the stomach or intestine. At times the infecting material enters through wounds and injuries of the skin, the intact healthy skin usually forming a perfect protection against infection.

The passage of secretions from the sick person to others is accomplished in numerous ways. Sometimes this is through direct contact between two persons, as in kissing. More often the contact is indirect, the secretion being carried on some object. Anything that is contaminated by secretions may carry them to a second person. A few of the most common carriers, such as hands, clothing, bedding, eating utensils, cups, forks and spoons, toys and pet animals may be mentioned. During forced expiratory efforts, such as coughing, sneezing, hawking, stuttering, loud talking or crying, small particles of secretions from the throat and mouth are thrown into the air in the form of what is known as mouth spray. This may be inhaled by persons who are near and be deposited in the throat or nose. This manner of transferring contagious diseases is not so frequent as the others mentioned, and only occurs at distances of a few feet. Secretions which become dry and pulverized into dust outside the body soon lose their power of infecting. Dust is not of much danger as a means of transferring contagious diseases. Sometimes various foods which are contaminated by disease discharges serve to carry them to well persons, in which case they may be deposited in the throat or pass into the stomach or intestines. This is specially true of milk, which has been responsible for many outbreaks of scarlet fever and diphtheria. The disease germs in the milk do not come from cows, but get into the milk during or after milking from the hands, sputum and other means of contact of the persons who handle the milk.

CARRIERS

In recent years persons who are known as disease carriers have been looked on as important factors in the spread of many contagious diseases. The part they play in diphtheria has been abundantly demonstrated and is important. Carriers in this sense are persons who are well, but who carry about disease germs in their throats or noses. They may have recently passed through mild attacks of the disease whose germs remain for a long time after recovery, or they may have received the germs from sick persons, never having been sick. This condition of carriage may persist a long time, and carriers are especially dangerous because not usually suspected.

COMMON PECULIARITIES

Some common peculiarities of contagious diseases may be mentioned. After exposure a definite period of incubation passes before any symptoms develop; many of these diseases have characteristic skin eruptions; they occur in epidemics, especially in children, and one attack usually protects the individual during life.

PREVENTION

Because of the wide distribution of contagious disease and the large number of deaths caused by them, attempts to prevent their spread have been made from remote times. This has been largely concerned with isolation or quarantine of sick persons. Doubtless these measures have been useful, but that they have largely failed to accomplish what is expected of them is not surprising if we bear in mind that many of these diseases are most contagious early in their course before they are recognized and before quarantine is begun, and if we consider the important part which is played by healthy carriers who are not suspected and go about freely.

An ideal condition would obtain if it were possible to render all children, early in life, immune to these diseases. In vaccination against smallpox we have a measure which has banished smallpox to a large extent and which, if universally employed, would eradicate the disease. Similar vaccination measures are now available for diphtheria and scarlet fever. They are easily carried out, devoid of danger, and rarely cause even slight discomfort. These will be again referred to in discussing the individual diseases.

QUARANTINE AND DISINFECTION

The term quarantine was originally applied to the forty days during which a ship suspected of being infected with a contagious disease was held before those on board were allowed to come into contact with those on shore. In present conditions a better term to use is isolation which varies in length and severity in different diseases. The period of isolation in diphtheria is until the person is free of the germs which cause the disease. As it is possible to cultivate and recognize the diphtheria germs the period of isolation can be accurately determined. At times it is only a few days; at other times it must be extended to weeks or even months. In the case of scarlet fever and diphtheria the attendant who is liable to carry infectious materials is isolated with the patient.

In scarlet fever the isolation is four or five weeks and until all discharges have ceased. Discharges from the nose and ear after scarlet fever are apt to contain the cause of the disease, and so are dangerous. Epidemics of scarlet fever have been started in communities by the coming of a child who still had a running ear following scarlet fever many weeks previously.

The danger of transferring measles is quickly over, and patients may be released after the fever has been absent two or three days.

In chicken pox the separation of all scabs is the measure of the isolation period.

Whooping cough is released when the characteristic paroxyms cease.

If measles or whooping cough appears in a child in a family, other children may be sent from home in hope that they have not been infected. They must not be sent where there are children who may be infected if the disease develops.

In diphtheria and scarlet fever the separation of the sick must be absolute. No communication must be allowed between the sick and well. The patient and attendant should be in a separate building, or in a room which can be shut off from the rest of the house. Nothing should pass from the sick room that is not sterilized at once. All discharges should be collected on pieces of gauze, and these with surgical dressings, portions of food, fruit or other material which the patient may have handled may be placed in paper bags and burned without opening. All sheets, towels, pillow covers and bed clothes should be boiled in water before being washed. The same disinfection should be used for eating utensils. After recovery the patient and attendant should be given a thorough bath in warm water with soap. The hair also is washed. In a clean room fresh clothing is to be put on. After the isolation room is emptied of its occupants all its contents are disinfected as thoroughly as possible. This can be accomplished by boiling everything which can be treated in this way, by burning things which have little value and which cannot be boiled such as books, toys, mattresses and pillows contaminated by secretions, by thoroughly washing with warm water and soap all wood work, floors and furniture, and by thoroughly airing and sunning the bedding. The fumigation which was formerly generally used has been largely discontinued. Much more can be accomplished by washing, painting, and removal of paper and replacing by new. A safe rule is to burn everything which cannot be boiled in water or thoroughly cleansed with warm water and soap. Fresh air and sunshine are most efficient destroyers of germs. Children recently relieved from isolation after diphtheria and especially after scarlet fever should not sleep with well children for a week or two, and should not be kissed.

The disinfection required after measles, whooping cough and chicken pox is limited and consists of thorough airing and sunning.

It is not desirable to confine children with whooping cough. They may be taken out of doors, but must not be allowed to play with well children. Diphtheria carriers may also be allowed to be out of doors provided provision is made for keeping them from well persons. Their eating utensils, toys, etc., must always be treated as are those of persons with active diphtheria.

The closing of schools at the times of outbreaks of the contagious diseases is of doubtful value. It does not prevent contact between the children when at play. Most favorable conditions for dissemination of contagious diseases exist in Sunday schools since children too young to attend school as well as older children are here brought together. If closing of schools is to accomplish any good in controlling contagious diseases it must be combined with separation of the families of children at home, and the prevention of children coming together in picture shows and other places.

It is hardly necessary to state that no child who is acutely sick should be sent to school. So many contagious diseases are impossible of recognition at the beginning that each case of sickness must be considered suspicious until it is shown to be harmless.