Comparison of cases of illness during the summer of 1913 in two city blocks, one clean and the other dirty. What are your conclusions?
The Division of Infectious Diseases.—Infectious diseases are chiefly spread through personal contact. It is the duty of a government to prevent a person having such a disease from spreading it broadcast among his neighbors. This can be done by quarantine or isolation of the person having the disease. So the board of health at once isolates any case of disease which may be communicated from one person to another. No one save the doctor or nurse should enter the room of the person quarantined. After the disease has run its course, the clothing, bedding, etc., in the sick room is fumigated. This is usually done by the board of health. Formaldehyde in the form of candles for burning or in a liquid form is a good disinfectant. In disinfecting the room should be tightly closed to prevent the escape of the gas used, as the object of the disinfection is to kill all the disease germs left in the room. In some cases of infectious disease, as scarlet fever, it is found best to isolate the patients in a hospital used for that purpose. Examples of the most infectious diseases are measles, scarlet fever, whooping cough, and diphtheria.
Immunity.—In the prevention of germ diseases we must fight the germ by attacking the parasites directly with poisons that will kill them (such poisons are called germicides or disinfectants), and we must strive to make the persons coming in contact with the disease unlikely to take it. This insusceptibility or immunity may be either natural or acquired. Natural immunity seems to be in the constitution of a person, and may be inherited. Immunity may be acquired by means of such treatment as the antitoxin treatment for diphtheria. This treatment, as the name denotes, is a method of neutralizing the poison (toxin) caused by the bacteria in the system. It was discovered a few years ago by a German, Von Behring, that the serum of the blood of an animal immune to diphtheria is capable of neutralizing the poison produced by the diphtheria-causing bacteria. Horses are rendered immune by giving them the diphtheria toxin in gradually increasing doses. The serum of the blood of these horses is then used to inoculate the patient suffering from or exposed to diphtheria, and thus the disease is checked or prevented altogether by the antitoxin injected into the blood. The laboratories of the board of health prepare this antitoxin and supply it fresh for public use.
Antitoxin for diphtheria prepared by the New York Board of Health.
It has been found from experience in hospitals that deaths from diphtheria are largely preventable by early use of antitoxin. When antitoxin was used on the first day of the disease no deaths took place. If not used until the second day, 5 deaths occurred in every hundred cases, on the third day 11 deaths, on the 4th day 19 deaths, and on the 5th day 20 deaths out of every hundred cases. It is therefore advisable, in a suspected case of diphtheria, to have antitoxin used at once to prevent serious results.
Vaccination.—Smallpox was once the most feared disease in this country; 95 per cent of all people suffered from it. As late as 1898, over 50,000 persons lost their lives annually in Russia from this disease. It is probably not caused by bacteria, but by a tiny animal parasite. Smallpox has been brought under absolute control by vaccination,—the inoculation of man with the substance (called virus) which causes cowpox in a cow. Cowpox is like a mild form of smallpox, and the introduction of this virus gives complete immunity to smallpox for several years after vaccination. This immunity is caused by the formation of a germicidal substance in the blood, due to the introduction of the virus. Another function of the board of health is the preparation and distribution of vaccine (material containing the virus of cowpox).
Rabies (Hydrophobia).—This disease, which is believed to be caused by a protozoan parasite, is communicated from one dog to another in the saliva by biting. In a similar manner it is transferred to man. The great French bacteriologist, Louis Pasteur, discovered a method of treating this disease so that when taken early at the time of the entry of the germ into the body of man, the disease can be prevented. In some large cities (among them New York) the board of health has established a laboratory where free treatment is given to all persons bitten by dogs suspected of having rabies.
Vaccination against Typhoid.—Typhoid fever has within the past five years received a new check from vaccination which has been introduced into our army and which is being used with good effect by the health departments of several large cities.
The following figures show the differences between number of cases and mortality in the army in 1898 during the war with Spain and in 1911 during the concentration of certain of our troops at San Antonio, Texas.