SPREADING DISEASE

Northern Advocate, 2 May 1932, Page 3

SPREADING DISEASE

COMMON-SENSE PRECAUTIONS CATARRHAL EPIDEMICS. COMMUNITY ASPECTS. In view of the present epidemic of catarrhal diseases, Dr. Duncan Cook, Medical Officer of Health, has supplied the following’ article on diseases spread "by secretions from the nose and throat. — These diseases are the most prevalent and damaging of the infectious to which flesh is heir. They prevail more particularly in temperate, cool and variable climates, but occur also in warm latitudes and in the tropics. The following diseases are spread in the manner indicated: —Tuberculosis, diphtheria, scarlet fever, measles, german measles, whooping cough, mumps, pneumonia, influenza, common colds, meningitis and infantile paralysis. The actual germ which causes some of those complaints has not yet been isolated, but in all cases the germ or infecting agent is contained in the nasal or throat discharges.

Human beings contract infectious disease directly or indirectly from other human beings, or from animals. The diseases now under discussion are all peculiar to man and we have no evidence that they affect animals. From a sanitary point of view, therefore, every individual in a community represents a. potential source of infection to others. Were wo confronted only by the necessity of guarding against infection originating in recognised eases of disease, the problem of control would resolve itself simply into one of prompt diagnosis or recognition of cases, and isolation. As it is, however, transmission by recognised cases is growing less and less important, as methods of diagnosis and public health supervision grow in efficiency, and, in an increasing proportion of instances, the ultimate origin of such disease' must be sought in the mild unrecognised eases and the carrier. Thus we can have scarlet fever without a rash, infantile paralysis without paralysis, and it is apparent to everyone that cases such as these can actually spread infection without anyone being aware of it.

At any rate, it is now well known to all medical men that in meningitis, diphtheria, penumonia, scarlet fever, infantile paralysis and a number of other diseases, there is constantly pro sent in all communities a definite percentage of individuals who are themselves for the time being immune, but who harbour and constantly distribute disease-producing germs. Under such circumstances, public health organisation cannot fulfil its function merely by being ready to suppress outbreaks of disease as soon ns the first eases arc recognised. Protection is possible only by so organising community life that the routine contact of individuals with infective materials may bo reduced to the smallest possible extent, and by so influencing the habits, nutrition and knowledge of the community that the average resistance of the population may be maintained at the highest possible level. To this is added innoculative measures of control (to bo discussed later).

“Carrier” Defined. We have frequently referred to “carriers of diseases,” so that it is perhaps advisable to explain exactly what is meant by the term. By the term “carrier” we mean a person who is harbouring a diseaseproducing germ, but who, nevertheless, shows no signs or symptoms of disease. The condition is very common with the diphtheria germ. Several types of “carriers” may bo defined. Convalescent carriers arc thoso who continue to harbour germs during recovery from disease, a matter of 8 to 10 weeks or less. Passive carriers are those who harbour germs without ever having had disease.

Active carriers harbour the germs after complete recovery from disease. Acute carriers harbour the germs for brief periods of time. Chronic or permanent carriers may | harbour germs for months or years. Carriers are found in three groups of diseases.— Intestinal carriers occur with typhoid fever, cholera and dysentery. Oral carriers occur in diphtheria and meningitis, etc. Blood anil tissue carriers occur in malaria. Modes of Infection. In the diseases under discussion we shall be referring to oral carriers only, and it is now proposed to give a short description of the manner in which infective material is spread Germs which are contained in the nasal and throat secretions may be transmitted directly from one person to another by kissing, or exposure tc droplet infection in coughing, speak ing and sneezing. Indirectly infection may spread in a number of ways Most common among children perhaps aie toys, pencils, food, fingers, spoons, handkerchiefs or other objects that have been mouthed first by the infected child and then by a susceptible child.

The following (Inscription by an eminent public health authority illustrates how all infections contained in secretions from the mouth and nose may be transmitted. It also illustrates the importance of education in personal hygiene based upon habits of biological cleanliness.

“Not only is the saliva made use of for a variety of purposes, and numberless articles are for one reason or another placed in the mouth, but for no reason whatever and all unconsciously the lingers are with great frequency raised to the lips or the nose. Who can doubt that, if the mouth and nasal glands secreted indigo the lingers would not be continually stained a deep blue, and who can doubt that if the nasal and month secretions contain the germs of disease

the germs will not be almost as constantly found upon the Ungers.’ All successful commerce is reciprocal, and in this universal trade in human saliva the fingers not only bring foreign secretions to the mouth of their owner, but there exchange thorn for his own and distribute the latter to everything that the hand touches. “The only tariff’ known against this •undesirable form of commerce is that of education of the public in the dangers involved. “Children have. no instinct of cleanliness, and their faces, hands, toys, clothing and everything that thev touch must of necessity be continually daubed with the secretions of the nose and throat.” It is well known that children between the ages of two and eight years are more susceptible to scarlet, fever, diphtheria, measles and whooping cough than at other ages, and it may be that one reason for this is the groat opportunity that is afforded by their habits at these ages for the transfer of the secretions. Infants under two do not mingle freely with one another, and they have more resistance to infectious diseases than older children.

Resistance Powers. So far we have been considering the moans of spread of the germs of disease, but fortunately for mankind there - is another side to the problem which we are discussing, and that is the reaction of the human being to infective material which is so lavishly distributed by all and sundry. The body reacts against germs by producing antibodies, which, if conditions are favourable, ultimately overcome the infecting germ. Infectious disease thus resolves itself into a conflict between the infecting -agent or germ and the community at large. It is perfectly' obvious then, that an epidemic may arise either as a result of increased virulence of the germ or by decreased resistance to its activities as represented by the susceptibility of the population.

Preventive medicine aims at the two parts of the problem—both the germ and the resisting powers of the community. To control the germ, its life history must be understood and the means of spread from one person to another. We have already de scribed the ways by which infection may spread, and this knowledge in the minds of all members of the community should assist to a great extent in the lessening of epidemic, diseases. Children can be trained to keep articles and toys out of their mouths. In the same way adults arc often at fault. How many of us habitually moisten our fingers from the mouth when turning the pages of a book? As a rule such a habit does not bring harm to anyone, but if one is a carrier of disease it is obvious that another person using the same book later may cpiite readily become infected. When one remembers that quite a large proportion of any community are actual carriers of disease, it is cpiite easy to understand how infectious diseases are kept alive in a community.

Prolific. Sources. In the. light of what we have been explaining, the evils of expectoration in the public streets are readily understood. Infection in crowded bedrooms, picture houses, at football matches the race meetings takes place most readily by the method of droplet infection which we have already described. When one sneezes or coughs, unless the mouth is proteccdd, droplets of spray are projected for six feet at least, and quite an amount of this spray reaches the nose and throat of anyone within that distance.

That this is not fantastic was proved by a study of soldiers’ sleeping quarters during the war. The disease under investigation was meningitis. It was found in this particular establishment, after an epidemic of meningitis had occurred, that 20 per cent of all' the inmates were carriers of the germ causing meningitis. All that was necessary to control the epidemic was to separate the beds in the sleeping quarters to a greater distance than they had been before, and to provide better ventilation by opening more windows.

It was also found that an epidemic onlv occurred when the number ot carriers rose to df) per cent of the inmates. The virulence or attacking jiower of the germ was therefore increased by overcrowding- in sleeping quarters with bad ventilation. It is believed that these same factors which we have Just described apply in all the diseases which were mentioned at the beginning of this talk. We have still to discuss the resisting powers of the community at large and to indicate how these can be increased. Artificial protection may be given- against certain diseases by innoenlation. Diphtheria ean be prevented by injection of toxin and antitoxin mixtures. Scarlet fever ean be controlled in the same way. In whooping cough there is evidence of protection by the same method. Any medical practitioner will be 1 able to advise parents as to the ad-

visibility of adopting any of the methods of protection described. Aiding Immunity.

Natural immunity is acquired either by an attack of infectious disease orby receiving small amounts of infective material over a long period of time. A massive dose of infective material will break down the defences of a- comparatively healthy individual. Our atm should be to increase our natural powers of resistance by careful attention to all details of personal hygiene. A clean body, correctly clothed, receiving an adequate and balanced diet, living, working and sleeping in healthy conditions,- and with a reasonable amount of open-air life and exercise, will oiler a higher resisting [lower to infection than one, not so ideally situated. Hmall amounts of infective material received over long periods of time raise the natural resisting powers of the body in exactly the same way as an actual attack of infectious disease. Our aim then should be to understand how infection is transferred from one person to another. This knowledge helps every one of ns to guard against massive doses of infection. The result should be a lessened incidence of infectious disease, and with this should be associated a fall in virulence of all infecting organisms, so that the great epidemics of the past should not trouble us as they have so far done. In conclusion, it should be understood by all that all infectious diseases spread by the secretions from the nose and throat depend upon two factors: Firstly, the infecting agent or germ. Secondly, the resistance to infection possessed by the community. The resisting power of the community can be increased by knowledge of the diseases themselves and their methods of spread, and by attention to personal hygiene, and there is also evidence that the virulence of the germs is lessened when the resisting powers of the community are increased.