CONTROL OF DISEASE

Evening Star, Issue 18336, 25 July 1923, Page 1

CONTROL OF DISEASE

MODERN VIEWS OF INFECTION. VACCINES AND SERUMS THE GREATEST FIELD. In the space of an hour or so (says the ‘Post’) Dr M. H, Watt, Director of the Public Hygiene Division of the Health Department, set but in Fuccinct form while addressing members of tho Wellington City Council’s sanitary staff the modern view of infectious disease and the live great measures now recognised as the most- effective means for (he control of such diseases —viz., sanitation, notification, isolation, disinfection, and vaccine and serum therapy. The earlier views of infectious diseases, said Dr Watt, were that they were essentially filth-homo, tho central idea being that the putrefaction and decay of animal and vegetable matter- gave rise to poisonous vapors which wore 1 carried on the air, and gave rise to various epidemic disorders, and hence that idea gave rise to tho popular horror of bad smells, and (hat idea persisted still in the term “ malaria,,” which, trail-dated, literally meant “bad air,” and as a matter of fact the horror of night air and tho consequent closing of windows did help in keeping away malaria, simply because mosquitoes were kept out. Tho “filth theory” led to a, beneficial direction of efforts towards clean streets and yards, clean houses, and the prevention of overcrowding, the provision of sewerage system?, and the supply of wholesome water. Those wore all matters which were to-day regarded as amongst the primary needs of a community, and their provision had undoubtedly exercised a most favorable effect upon public health generally. The lessened overcrowding, by diminishing the risk of acquiring vermin, reduced the incidence of typhus fever, and the increased cleanliness of houses, yards, and towns, by doing away with the haunts of rats, stamped out plague. Those represented the great triumphs of administrative control of infectious diseases based upon the, “filth theory,” but that sanitation in itself was not enough to prevent (he spread l of certain infections. THE GERM THEORY. The modern views of infectious disease, said Dr Watt, constituted what might be termed the germ theory-—the theory _ that all infectious disease was due to a, living agent (germ, virus micro-organism—call them what one would), which gained access to the body and there lived and multiplied, producing toxins or poisons, which in time overwhelmed the host. The channels by which infection might enter the body were usually grouped underlhe headings of the respiratory tract, the digestive tract, and the and perhaps 90 per cent, of all infections were taken in through the mouth; but each disease had its own favorite portal of entry. Then in pulmonary tuberculosis the initial point of attack was upon the Jung, in enteric fever upon the bowel, in diphtheria, upon tlio throat; but in tetanus, on the other hand, the point of attack was an abrasion or punctured wound of the skin. SYSTEM OF CONTROL.

As a natural corollary of the germ theory a system of control had been gradually built up, based upon four main procedures—notification, isolation, disinfection, and vaccine and serum therapy. Notification was called for where the collected information gained thereby would enable tho source of infection to be discovered more easily than when the information was only partial, and when tho notification of each individual case would make more certain the carrying out of precautionary measures than if the control were left solely -in the hands of tho private practitioner or patient; and the value of notification was exemplified by reference to outbreaks of typhoid, smallpox, scarlet fever, and diphtheria, and in the treatment of tuberculosis. The question of homo isolation as against hospital isolation was briefly discussed, and a general conclusion set out that the isolation hospital was probably more valuable from a curative point of view than from a preventive. DISINFECTION. The nearer to the source at which the routes of the transference of disease germs could be blocked the less risk of tho spread of infection, continued Dr Watt, and accordingly the most successful disinfection was that practised by the bedside of the patient. There were live main routes of infection—the air, as in influenza, cerebro-.spiual meningitis, pneumonia, measles, whooping cough, and common cold, particularly under circumstances of overcrowding and tho close proximity to infected persons; “Fondles,” the theory that germs became attached to furniture, clothing, books, money, the walls of a room, etc., an influence which had been over-estimated in tho past, since it was hardly possible for articles in a room to become infected except by contact; contact infection, by the hands as in typhoid fever, by kissing, or by infected articles, spoons, forks, etc., modern opinion being that contact infection was of prune importance, and outweighed Hie other factors m the spread of disease; infection through food and drink, as in typhoid, diarrhoea, cholera, scarlet fever, tuberculosis ; and infection by insects, enteric fever by the ffy, yellow fever and malaria by the mosquito, plague by the flea, and typhus by the louse. Infection by insects was not of much moment in New Zealand, but was of very considerable importance in tropical countries. Sunlight and dryness were Nature’s disinfectants, and those natural agencies, plus the simple precautions of washing the hands before eating or handling food and of keeping the fingers away from the mouth and nose, would go far in preventing infectious disease. VACCINES AND SEEL-MS. Dr Watt then referred to vaccine and scrum therapy, and in tho prevention and treatment of disease, tho distinction being that m vaccine treatment tho, process was one of active immunisation, while in the latter it was purely passive ; or, in other words, in vaccine therapy the individual was inoculated with the germ nr its products, and his natural defensive forces were stimulated to action, but in serum therapy ho was presented with readymade “antibodies,” so-called anti-toxins —vaccination against smallpox and enteric fever, scrum treatment in cases of diphtheria, tetanus, or pneumonia. Summing up the five great measures of control —sanitation, notification, isolation, disinfection, vaccine and serum therapy— Dr Watt said that the same measures were not equally successful with ail diseases. In some cases sanitation alone Lad stamped out disea.se, and in others sanitation alone Had been to a great extent a failure. Notification, isolation, and disinfection had similarly their uses and limitations. Vaccine and serum therapy offered the greatest field of advance, and it was to those methods of prophylaxis that one must look for the future. Already it seemed that in a. few years there would be in common use against diphtheria a method of protection comparable to that conferred by vaccination in smallpox.