PREVENTIVE MEDICINE

Evening Star, Issue 19198, 15 March 1926, Page 4

PREVENTIVE MEDICINE

CONTROL OF INFECTIOUS DISEASES INTERESTING AND USEFUL TALK BROADCASTED BY DR CHAWSHAW. A very interesting and useful ialk on the control of infectious diseases was broadcasted from the Exhibition Radio Station last week by Dr J. IE (,'rawshaw (Medical Officer of Health, Dunedin). “As a department in charge of the preventive side of medicine,” said Dr Crawshaw, “ we are daily brought into touch with infections diseases, not only in absolutely trying to prevent cases of infectious disease;; happening, hut also, in c ase I hey do happen, in trying to prevent thorn hemming epidemic; and, if an epidemic docs take place, trying to slop the epidemic at tho earliest moment. RUBLIG CO-OPERATION ESSENTIAL.

“In attempting to do these things, it is absolutely essential that we have the fullest co-opcration on the part of the public. My remarks to-night will bo directed chiefly to tho point as to how far the public can help us. In order to he able to grasp the method by which wo act, it is necessary to know something about the symptoms of the various diseases and tho length of the incubation period, it is also necessary to give a definition of the phrase ‘incubation period.’ By it we mean that period, or length of time, which intervenes between the patient getting tho infection and the appearance of symptoms. This period is ushered in, it may be, by a chill, or by what is known in medical parlance as a ‘ rigor.’ Then there is a feeling of general scediness, with headache, possibly sore throat, aching of limbs, and rise of temperature. .Alter this period of incubation, which varies in different diseases, the various specific symptoms, such as rashes, appear, and tho particular, disease can he identified. It might bo mentioned here that most—if not all—infectious diseases arc infections during the incubation period. This, of course, makes the prevention of this class of disease difficult to stop in its inception; and this is a very important matter. Take the ease of a person suffering from smallpox". During the incubation period this disease is highly infections, and a good deal of harm may have been done before the disease has been definitely diagnosed. There may have been innumerable contacts with the original person suffering from smallpox, and ail these contacts are potential spreaders of tho disease. This shows how difficult the problem is. All that wo can do is to treat tho first ease seriously from tho outset, and isolate tho patient and tho contacts until we are sure, one way or tho other, of our diagnosis. MOST COMMON DISEASES.

“ The most common infectious diseases are measles, scarlet lever, inilueuzu, diphtheria, smallpox, chickenpox, typhoid lever, and tuberculosis. All these diseases, with the exception of measles and chicken-pox, arc com-, pulsorily notifiable; that js to say, they must bo notified by the medical attendant- to tho medical oliiccr of health, in cases of epidemics of smallpox, chicken-pox becomes a compulsorily notifiable disease, in passing, i might add that in my personal opinion gonorrhoea and syphilis ought to bo included in tho list of compulsorily notifiable infectious diseases. Other infectious diseases, which arc compulsorily 'notifiable but arc not so common, are infantile paralysis (a disease, which, by tho way, we saw a good deal of last year), encephalitis iethargica, and ccrcbro-spinal meningitis. “Measles is a specific infectious fever, with an incubation period generally of nine to twelve days; but the period may be as short as six days or as long as fourteen days. Tho contagion is given off from the secretions of the nose, throat, and lungs, and possibly from tho skin during the whole period of illness. The catarrhal stage preceding eruption is especially infectious. At this stage it is impossible to diagnose the disease with certainty. It is for this reason that epidemics of measles are so difficult to control. Measles is a disease of infancy and early childhood, ft is very fatal to young children, owing to pulmonary complications and sequela?. The mortality of measles is greatest under three years of age. Both sexes arc equally liable to attack. If tho first case of measles could be isolated properly, then a large amount of good could be done. Unfortunately, this ideal cannot always he attained, because, by the time tho disease is definitely diagnosed, there have been a pood many contacts, and so in this way- an epidemic is started. SCARLET FEVER. '' Scarlet fever is a specific infectiousfever, with an incubation period from a few hours to eight clays. It is usually from twenty-four to seventy-two hours. Infection is given off from the throat, and from the skin of the patient, during the whole period of the illness. Tho clothes, bedding, and furniture may carry the infection. Scarlet fever is a disease of childhood, the incidence being greatest at five and six years of age. Tho female sex is more liable to'attack than the male sex, but the attacks in males are more liable to prove fatal. “ Influenza has an incubation period of one to four days. Males are more liable to attack, and to suffer more severely, than females. Personal contact seems necessary for the transmission of tho disease.

“ Diphtheria has an incubation period of four days (two-seven days), and is transmitted probably by ‘ carriers. ’ “The incubation period for smallpox is twelve days. It is highly infectious, and all contacts arc potential transmitters of the disease, which is highly fatal. Vaccination is our sheet-an-chor. Vagrants aro the chief offenders in carrying the disease. “ Chicken-pox has an incubation period of thirteen to nineteen days. It is a mild disease.

“The incubation periof of typhoid fever is ten to fourteen days. ‘ Carriers ’ are probably responsible tor the maintenance of tho disease. Flics are undoubtedly responsible for this type of disease. Therefore, ‘swat that fly.’ TUBERCULOSIS. “ Tuberculosis is a disease to which all warm-blooded animals appear to be susceptible. Tho offspring of phthisical parents appear to be born with a certain degree of susceptibility of_tissue to attack by tubercle. For this reason tho disease was at one time believed to bo directly transmissible by tho parent to tho offspring. This _ has, however, been proved to be a negligible quantity. Tubercular cows can Transmit the disease thorugh their milk to human beings. It is, therefore, essential that the milk we consume should come from a proved non-tubcrenlous stock. All herds of cows should be thoroughly examined and tested in order to prove that the individual cows arc healthy and non-tuberculous.” INSTRUCTIONS FOR THE PUBLIC. Dr Crawshaw gave the following general instructions for the public : “ (1) Carry out in their entirety the inof sickness, pending the araival of a structions issued by the Health Departmont with regard to infectious diseases; (2) carry out all of tho instructions issued by the medical man in charge of the case; (3) in all cases of sickness, spending the arrival of a doctor, it would bo advisable to isolate the patient. “If, ho said, in conclusion, “ these points of instruction arc carried out, the public will bo doing their best, because each one is issued with the object of preventing the spread of the disease.”

RATES OF GROWTH CALIFOfM REDWOOD COMPARED WITH PINUS INSI.GNJS. The following comparative table, allowing the diil’erencea in rate_ ol growth' and in value between Californian redwood trees and pinns insignis, both grown in New Zealand, is compiled from Government official figures— New Zealand Slate Forest Service circular No. d, ‘ Tho Renin rkahlo Pino,’ and ‘Statistical Growth vSiudy,’ by Messrs Whitehnrn and Peggs, Auckland conservation region, 1924: CALIFORNIAN REDWOOD.

Tile late Sir David Hitehins, in his ‘New Zealand Forestry,’ Part L, stated;—“Californian redwood, where it grows well, surpasses every tree now in Now Zealand, either native or introduced.” Californian redwood, indeed, is reputed to be the most valuable softwood tree in the. world, on account of its rapid growth, durability, freedom from attack by insects, ancj its consequent high market value. It is practically indestructible by fire, and possesses an extraordinary capacity for reproducing itself, just as gum trees do, from fiio stump when the original tree is cut down. Redwood soils to-day in the New Zealand market at prices oven higher than first-class kauri or totara. Specimens of redwood timber grown in the Dunedin Botanical Gardens, also small redwood saplings, and a fine model cottage built of redwood, can he seen in the New Zealand Secondary Industries Court.

il Yield Per Present Market Aero Value at 15s (Years). (Super, ft). on Stump. 21 58,197 £436 9 0 30 11S.080 885 10 0 36 157,305 1,179 15 0 PINUS INSIGNJS. 18 30,960 £85 2 0 30 61.920 170 4 0 46 156,250 429 13 0