QUESTIONS ON Tb

New Zealand Listener, Volume 35, Issue 894, 21 September 1956, Page 24

QUESTIONS ON Tb

This is the text of a talk on | health broadcast recently from ZB, YA and YZ stations of the |

ii NZBS by DR.

H. B.

TURBOTT

Deputy Director General of Health

CORRESPONDENT asks further questions about tuberculosis. The first is, "What stages does the Mantoux injection go through, and why is it given?" Mantoux is the name widely used for the tuberculin test, though, in reality, it is the name for a particular form of that test. This doesn’t matter, for this form of tuberculin testing is almost universally used nowadays, and it is common to speak of a "Mantoux test" as synonymous with "tuberculin test." What is this tuberculin test? It is the injection, not underneath, but into the skin of the forearm of a tiny quantity of a substance called tuberculin, This is obtained from killed tuberculosis germs. If we are harbouring tuberculosis germs anywhere in our bodies, we object to having this tuberculin substance put into our skin. We have become sensitive to tuberculin because of the germs within us. We show this sensitivity by an allergic type of reaction, a small red swollen area surrounding the point of injection becoming obvious within two to three days. The test is said to be positive when this happens. If the skin does not become red and swollen, the test is negative, and this means that there has been no contact with the germ that causes tuberculosis. A positive test indicates that some resistance to tuberculosis is built up in the body from some previous contact with it. This is all that a positive test means, that you have met and received some tuberculosis infection at some

period in your life. Now we are presented with a problem! Arte those germs which we acquired some where, sometime, overcome and dead and sealed off? Or are they active and working within the body? In the very rare person there is activity, but in the majority the positive test medns victory, the battle is over, and having learnt how to over-

come the germs, we afe all the stronger to meet them in the future. This, of course, is the basis of B.C.G. vaccination of those with negative tuberculin tests. In a sure but harmless way we are turning negatives into positives, teaching bodies to meet and conquer the Tb germ, But to return to our problem. How, being positive to the tuberculin test, can we be sure the germs within us are beaten and inactive, and are not working up the disease within us? Simply by having an X-ray to exclude the possibility of tuberculous disease. The vast majority with a positive test have a clear X-ray. This tuberculin test is of great value in the war against tuberculosis. If you throw a negative, you can proceed to B.C.G. vaccination to be strengthened against Tb germs in the future. If you throw a positive, you have an X-ray to make sure you have won the battle, or to reveal, should you be the odd unlucky one, the presence of activity, while early, so that cure can. be accomplished smoothly and

quickly. The tuberculin test is the guide as to whether vaccination or an X-ray is needed, and the revealer of the extent of tuberculosis infection in a community. Now for the second question! "What ig meant by a ‘carrier’? Can we carry the disease and yet have no symptoms?" It is not customary to talk of "carriers" of tuberculosis, but to classify tuberculous sufferers as active, or inactive, or quiescent. Activity means that Tb germs are probably being given off in the sputum, and the sufferer must learn those safeguarding precautions that protect others from infection while, he is winning the fight. Such, a person could be a carrier of infection to others, if thoughtless and -careless. When the disease is healing, is quiescent, or inactive, the chances are that Tb germs are not being given off. In fact, the majority of cases of tuberculosis, about 66 per cent are no danger to others. Can one have tuberculosis disease and show no symptoms? ‘When ‘there is active disease symptoms do reveal themselves... Unfortunately, the disease sometimes gets a good hold before this revealing happens, in symptoms such as persistent tiredness, steadily getting thinner, a recurrent catch in the throat or cough, pleurisy or pain in the chest,

breathiessness on exertion, bloodstained spit, profuse sweating at hight. The person who-has actual tuberculous disease will have at some stage one or more of these symptoms. They may be missed, they may be late in revealing themselves. Coughs are often taken too lightly. Any person with a cough for for than one month should have a chest X-ray. .