SLEEPY SICKNESS.

Hauraki Plains Gazette, Volume XXXV, Issue 4724, 14 July 1924, Page 1

SLEEPY SICKNESS.

CAUSE AND CUKE. STUDY OF GERMS. (By An Immunisator, in the "Daily Mail.”) It must Xie a great puzzle to tne non-mecUcal mind when there is such an acute difference of opinion between doctors as to the cause of a disease such as encephalitis lethargica, some declaring positively the cause is known, other 'that the causative microbe has never been isolated. The explanation is this. Those who do not believe that the microbe has been discovered found their opinion on the fact that Koch’s Laws of Pathogenicity have not been fulfilled.

Robert Koch laid down that in order to establish a microbe as being pathogenic—that is, disease-producing —firstly, it must be isolated constantly from people suffering from a disease ; secondly, the, microbe must be capable of producing the disease in an animal; and, thirdly, the microbe must be isolated again from the animal so infected.

Very few microbes satisfy Koch’s law, since microbes causing disease hi one animal either do not infect another animal at all or, if they do, seldom reproduce disease of the same kind. .The tubercle bacillus, both the human and the bovine type of it, cause tuberculosis in both human beings and- certain animals and satisfy the law, but even in this ease they do not produce in rabbits and guineapigs exactly the same form as m human beings, for the pulmonary form of tuberculosis cannot be reproduced in all its details in these ani-mals,-because it is always a mixed infection with other microbes in human beings and not in animals, so that for the majority of human infections other criteria of pathogenicity must be sought.

- For instance, certain tests can be applied. Tuberculous infection furnishes again a good example. A bow may be infected with tuberculosis, but. the tissues infected' are not vital organs and are not destroyed to such an extent as to produce symptoms of illness, nor can the microbe be isolated from that animal without killing it, or, if a joint is infected, without operation on it.

If in such an. animal an antigen or vaccine of the tubercle bacillus, commonly called tuberculin, is injected under the skin, the animal “reacts” by getting a rise of temperature and pulse-rate, and increase of inflammation at the site of infection, ivhich can be readily recognised n the case of a joint. Experience has shown that all such cattle so reacting .to tuberculin have active tuberculosis—that is, their tissues are being destroyed by the tubercle bacillus. Moreover, if a series of suitable- doses is continued the animal can be cured. This is Known as therapeutic immunisation. .Reaction after inoculation with the prescribed dosage of antigen (vaccine) made, from* a given microbe i< absolute evidence of a patient being infected with that microbe. This law, which is generally accepted in the case of tuberculosis, has not been : generally , applied to the diagnosis of other obscure infections, but it is qust as significant in such cases, so that in the case of such an infection pf the brain as. encephalitis lethaigica, or sleepy sickness, where it is quite impossible to isolate the infecting microbe during life, if the infected person reacts after the injection of an antigen (vaccine) made from the influenza bacillus in suitable dosage, one knows absolutely that that patient’s brain is infected with that pa'tricular microbe, although the influenza bacillus cannot be isolated from it. The diagnosis is confirmed if by a course of inoculation with this antigen the case is rapidly cured, and still further confirmed if by this treatment in a number of 'cases the deathrate is reduced. A patient with encephalitis lethargies in my experience always reacts to an antigen of the influenza bacillus, and so far, in my hands, the death-rate in a small series ofi cases das been nil. And, further, I know of only one case, a very advanced one that has been ill a long time, in which the inoculation supplied by my laboratory failed to save his life. If, however, the treatment of any infection is .to be effective it is absolutely; essential that the material used for inoculation is potent, otherwise the results- may be disappointing.