INFLUENZA

Evening Star, Issue 22559, 29 January 1937, Page 6

INFLUENZA

ATTACK OR DISEASE In 1932 Dr Thomas M. Rivers, of the Rockefeller Institute, a well-known authority on viruses, had this to say before the American Society of Clinical Medicine in his presidential address (writes the science editor of the ‘ New York Times’): —^ “ Many viruses obtain entrance into their hosts by way of the upper respiratory tract. Our inability to control disorders arising in this manner is not due to the fact that we have not used some special kind of medium for the cultivation of the viruses but because it is essential that we breathe, and as yet no one has suggested a ‘cal method of obtaining uninair for human beings living amongst their fellows.” It may be that this opinion, now four years old, may have to be revised in the light of some experiments which have been conducted by Drs H. W. Brown and W. F. Wells, of the Harvard School of Public Health. They have shown that the virus of influenza can live in air, and that it can be killed by rays from ultra-violet lamps. But whether ultra-violet _ rays are indeed practical in Dr Rivers’s sense, meaning efficient and inexpensive, only further research can reveal. A FILTERABLE VIRUS. Bacteriologists are agreed that influenza is caused by what is called a filterable virus, which is merely a name for something about which very little is known. Whether a filterable virus is a collection of germs too small to be

seen in any microscope or whether iff is a mysterious chemical that becomes virulent when it touches living tissue is still a matter of dispute. It is called “ filterable ” because it can pass through a porcelain strainer so fine that it holds back microscopic bacteria. Medieval medicos thought that the diseases we call contagious were borne by the air. It was so good' a hypothesis that their ‘ successors of the twentieth century still cherish it. Butis it true of influenza? Is so, how; long does influenza virus live in; the air? There are other supposedly ultramicroscopic organisms besides the filterable viruses. Bacteriophage is one—a, name for an invisible • something , that preys, on visible germs. About five years ago Dr Men 6. Colvin, of the Yale University Medical School, showed that bacteriophage can travel through air a distance of 35ft in smin, also that it floated about in the dust of his laboratory for at least 18 days. ..The more thoroughly he swept and xnopped r the more did he find. There is a difference between a filterable virus and bacteriophage. Still Dr Colvin’s work shows that others had been wondering whether invisible microscopic organisms were wafted about in the air. BROWN-WELLS EXPERIMENTS. Drs Brown and Wells have gone a? step further. Can a filterable virus —* to wit, the influenza virus—live when it is thus floating about? They made a series of experiments which covered five years, it is said. One of the most virulent strains of influenza virus is known as Porto Rico 8. Brown and Wells sprayed it into a sealed tank. Next they drew off some of the contaminated tank air and whirled it about in a centrifugal separator devised by Dr Wells. Thus they recovered heavier material which they inoculated into ferrets. ■ Down came the ferrets with the disease. Who could doubt that influnza is carried by the air after that? _ _ Can tho virus be killed in the air?, Another batch of contaminated air was passed through deadly rays from a cold quartz mercury lamp. More centrifuging of the collected air. More inoculations. But the ferrets did not succumb. Whether a forward step has been taken in the conquest of influenza it is too early to decide. But the question naturally arises: If the water, of swimming pools can be effectively treated with ultra-violet rays to kill 1 micro-organisms, why not the air wa breathe? Mercury lamps are cheap to operate. But is the cost so low that! it is possible to irradiate a whole mo-j tion picture theatre with ultra-violet light. It is to be inferred from the account of their work which Drs (Brown and Wells publish in ‘ Science ’ that tho stuff which they collected after whirling contaminated air in a centrifugal separator was inoculated directly into ferrets. Should not some bacteriologist put ferrets in a tankful of contaminated air and see whether they, catch influenza merely by breathing as we do ? THE TWO STAGES. In the study of influenza there havs been two stages. Tho first was concerned with the life and effect of tha bacillus that Peiffer thought he had discovered. By 1918 bacteriologists ceased to believe in it—could not verify; his microscopic studies in fact. Tha second stage was entered with the oonvinction that influenza is caused _ btf an invisible organism or some chemical called a filterable virus. The method of transmitting influenzal is of crucial importance. But thera is no evidence as yet that the disease spreads naturally from infected animals to others living in contact with them. At least that is the verdict expressed in the British Medical Council’s report! for 1933-34. Studies made during the epidemic! of influenza of 1918 are still being quoted. Volunteers were then innoculated with filtrates that came from! sufferers. But experiments in which! volunteers were- exposed to sneezing and coughing influenza victims came to nothing. This does not mean that the influenza virus is not air-borne—-merely that it was impossible to exer< cise the necessary scientific control. Foi one thing, there was no wav of checking or knowing the personal immunity of volunteers..