INFLUENZA

Ashburton Guardian, Volume 55, Issue 291, 21 September 1935, Page 8

INFLUENZA

TOWARDS ITS CONQUEST.

MODERN RESEARCH. The fust mention of “influenza” in literature was in 1743, when the Italians applied this name to the epidemic then raging in Elurope because they attributed it to the influence of the stars (writes Charles H. Lack in the “Sydney Morning Herald.”)

Between 1743 and 1889 theie were about 15 epidemics in Europe that were described as influenza; but as the symptoms of the disease are not very web defined, we cannot be certain of those diagnoses. Most of out knowledge ol this disease is based on the study of the two latest epidemics that of 18891891 and that of 1918-1920. The 1889 outbreak occurred in the heyday of bacteriological research. 'Leeuwanhoek had invented the compound mioiroscope in the eighteenth century; Pasteur had exploded the spontaneous generation theory of disease in the middle of the nineteenth, and by his work on swine and silk pests and on chicken-cholera,, had shown the relationship of micro-organisms to disease; and Robert Koch, the brilliant German bacteriologist, had evolved his technique for the isolation and 1 cultivation of bacteria. Consequently when the 1889 influenza, epidemic broke out, the finding of the casual organism seemed l to be a simple matter and it was not long before a German named Pfeiffer claimed the honour. Bacillus Found. In 1892 Pfeiffer found a, small bacillus in the throats of a number of influenza patients. By that time the epidemic was abating, and no further investigation was made, it being taken for granted that Pfeiffer’s bacillus was the cause. Now Koch' had laid down lour postulates which he insisted could be ascribed to any given organism. These are (1) that the organism shall be found in all cases; (2) that the organism shall he isolated in pure culture; (3) that the culture shall when injected 1 into a susceptible animal produce the symptoms of the disease; and (4) that the organism shall he discoverable from that infected animal, Pfeiffer had not fulfilled these postulates, so that his claim was unjustifiable. When the next outbreak occurred in the spring of 1918, very few bacteriologists were available to study the disease, hut it was noticed that Pfeiffer’s bacillus was not to be found in the throats of many patients with undoubted influenza. This negatived Koch’s first postulate. It was impossible to test the other postulates because no susceptible animals had been found. The first wave of the 1918 epidemic was a comparatively mild form of the disease, characterised 1 by high lever, pains in tho muscles, and extreme conr tagiousness. By the time the war had ended, however, the study of the disease had become very difficult, for the second and third waves were much more virulent, and the lower resistance of the patients allowed other germs such as those which produce pneumonia to complicate the systems, so that it was hard to tell what was due to the primary influenza and what to secondary invaders.

Japanese Investigation Work. It may be mentioned here, as an instance of the international charactei of scientific research, that the next contribution to this investigation was made by Japanese bacteriologists, and that their findings were correlated with an experiment on Nicaraguan sailors. In 1931 an American named Shope studied swine influenza, which js such a menace to the pig industry around St. Louis. He found a bacillus closely resembling Pfeiffer’s, in the noses of swine with this disease, hut when lie injected a pure culture of this bacillus into healthy swine they did not develop influenza. When he inoculated healthy swine with' the filtered nasal washings from influenzal swine* they did develop a mild' influenza, but when he added the bacilli to the filtered nasal washing a much severer form resulted.. These nasal washings had been passed through a filter fine enough to hold back all known bacteria, yet the filtrate still produced the disease. It was therefore said to contain a viius.From this work it appeared that, m swine, influenza is due to a virus, but the presence of Pfeiffer’s influenza bacillus adds to the severity of the disease.

Sliopc- also found that when lie injected this virus into the muscle or healthy swine they did not develop the disease, but were rendered immune to it. A possible explanation of this is that the virus, when injected into a muscle, does not spread through the body nearly ns rapidly as when injected into a vein, so that the body has more time to manufacture anti-bodies to resist the virus, and these antibodies, once made, are always ready to check a later infection.

In England. The story now shifts to England 1 to the laboratory of Patrick Laidlaw, who had been studying dog distemper. In 1933 Laidlaw found that ferrets, which are very susceptible to distemper, could also be' infected with human influenza, thereby providing for the first time a suitable animal for experimental study. He found that human influenza, hke swine influenza, was caused by a virus, not by Pfeiffer’s bacillus and he was able to fulfil Koch’s postulates. Laidlaw has been knighted for his .very import ant work. Last year Laidlaw and his co-work-ers found that the mouse could ho infected with influenza from the ferret, thereby greatly facilitating further refor not only is the mouse more easily handled and less expensive than the ferret, hut also, among mice influenza does not spread from animal to animal as it does among ferrets. So far Laidlaw has not been able to immunise ferrets in the way in which Shope made swine immune, but he is still working on this problem. That this work is of the very greatest importance may be realised from the fact-

that the 1918-1920 epidemic was responsible for more deaths than the Great War.