OUR BABIES

Dominion, Volume 10, Issue 2932, 18 November 1916, Page 14

OUR BABIES

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Published under the <LUspie«B of tho Hoyol Xew Zealand Socicty for the Health of "Women and Children. "It is wiser to put a fence at the top of a precipico than to maintain an ambulanco at the bottom/' INFANTILE PARALYSIS. The Nature, Manner of Conveyance, and Means of Prevention of Infantile Paralysis. • (Continued from the Rockefeller Reaort commenced last week.) Resistance of tho'Virus. The physical properties of tlie virus of infantile paralysis adapt it well for conveyance to the nose and throat. Being contained in their secretions, it is readily distributed by coughing, sneezing, kissing, and by means of fingers and articles contaminated with these secretions, as well' as witli the intestinal discharges. Moreover, as the virus is thrown off from the body mingled with tho secretions, it withstands for a long time even the highest summer temperatures, complete drying, and even the action of weak chemicals, such as glycerine and carbolic acid, which destrpv ordinary bacteria. Hence merit drying of the secretions is no protection; on the contrary, as the dried secretions may be converted into dust, which is breathed into the nose and throat, they become a potential source of infection. The survival of the virus in the secretions is favoured by weak daylight and darkness, and hindered by bright daylight and sunshine. It is readily destroyed by exposure to sunlight. Conveyance by Insects. Since epidemics of infantile paralysis always arise during the period of warm or summer weather, they liave been thought of as possibly being connected with or dependent on insect life./ The blood sacking-' insects nun- especially come under suspicion. Experiments have been, made with biting-tlies, bedbugs, mosquitoes, and with lice. Neither mosquitoes nor lico seem able to take the vims frm tho Wood of infected monkey.i or to retain it lor a time in a living state. In one instance bedbugs have been made to take up tho virus irom the blood of monkeys, 'but. they did not convey it by biting to healthy monkeys. Certain experiments did indicate that the biting stable Ily could both withdraw the virus from the blood of infected and reconvey it to the blood of healthy monkeys, which Tiecamo paralysed. But more recent studies have failed to confirm the earlier ones. Moreover, experimentally inoculated monkeys differ in one way from human, beings sufferings from infantile paralysis for while tho virus may appear in tho blood of the former, it has never been detected in the blood of the latter. The ordinary or domestic ily may becomn contaminated with the virus contained in tho secretions of the body and serve as the agent of its transportation to persons and to food witli which they coma into contact. Domestic.flies experimentally contaminated with the virus remain infective for IS hours or longer. While our present knowledge excludes Insects from being active agents in the dissemination of infantile paralysis, they nevertheless fall under suspicion as being potential mechanical carriers of the virus of that disease. Conveyance by Domestic Animals. The attention which the recent epidemic of infantile paralysis lias dirnwn to the diseases attended by paralysis has led to tho discovery that domestic animals and pets are subject to parlytic disease. Tho animals which liave especially come under suspicion as possibly distributing tho germ of infantile paralysis are poultry, pigs, dogs, and cats. But in isolated instances sheep, cattle, and even horses have been suspected. All these kinds of animals are subject to diseases in which | paralysis of the legs and other parts of the body sometimes' appears. In not a few instances paralytic diseases among poultry or pigs have been noted to coincide with the appearance of cases of infantile paralysis oil a farm or in a community. Experimental studies have, however excluded the above-mentioned animals from being carriers of the virus of infantile paralysis. The paralytic diseases front which they suffer have long been known 1 ", and are quite different from infantile paralysis. Their occurrence may bo coincidental; in no instance investigated has one. been found to be responsible for the other. Routes of Travel. Studies carried out in various countries in which infantile paralysis has been epidemic all indicate that in extending frOm place to place or point to point, tho route taken i:s that of ordinary travel. This is equally true whether the route is by water or land, along a simple highway or tho line of a railroad. In other words, the evidence derived from this class of studies confirms the evidence obtained from other sources in connecting the distributing agency intimately with human beings and their activities. Survival of the Virus 111 the Infected Body. The virus of infantile paralysis is destroyed in the interior, of the body more quickly and completely than, in sotno instances, in the mucous membrane of the nose and throat. It has been found in monkeys, in which accurate experiments can bo carried out, that tho virus may disappear from the brain and spinal cord within a few days to three weeks after the appearance of the paralysis, while at the eamo time it is still present upon the mucous membrane mentioned. The longest psribd after inoculntion in which the virus has been detected in the mucous membrane of the nose and throat of monkeys is six months. It is far mcro difficult to detect the human than the monkey carriers' of tho virus, eiiice, as directly obtained from human beings, the virus'displays a low degree of infectivity for monkeys; wjiile once adapted to monkeys, the virus becomes incredibly active, so that minute quantities are capable of ready detection by inoculation tests. Yet ill an undoubted instance of tho human disease the virus was detected in the m unions membrane of the throat' live months after its acute onset. Hence we possess conclusive evidence of the occurrence of occasional chronic human carriers of the virus of infantile paralysis. Fluctuation in Epidemics. Not nil epidemics of infantile paralysis are equally severe. Indeed, great variations or fluctuations are known to occur not only hi the number of cases, but also in the death-rate, The extremes are reprsented by the occasional instances of infantile paralysis known in every considerable community, and from which no extension takes placc, and the instances in which in a few days or weeks the number of cases rises by leaps and bounds into the hundreds, and the deathrate Teaches 20 per cent, or more ctf those attacked. "While all the factors which determine this discrepancy are not known, certain of them liave become nppnrcnt. A factor of high importance is the infective power or potency, or, technically stated, the virulence of the micro-organism or virus causing the disease. The virus is subject to fluctuations of intensity. . • • Another, but more indefinite factor, relates to. the degree of susceptibility among children and others affected which at one period may be "renter or less than at i another. ° Next week we shall continue the report jf the Eockefeller Institute.