Is polio contagious?
Let the science speak!
J. R. Paul - “The earliest clinical descriptions of [infantile paralysis] came from several diverse areas: England, 1795; Italy, 1813; India, 1823; and U.S.A., 1830 … There was no mention of contagion, or of epidemics, nor was the condition regarded as a medical problem of any magnitude.”
A. C. Bull, 1868 - “It does not seem apparent in this small [polio] epidemic that contagion played any role, because the disease occurred here and there in the different places of the district without the possibility of establishing any relation between the various cases or the families of the same.”
K. O. Medin, 1887 - “Medin did not consider polio to be a contagious disease.”
C. Caverly, 1894 - “There was a general absence of infectious disease as an etiologic factor in this [polio] epidemic. The element of contagium does not enter into the etiology either. I find but a single instance in which more than one member of a family had the disease, and as it usually occurred in families of more than one child, and as no efforts were made at isolation, it is very certain that it was non-contagious.”
C. B. Leegaard, 1899 - “Infantile paralysis is of an infectious, but not of a contagious nature. As a matter of fact no indisputable instance of contagion could be proved.”
I. Wickman, 1905 - “Pediatrician Ivar Wickman investigated the 1905 [polio] epidemic and visited over 300 cases. The epidemiological picture showed that polio cases often occurred miles apart from each other with no obvious connections.”
The New York Neurological Society, 1907 - “A Collective Investigation Committee of the New York Neurological Society…was appointed to investigate this [polio] epidemic of 1907 … The committee concluded from the returned blanks that poliomyelitis was infectious but not a contagious disease.”
H. C. Emerson, 1908 - “A large number [244] of children were in intimate contact with those that were sick [polio], and of these children an insignificant minority developed the disease.”
J. Zappert, 1908 - “Zappert collected 137 [polio] cases in North Austria ... he failed to prove contagion in this epidemic.”
A. S. Hamilton, 1908 - “Hamilton reported three epidemics of poliomyelitis, all more or less extensive, occurring in Minnesota in 1908 … There was no evidence found that the disease was infectious or contagious.”
L. E. Holt & F. E. Bartlett, 1908 - “We have collected reports of 35 epidemics of poliomyelitis prior to the year 1907 … The comparatively small number and wide distribution of the cases in most of the epidemics is very striking, and seems to indicate that the different cases had no relation to one another or to a common cause … We have taken especial care to secure the data regarding the occurrence of more than one case in a family or household. On this subject we have included not only facts derived from a study of the epidemics here collected, but also other single instances which have been scattered through literature. In all we have collected a total of 40 instances, comprising 96 cases, in which more than 1 case occurred in a family or household … Whether we can go farther and state that the disease is communicable is an open question.”
Massachusetts State Board of Health, 1909 - “Poliomyelitis prevailed in epidemic form in Kansas during the summer of 1909 … No method of contagion could be found, and the author does not consider the disease contagious.”
K. Landsteiner & E. Popper, 1909 - “Attempts to transmit the disease [polio] to the usual laboratory animals, such as rabbits, guinea pigs, or mice, failed.”
E. W. Martin, 1909 - “I do not believe poliomyelitis is contagious.”
S. Flexner & P. Lewis, 1910 - “Many guinea-pigs and rabbits, one horse, two calves, three goats, three pigs, three sheep, six rats, six mice, six dogs, and four cats have had active [polio] virus introduced in the brain but without causing any appreciable effect whatever. These animals have been under observation for many weeks.”
S. Flexner, 1910 - “It was not easy to establish in an individual case precisely how the disease [polio] was acquired; it was difficult to bring evidence that was at all convincing that this disease was contagious … It was necessary to bring the infected material from the human source from the central nervous system and spinal cord in direct relationship with the central nervous system of the monkey … Monkeys did not spontaneously take the disease, and the question naturally arose why a disease which was so fatal in this species should not occur naturally or spontaneously in that species.”
S. Flexner, 1910 - “No instance of the spontaneous transfer of the virus from a paralyzed to a normal monkey arose, although many opportunities for contagion in the course of our many experiments occurred.”
L. E. Holt, 1910 - “Even five years ago if anyone had suggested that the disease under discussion [polio] was an infectious or a contagious one, it would have been looked upon as a joke.”
B. Sachs, 1910 - “So far as the contagiousness of poliomyelitis was concerned, it was a curious fact that in the hospitals where the cases were not thoroughly isolated, other cases had not appeared. He did not know of one family in which there was one case that infected another member of the family”
F. E. Batten, 1911 - “Against the infectivity of the disease may be urged, first, the absence of spread of infection in hospital. The cases of poliomyelitis admitted to hospital freely mixed with other cases in the ward without any isolation or disinfection, some 70 children came in contact, but no infection took place. On these grounds it is probable that the paralytic stage of the disease is not contagious. Secondly, the striking absence of infection when contact has been most close. In November, 1909, H. E. was taken ill with poliomyelitis; all five brothers and sisters, although in closest contact, remained unaffected. In October, 1909, M. K., aged 2½, was taken ill; two sisters, aged 6 and 11 respectively, slept with and were in close contact with the child and remained unaffected. Twin sisters, aged 2½, one was affected, the other unaffected.”
I. Strauss, 1911 - “The material consisted of ten [polio] cases … The mucus was obtained by passing dry cotton swabs into the nasopharynx through the mouth … The filtrate was then centrifuged and either 2 or 4 c.c. were injected intracerebrally into [10] rhesus monkeys … No monkey became ill as a result of these inoculations.”
M. J. Rosenau et al., 1911 - “The material thus collected was injected into the brain and peritoneal cavity of [18] monkeys … These results were negative [see no. 42].”
R. W. Lowett & M. W Richardson, 1911 - “No instances as yet have been reported in which one monkey has taken the disease [polio] from another, although long continued and intimate contact has been maintained.”
Dr. Acker, 1911 - “I have not seen any cases of [polio] contagion. We put the patients on one side and typhoid cases on the other, and no nurse or mother was infected. If the disease was so contagious, I don’t see why the nurses and mothers would not have been infected.”
L. M. Beeman, 1911 - “Two [polio] epidemics in Connecticut studied by one of our ablest and most careful investigators point to the conclusion that in these epidemics contagion was not present.”
H. D. Chapin, 1911 - “There is one aspect of this disease [polio] of considerable interest. Years ago we never thought of contagion with reference to it.”
S. S. Adams, 1911 - “One very large institution in New York reported that it did not take any means whatever to isolate and did not consider the disease [polio] a contagious one. As to the disease originating in the hospital, the invariable reply was, no. That was our experience in the hospital.”
A. B. Soltau, 1911 - “Is poliomyelitis infectious or contagious? That it has been labelled “infective poliomyelitis” is no proof.” […] “It is uncommon to find more than one case in a family, and in none of the Plymouth cases was more than one affected in the same household. Nor…was there any evidence of contagion. Further, it is practically unknown for the disease to spread in hospitals, though no isolation precautions are usually taken.” […] “The proofs, however, of infection by direct contagion, or through the intermediary of “contacts” are scanty.”
Scientific American Supplement, 1912 - “Dr. Manning further points out that the disease is probably not transmitted by ordinary contagion for the following reasons:
1. The experimental production of the disease in monkeys is by inoculation.
[…]
3. Poliomyelitis artificially induced in monkeys has never been spontaneously transmitted to animals confined in the same cage or room.
4. The comparative rarity of multiple cases in families.
5. Acute cases of poliomyelitis introduced in wards of hospitals not followed by a secondary case.”
[…] “It appears, then, that … ordinary contagion, that is to say, transmission by mere contact or proximity of two persons does not occur.”
C. Levaditi & V. Danulesco, 1912 - “As early as 1912, Levaditi and Danulesco reported that normal Rhesus monkeys housed with infected monkeys did not develop poliomyelitis.”
J. J. Moren, 1912 - “Monkeys suffering from polio in the same cage with healthy monkeys, do not infect others. Also, in the majority of cases occurring in an epidemic only one member of a family is affected. In proportion to the number exposed, very few suffer.”
R. M. Hewitt, 1912 - “I submit that the evidence in favour of contact transmission [of polio] is slight. It is not common to find more than one case in a family. It has not been found to spread in hospitals, although isolation precautions were not taken.”
E. M. Mason, 1912 - “The question of [polio] contagion, in the usual sense of the word, is not settled … Healthy monkeys have been kept in cages with others in various stages of the disease, yet no infection has been reported.”
W. H. Frost, 1912 - “As regards the epidemiologic evidence of [polio] contagiousness, it has usually been impossible, even in epidemics, to trace lines of contact from case to case … it is characteristic that the cases are scattered, occurring in persons who have never been in any sort of direct or known indirect contact with a previous recognized case. Not infrequently the patient is a child living far away from the nearest known previous case, and who has certainly not been away from home within a period of several weeks before the attack. Still more striking evidence of the non-contagiousness of poliomyelitis is afforded by the fact that one rarely finds more than a single case in a family, and still more rarely finds multiple cases in a family separated by such an interval as would suggest the infection of one from the other. Numerous instances can be cited where large numbers of children have been exposed in schools or institutions, to acute cases of poliomyelitis without the development of any secondary cases.”
R. Farrar, 1912 - “Attempts to convey the disease [polio] to non-infected monkeys by exposure to contagion from infected monkeys in the same cage have hitherto failed.”
M. J. Rosenau, 1913 - “Careful and masterly epidemiological investigations of poliomyelitis have been conducted by the Massachusetts State Board of Health extending over a period of five years. The results of these studies were summarized by Dr. Mark W. Richardson, who plainly brought out the fact that the disease, as observed in Massachusetts, does not have the earmarks of a contagious disease. The disease prevails in rural rather than under urban conditions. In fact it shows little tendency to invade cities, and when it does enter the city it does not strike the crowded, congested portions of the city.” […] “Cases of infantile paralysis in all stages of the disease have been taken into the hospitals, orphan asylums, children’s homes, reformatory schools, and other institutions in the Commonwealth, but in no instance during the five years in which the disease has been studied has it ever spread under these circumstances.”
P. H. Römer, 1913 - “No proofs of the contagiousness of the disease [polio] could be obtained in the great epidemic in New York in 1907, nor in the epidemic in the Steiermark (Furntratt, Potpeschnigg) nor in Pomerania (Peiper).”
The Lancet, 1913 - “In the Deddington [polio] epidemic…it was apparently impossible to trace any direct contagion, even by the interposition of poliomyelitis carriers.”
W. H. Frost, 1913 - “The statistics presented in this report show that of 2,070 persons exposed to poliomyelitis by residence in the same houses and same families as poliomyelitis patients, only 14 (0.6 per cent) developed the disease.”
A. H. Jennings & W. V. King, 1913, - “Poliomyelitis, moreover, is marked by the occurrence of sporadic cases, not to be explained by contact infection and there is a lack of evidence of direct contagion, two facts which are true of pellagra.”
H. W. Frauenthal & J. VV. Manning, 1914 - “Advocates of the contagion theory were at a loss to account for the fact that spontaneous [polio] transmission among laboratory monkeys was never known to occur.” […] “There is no proof that spontaneous transmission of acute poliomyelitis, without an inoculation wound, can take place. There is no proof that contact contagion takes place. Spontaneous development of the disease among laboratory animals is unknown.”
M. J. Rosenau, 1914 - “Rosenau, Sheppard and Amoss therefore injected 18 monkeys with the nasal and buccal secretions obtained from 18 persons who were suffering with the disease [polio] at the time, or in the stage of convalescence, or from persons suspected of acting as carriers. These results were negative. At the same time Straus of New York had a series of negative results, and other American workers were also unable to find the virus where we assumed it should be. These negative results seemed to us to have positive significance, and was the first definite indication that we were upon the wrong trail. That poliomyelitis is not a “contagious” disease was clearly brought out by Dr. Richardson and other observers who have spoken this morning, all of whom have emphasized the point that the disease shows little or no tendency to spread in crowded districts, in schools, in institutions, in asylums, in camps and in other places where one would expect a disease spread by contact through secretions of the mouth and nose to spread most readily. We have in mind the fact that many cases of the disease have been brought into asylums and hospitals throughout the State of Massachusetts, in all stages of the infection; yet secondary cases have not occurred under such circumstances. On the contrary the disease prevailed in Massachusetts more particularly in rural and country districts sparsely settled.”
M. W. Richardson, 1914 - “The experience of Massachusetts has not been such as to support the theory that infantile paralysis is spread from person to person by direct or indirect contact. The rural preponderance of the disease, the comparative immunity of children confined in institutions and hospitals, the summer incidence, the failure of the disease to find its greatest incidence in cities and localities where density of population and overcrowding are most marked, and the irregular distribution have all militated against the acceptance of such a theory.”
Official Reports of the Bureaus of the Department of Health, 1916 - “No attendant, physician, nurse or domestic, and no patient admitted to any of the hospitals throughout the city, for other cause than poliomyelitis, during the [1916 polio] epidemic, contracted poliomyelitis. This has been the almost universal experience in the past, and has often been brought forward as a proof of the non-communicable character of the disease.”
W. H. Frost, 1916 - “Only a small proportion of cases can be ascribed to known contact with previous definite cases of poliomyelitis. Even including association with merely suspicious cases of illness, the majority of cases of poliomyelitis can not be traced to known contact, either direct or indirect, with any previous case. It is this apparent lack of relation between cases which has led so many investigators to seriously doubt or even deny the transmissibility of the disease.” […] “The disease develops in such a small proportion of persons known to be intimately associated with acute cases. It also seems well established that the recognized cases of the disease must be relatively unimportant sources of infection. This follows necessarily, because a large proportion of the cases studied have been in persons not associated in any known way with previous recognized cases—often under circumstances which precluded the possibility of even indirect contact.”
W. L. Holt, 1916 - “I investigated [a polio epidemic] the best I could and was much surprised that I could trace hardly any cases to personal contact with others, there rarely being successive cases.”
C. K. Mills, 1916 - “During the present [polio] epidemic I have not been able to find any evidence of transmission of the disease to a healthy child or adult by a nurse, attendant or doctor in contact with cases of poliomyelitis.”
I. D. Rawlings, 1916 - “Any one who has had much experience with poliomyelitis is struck by the infrequency, relatively, of the secondary cases among direct contacts ... there were approximately 1,500 direct contacts, and yet but one possible case occurred among them. Also among the large number of people that came from New York and other infected areas not a single case occurred. One is constantly struck with the fact that there are relatively few contact cases.”
M. W. Richardson, 1916 - “Facts Against its [polio’s] Transfer by Direct or Indirect Human Contact.
[…]
2. Summer incidence of the disease: The vast majority of cases occur during the spring, summer, and fall, when personal contact is least intimate. With the onset of winter, when the population becomes more and more congested in houses, schools, etc., the disease becomes reduced almost to nothing. […]
3. Maximum prevalence of the disease in country districts where personal contact is least intimate at all times.
4. Failure to spread in general hospitals for children in which, up to recent times, cases have been received without let or hindrance.
5. Failure to spread in schools and institutions for children in which single cases have occurred and where personal contact with large numbers of children has been intimate.
6. Extreme rarity of the disease in doctors nurses, and other attendants upon persons sick with infantile paralysis.
7. Entire absence of infection in laboratory workers with the virus of infantile paralysis. Of course, in these two latter instances, the effect of age is important, but occasional infection would certainly be noted if the disease were markedly contagious.
8. Comparatively rare occurrence of more than one case of the disease in large families of children even under the markedly congested conditions of tenement life.
9. Epidemies cease oftentimes in mid-career, so to speak, when the human material has been by no means exhausted and the opportunities for direct or indirect contact are at their maximum.
10. Long continued immunity of cities and towns in close commercial relations with infected centres even though interchange of population with possibilities of indirect contact is marked. […]
11. The Colrain epidemic in 1908 was perhaps the most severe on record, thirteen per thousand of the population being affected, yet according to Emerson, who investigated the epidemic in this and neighboring towns, evidence of contagion was practically lacking.
[…] “The human contact theory cannot be made to fit these facts except by efforts so extraordinary that the value of the theory is thereby practically destroyed.”
T. H. Weisenburg, 1916 - ”I started out with the idea, after having read Wickman’s and Römer’s articles and from the New York reports, that the disease [polio] was personally contagious, but the more experience I had the more I got away from that impression.” […] “There is no instance of any nurse or physician who either acquired the disease or who carried the disease elsewhere. A number of the attending physicians with young children in their families went home daily and did not carry the infection with them. I have no doubt that many more such examples occurred in New York. It was the impression of all the nurses and physicians that poliomyelitis was not spread by personal contact.”
C. T. Brues, 1916 - “On account of several peculiar facts connected with previous epidemics of poliomyelitis, it has appeared possible that the disease may not be spread directly from one person to another” […] “The disease has always been regarded as more abundant under rural conditions.” […] “Cases of this disease do not usually appear in such a way that they can be positively traced to contact.” […] “Where large numbers of persons are crowded in congested dwellings, there is no tendency toward a rise in the incidence of poliomyelitis. This is abundantly shown by the details which have been cited in the preceding pages, and offers poor support to the view that these cases have been contracted as a result of contact with children suffering from the disease, or as a result of contact with healthy carriers of the poliomyelitis virus.”
C. F. Bolduan, 1916 - “Personally I believe we ought to abandon the idea that this disease [polio] is spread by direct contact of person to person by the respiratory passages (coughing, sneezing, spitting, etc.).”
H. L. Abramson, 1917 - “The fluids from forty patients with poliomyelitis were…injected intracerebrally into Rhesus 23 [monkey] … No effects were noted.”
W. H. Frost, 1917 - “Extensive epidemiologic observations are consistent in their testimony that definite lines of contact between [polio] cases can seldom be traced, and that the disease shows other features which we are not accustomed to expect in a directly transmitted infection.” […] “Almost without exception poliomyelitis reaches its highest prevalence, both endemic and epidemic, during the summer and autumn months, declining markedly with the advent of winter.” […] “Even in the most intense epidemics of poliomyelitis only a small proportion, usually not more than one to five per thousand, of the total population in the epidemic area is affected with recognizable symptoms of infection; yet the epidemics are invariably self-limited, declining rather sharply, often in mid-season, after only this small proportion of the population has been attacked.” […] “The most intensive study of numerous outbreaks has consistently failed to show precisely the sources and routes of infection.” […] “Direct contact between patients can not be traced in the majority of cases … a very considerable proportion of cases occur under conditions which absolutely preclude all probability of the patient’s having been in recent contact with any previously recognized frank case of poliomyelitis, or even any case of febrile illness.” […] “A large proportion, often a majority of cases, have certainly not been in contact with previous frank cases of poliomyelitis, either directly or indirectly, through distinctly traceable channels” […] “A large proportion even of children intimately exposed to acute cases escape the disease.” […] “It is noteworthy that epidemics have characteristically reached a higher degree of prevalence in the population of rural communities and small towns than in large, densely populated cities.”
H. Emerson, 1917 - “Contact between recognized [polio] cases can seldom be traced.”
W. A. Evans, 1917 - “Every effort to control infantile paralysis is based upon the theory that it is spread by contact and carriers; and yet it is with exceeding difficulty that we recognize the facts in relation to this theory. For instance, in New York City in this epidemic, in the report made about a month ago, it was stated that in 97% of the cases there was but one case to the family.” […] “The disease tends to end with the opening of schools, so that there is much reason for believing that it is not a disease that is due to contact infection.”
J. C. Geiger, 1917 - “Therefore taking everything into consideration relative to the sixty-six close contacts of Case No. I, particularly their supposed susceptible ages with the subsequent negative clinical results and especially since, for the majority, it undoubtedly constituted a first exposure to the disease, there seems to be sufficient reason to doubt the accepted present-day theory of the spread of acute anterior poliomyelitis by direct personal contact.”
M. J. Rosenau, 1918 - “Monkeys have so far never been known to contract the disease [polio] spontaneously, even though they are kept in intimate association with infected monkeys.”
M. W. Richardson, 1918 - “The fact that the hospital personnel in infantile paralysis does not acquire infection is an experience so nearly universal that the rare exceptions serve only to prove the rule.” […] “No case has come to my notice in all the literature in which a laboratory worker has acquired infantile paralysis in the course of his investigations, even though, as in one instance, the syringe broke and virus was sprayed into the face of the investigator.” […] “The epidemiological facts are strongly against the theory that infantile paralysis is spread from person to person by direct or indirect contact.”
C. H. Lavinder et al., 1918 - “In individual cases contact, either direct or indirect, with a previous case of poliomyelitis could but rarely be established, and in many instances the possibility of such contact could be satisfactorily excluded.”
R. B. Osgood et al., 1922 - “In poliomyelitis, the evidence of human contact contagion is so doubtful and rare that the burden of proof seems to be on those who maintain that the human carrier is the common source of infection.”
C. T. Brues, 1923 - “The seasonal prevalence of the disease [polio] lends no support to the theory of contact contagion.” […] “The geographical … relations of poliomyelitis present several features which … do not lend themselves to explanation on the basis of contact infection.” […] “Rural communities are almost invariably more severely affected than urban ones. This has been observed everywhere that the disease has become epidemic. Even in New York City during 1916, the incidence of poliomyelitis in the several boroughs of that city was almost exactly in inverse proportion to the density of population. It was highest in Queensboro and Richmond (Staten Island), less in Brooklyn and still far less on the thickly populated island of Manhattan, which includes one of the most densely crowded areas in the world.” […] “The epidemic severity, even in the parts of a large city, does not vary with the density of the human population … This is the lower East Side, the most crowded part of the city, where any disease spread by contact should become rampant, but its incidence rate was lower than that of any entire borough in the city … The conditions here, which I have been able only briefly to outline, directly contradict any theory of personal contact.” […] “It is impossible to establish the probability of direct contact with a previous case in more than a small proportion of cases.” […] “The failure of the disease to spread in hospitals to nurses, attendants or other patients has been noted incessantly by various observer.” […] “The several points which have been so briefly outlined show the many difficulties and contradictions which make it extremely difficult and to my mind impossible to understand the epidemiology of poliomyelitis on the assumption that it is a disease spread by personal contact.” […] “The failure of the personal contact theory to meet the requirements has led to the assumption that poliomyelitis is spread mainly by healthy carriers, or third persons harboring the virus, who may distribute it in a more infectious condition than those actually in the prodromal or acute phases of the disease. This accounts for the fact that contact with a severe case involves little chance of infection, and explains to some extent, although very imperfectly, the spatial spread of epidemics. Many features, however, as we have seen, show it to be inadequate” […] “No portal of entry has been found in laboratory experiments which could function under natural conditions without some medium for inoculation.” […] “Experimental poliomyelitis has so far been produced only by the injection of virus through what are, in most cases at least, wholly unnatural channels.” […] “Our present explanation of the spread of poliomyelitis through contact partakes of the same vague uncertainty that…fails to explain several important and well-authenticated epidemiological characteristics of the disease, and we must regard it at best as a weak working hypothesis.”
W. L. Aycock, 1926 - “However, epidemiologic evidence of direct contact is scant … the proportion of direct contact cases [polio] is reduced to an extremely small figure.”
A. C. Nickel, 1926 - “Last summer, Dr. E. C. Rosenow and I saw about fifty-five cases of poliomyelitis within a radius of 75 miles of Rochester, and frequently we would see a case in a very secluded spot where contact infection was quite unlikely.”
E. B. McKinley, 1929 - “Poliomyelitis is essentially a warm-weather disease, yet cases are exceedingly rare in tropical countries. It does occur in the Tropics, however, but never in epidemic proportions … Epidemiologists state that infantile paralysis is usually more prevalent in sparsely settled communities than in the large cities.”
The Journal of the American Medical Association, 1930 - “The etiology [of polio] has not yet been determined. With regard to the epidemiology, opinions vary. Direct contagion from the patients or from carriers has been accepted as the form of propagation of the disease, but the many cases in which the contagion is not in this form contraindicate this theory. Besides that, many research workers have reported cases of poliomyelitis in which patients did not transmit the contagion to their brothers, in spite of the intimacy and promiscuity in which they lived. Family epidemics are uncommon.”
W. L. Aycock, 1931 - “The epidemiologist encounters almost unparalleled difficulties in the study of the disease [polio]. It is only in the exceptional case that any relationship can be established with other cases. No practical tests have been available for the verification, for example, of suspected abortive cases or healthy carriers, and in the more general epidemiological features he is confronted with many seeming inconsistencies and paradoxes. Earlier students of the disease had little upon which to construct a conception of its epidemiology besides such observations as could be made in attempting to trace the infection from one case to the next occurring in the vicinity. One of the theories advanced was that the disease is transmitted by contact—a theory originating not so much in the observation of frequent contact itself but more in the suspicion that mild illnesses coincident with frank cases, not definitely diagnosable but suspected as abortive forms of the disease, aided in the dissemination of the infection. Failing even to find these in sufficient number to account for the spread of the disease, there was added the supposed transmission of the virus through healthy persons. The incompleteness of the early evidence for contact and perhaps the lack of laboratory procedures for its verification did not place the contact theory on such a firm footing that it could not readily be thrown aside for any newly proposed theory, of which there have been many.” […] “Some of the features of poliomyelitis which have seemed not to fulfill the criteria for contact transmission and which have been held as arguments against transmission in this manner are the infrequency of contact between cases, the infrequency of multiple cases in families or in institutions, the infrequency of transmission of the disease to nurses and attendants of cases and, in a more general way, the tendency to rural preponderance and the seasonal prevalence of the disease.”
K. F. Meyer, 1934 - “The extreme rarity of sister infections, even in the vicinity of definite cases in a family, is so striking that the epidemiologist reluctantly accepts the concept of contagion for the disease poliomyelitis.” […] “Well monkeys caged with poliomyelitic animals, or laboratory workers exposed to these apes, do not contract the disease.” […] “Lack of connection between cases of this disease is a constant epidemiologic feature; it is very difficult—usually impossible—to establish well-defined chain transmissions.” […] “Seasonal incidence, lack of tendency to spread in congested centers, schools, etc., and the behavior of poliomyelitis in the tropics and in rural areas, are phenomena which do not harmonize with the concept of contact transfer.”
L. L. Lumsden, 1935 - “Painstaking efforts were made throughout the studies to obtain all traces of transmission of the disease through personal contact, but it appears that in this outbreak in Louisville evidence of personal association between the cases of poliomyelitis, suggestive of cause and effect, was no more common than that which might have been found if histories had been taken of personal association between cases of broken bones occurring in the city in the same period.”
O. Dahl, 1935 - “Poliomyelitis, is not contagious. Contrary to the generally accepted belief, one cannot catch infantile paralysis, you have to build it. No one has ever proven it to be a fact that the condition known as poliomyelitis is an entity, a specific something, that can be transmitted to another. No one ever caught this condition simply by being in the vicinity of those who may be suffering with this condition.” […] “It would be just as reasonable for you to believe that drunkenness is contagious and that your children would become drunk by being in the vicinity of a group of people that were paralyzed drunk.” […] “We do have some ill informed M.D.’s who will tell you that Poliomyelitis is contagious for a period of about three weeks. It is hard to believe a reasoning mind can actually, and honestly believe such nonsense, for thousands of times children have slept together when one of them had infantile paralysis, and the others did not catch it. It is a rare incident that more than one or two children, in the same family, are stricken; although they are in daily contact.” […] “How is any thinking person to believe that there is a virus that in some way causes inflammation in the gray matter of the spinal cord of infants when this supposed to be virus has never been isolated? It is but a hypothetical something. A reasoning mind could better believe that the moon is made of cheese, for the moon at least has the shape and color of cheese. No one has ever seen, smelt nor felt, nor in any other way isolated this supposed to be poliomyelitis virus.”
B. Sachs, 1935 - “For many years I was in charge of a neurologic ward, and before there was much concern about poliomyelitis as an epidemic disease all the patients with neurologic conditions were kept in the general wards of the hospital. I cannot recall a single case of poliomyelitis that appeared to arise as a result of direct contagion from another patient in the ward. Those are very important facts. If the nasal orifice is the only portal of entrance it seems to me remarkable that there were not more cases in which the contagion was carried from one person to another, even allowing for the immunity of many persons.”
R. D. Defries, 1937 - “The fact that the disease [polio] occurs in epidemic form during the summer months … renders it difficult to explain fully the spread of the disease by contact.”
T. J. Meyers, 1937 - “There are some rather interesting characteristics of poliomyelitis epidemics. The disease is limited almost exclusively to certain seasons, late summer and early autumn … Contrary to what is commonly believed, poliomyelitis is rather infrequent in crowded districts and among children who frequent crowded places such as schools, churches, theaters, etc. The morbidity of rural districts exceeds that in larger towns, as much as a thousand fold.”
G. O. Barber, 1938 - “[Polio] is definitely not highly infectious. Until recently, cases were nursed from the start in general wards of general hospitals, and there have been no well-authenticated cases of infection to contacts. Certain of the cases in this recent outbreak occurred in crowded families, and were not reported until the illness had been in the paralytic stage for several days. During this time other children had been sleeping every night in the same bed as the paralyzed child, and in no case was one of these contacts affected later.”
H. A. Reimann, 1938 - “There is no obvious contagion in poliomyelitis of man.”
J. R. Paul, 1938 - “As to the possible means whereby the virus may spread through a community there is still no convincing evidence favoring any particular route … Nor has there been new or convincing work to explain satisfactorily the summer incidence of the disease [polio] or its higher prevalence in rural areas than in urban communities.”
C. C. Dauer, 1938 - “No direct or indirect association could be traced in the majority of [polio] cases even after the most careful and searching investigations.”
L. L. Lumsden, 1938 - “We do not know…with certainty, whether the disease [polio] is infectious; We do not know…whether it is directly or indirectly communicable from person to person.” […] “The general and usual epidemiological features of the disease all appear opposed to the hypothesis that poliomyelitis is a contagious disease spread among human beings by nose-to-nose or any other direct personal contact.” [...] “The efforts to reconcile the contagion hypothesis with the geographical distribution, seasonal incidence and other factual features of the disease appear to some of us more and more to compose a structure comparable to a pyramid of straw with the big end up. The contagion hypothesis may be right, but proof of it is yet lacking.” […] “What is the reason for such regional distribution of the disease we call poliomyelitis? We simply do not know. None of the usual hypotheses of spread—the contagion or other—appear to apply to it to a completely satisfactory degree.” [...] “It is quite usual in small [polio] outbreaks in rural counties for individual cases to develop in separate homes three or for miles apart without there being any evidence of direct or indirect personal contact having operated between persons afflicted.”
K. F. Meyer, 1939 - “Dr. Geiger: Before we begin to discuss the disease itself in humans, I feel we should have a clearer understanding of the laboratory side. Doctor Meyer, will you summarize the present status of poliomyelitis in the field of experimental research? Dr. Meyer: That is a difficult question to answer directly, since we are still baffled by the simple question, “What is the disease agent in infantile paralysis?” … We do not know whether it is a living germ or something else growing in the cells of the brain. We cannot isolate it like a germ in a test tube, and it is too small to be seen with a microscope. There is only one species of animal—the Old World monkey—in which we can induce the same disease as seen in children. Yet these monkeys are not as susceptible as man, since there is no record of one monkey catching the infection from another monkey by exposure.” […] “Dr. Geiger: Well, if we do not know a great deal about the disease itself, do we know anything about the mode of its spread? Dr. Meyer: In answering this question, let me say frankly that theories are numerous but facts are few. It is assumed that the disease agent is discharged from the mouth and nose, and enters the body through the same channels. Thus, direct exposure of the healthy with the diseased should convey the infection; but the lack of spread in families, schools and crowded places, throws doubt on this explanation. The fact that several cases may occur in the family indicates some hereditary disposition may play a role. But this does not explain why infantile paralysis appears toward the end of the summer in the temperate zone, and is rarely ever seen in the tropics.”
T. D. Deakin, 1940 - “One of the most striking features of poliomyelitis is the lack of obvious connection between cases … it is only in a small percentage of instances that a definite series of cases and contacts may be secured. The New York City Health Department investigated carefully the epidemic in Brooklyn in 1931. Of the first 500 cases, in 31 or only 6.2 per cent was evidence of contact with previous cases established. No proof of association with other cases could be obtained in any of the remaining 93.8 per cent. In an epidemic of 100 cases in Glasgow in 1928, in only two cases was it possible to trace any direct connection between the cases.” […] “[Ivar Wickman’s] reports of several small epidemics in Sweden in the early 1900’s still stand as the best evidence we have of the contagiousness of poliomyelitis.”
A. I. Kendall, 1940 - “At times numerous [polio] cases would appear suddenly in a limited area. Sometimes cases appeared simultaneously miles apart with no detectable contact one with the others. In epidemic areas it was exceptional rather than the rule to discover more than one patient in a single family where ordinarily intimate contact should produce multiple infections. This irregular discontinuity between individual cases of poliomyelitis, together with an unequivocal timespace relation in their incidence, was not wholly in accord with the usual pattern of a contagious disease.” […] “There is no evidence of spread of poliomyelitis among doctors, nurses or ward attendants in hospitals where large numbers of cases of flaccid paralysis may be interned.”
J. A. Toomey, 1941 - “No animal gets the disease [polio] from another, no matter how intimately exposed.”
A. I. Kendall, 1945 - “The epidemiological facts of poliomyelitis are these: … (2) A majority of cases of clinically diagnosable poliomyelitis (polioparalysis) occur sporadically, with no history of contact with previous cases. (3) Two cases of polioparalysis in one family are unusual, even though no precautions are taken to prevent cross infection. (4) Clinically diagnosable cases of poliomyelitis (polioparalysis) show little tendency to spread, even in schools or other places of public gathering. (5) Incidence of polioparalysis is no greater among doctors and nurses, in intimate contact with acute cases than it is among the civil population, even though the former are exposed freely to infection.” […] “Polioparalysis is not contagious.”
A. B. Sabin, 1947 - “It is remarkable that, unlike certain other infections of childhood, the epidemics of paralysis occur during the very months when the children are away from school.”
D. M. Horstmann, 1948 - “The fact that poliomyelitis is a summer disease has always been an obstacle in the acceptance of simple person-to-person contact as an explanation of its epidemic spread. The sudden burst of cases with the appearance of warm weather repeats itself again and again; and, if summer comes early, so do epidemics … Why, if contact alone is the answer, does not the virus spread in winter as do other contact diseases? … crowding and close quarters in winter seem more suitable for its spread than do summer conditions.” […] “In spite of all the information collected by many investigators in many lands we still cannot say … how it [polio] is spread”
E. B. Shaw & H. E. Thelander, 1949 - “The epidemiology of the disease [polio] remains obscure. There has been a tendency to depart from an early theory that the disease spreads by means of direct contact.”
A. B. Sabin, 1949 - “Among students of the epidemiology of poliomyelitis there are now three main views on the mode of spread of the disease, all regarding the human being as the primary reservoir of the virus. These views or hypotheses, for the sake of emphasis, may be called the respiratory, the alimentary, and the alimentary plus the nonbiting flies. The “respiratory” hypothesis postulates that transmission occurs when the virus is breathed out or otherwise expelled from the nose or mouth of one person and is then breathed in by another … According to the “alimentary” hypothesis the virus is transmitted by being put into the mouth as by contaminated fingers or food … Neither the “respiratory” nor the “alimentary” hypothesis attempts to account for the fact that 90 per cent or more of the cases and most of the epidemics occur during the late summer and autumn.”
W. J. McCormick, 1950 - “The disease [polio] rarely attacks more than one member of a family, and cases developed by contact are conspicuously rare.”
R. R. Scobey, 1950 - “The theory that poliomyelitis communicable has never been able to account for such anomalous and contradictory facts as the victimization of individuals who have had no contact with active cases; the non-communicability to doctors, nurses, and ward attendants; the absence of communicability to patients in hospitals and to individuals in communities when quarantines are not established; the rarity of multiple cases in the same family even where a child with poliomyelitis is known to have slept with another child; its greater incidence in small communities than in large cities where crowding exists and where, consequently, poliomyelitis should extort a staggering number of victims; and the increase in epidemics of this disease in spite of improved hygiene and education regarding precautionary prophylaxis.”
C. Armstrong, 1950 - “We are therefore confronted with the difficulty of explaining why poliomyelitis, a disease transmitted by close contact, should be most prevalent in that portion of the year when people spend most of their time in the open and why it should tend to wane rapidly when cool weather induces people to congregate indoors in search of warmth.”
Science News Letter, 1950 - “Strict and heavy quarantines for infantile paralysis does not stop polio epidemics, health and poliomyelitis authorities agree. All attempts to stop polio by quarantine have failed and authorities now consider it foolish to enforce it.”
A. Taylor-Smith, 1950 - “It is a most frequent thing to find that only one of a large family of children falls a victim [of polio], or that one only has been picked out of a large school class.”
A. B. Sabin, 1951 - “There is no evidence for the transmission of poliomyelitis by droplet nuclei.”
A. L. Hoyne, 1951 - “There is noting about poliomyelitis which seems more strange than its epidemiologic character … Considering that nearly all of the common acute infectious diseases predominate in the fall and winter or winter and spring, seasons when life is principally within doors and schools are in session, we are forced to ponder why poliomyelitis is epidemic in the summer.” […] “Can it be that the disease is transmitted only by person to person contact? It does not seem likely.” […]“It is a matter of extreme rarity for a patient to give a history of exposure to a known case of poliomyelitis.” […] “There is little to indicate that isolation has been a controlling influence in the spread of the disease during epidemics.” […] “Since the virus may be found in the intestinal tract for thirty-five days or possibly longer after onset of the disease it would seem logical to disinfect all body discharges before their disposal. However, in the Cook County Contagious Disease Hospital where the latter procedure has not been used there has never been a doctor, intern, nurse or any other member of the personnel who contracted poliomyelitis within a period of at least thirty-five years, nor has any patient ever developed poliomyelitis after admission to the hospital.”
A. B. Sabin, 1951 - “One of the important unsolved problems in poliomyelitis is why in temperate zones approximately 80 to 90 per cent of the cases occur during four months of the year in late summer and early autumn.”
R. R. Scobey, 1951 - “The first, and by all means the foremost fact that must be conclusively established is whether or not poliomyelitis is actually an infectious contagious disease, as has been commonly assumed and stated in the public health law. This assumption, it must be admitted, is almost entirely based on the results of animal experiments rather than on clinical investigations.” [...] ”Although poliomyelitis is legally a contagious disease, which implies that it is caused by a germ or virus, every attempt has failed conclusively to prove this mandatory requirement of the public health law. The manifest truth that we must take into consideration is that progress in poliomyelitis investigations has been impeded by this prematurely formulated public health law.”
J. A. Toomey, 1952 - “Polio has not been proved to be contagious.”
P. M. Holst, 1952 - “All our experience argues that the disease [polio] does not spread from contact with the clinically sick.”
R. R. Scobey, 1952 - “It is extremely difficult to understand how a human can contract poliomyelitis from another individual through dissemination of a virus by contact, carriers, excrement, unclean hands, unwashed fruits and vegetables, flies, etc. when a healthy animal in the same cage with an ’infected’ animal, exposed to all of these natural factors, remains unaffected.” [...] “The fact that an extensive epidemic of poliomyelitis was prevailing in the states of New York and Massachusetts in 1907, aroused the suspicion that the disease was infectious and communicable; it was therefore incorporated into the Public Health Law as such. However, conclusive evidence of contagiousness was not established during that epidemic nor in subsequent ones.” [...] “In addition to the failure to prove contagiousness of human poliomyelitis, it has likewise been impossible to prove contagiousness of poliomyelitis in experimental animals.”
B. Eskesen & B. Glahn, 1953 - [Epidemic of polio in Greenland] “It has not been possible to find definite means of contagion or disease spreaders.” […] “Means of contagion have not been proved.”
R. R. Scobey, 1954 - “It is now known that the most intimate contacts—such as healthy and sick individuals in one bed, the attendance of physicians and nurses upon the sick, the use of unclean linen, clothes, or beds, unsanitary conditions, insects and animals, post-mortem examinations of poliomyelitis victims, and other factors—have in no wise contributed to the spread of the disease.”
R. R. Scobey, 1954 - “Multiple cases in families present the nearest approach to the grouping of epidemiologically connected [polio] cases. There is no conclusive proof that the disease spreads under such circumstances like a contagious or infectious disease.” […] “The seasonal incidence of epidemics of poliomyelitis has always been one of the puzzling features of the disease. Epidemics are reported chiefly in the temperate zones.”
A. L. Hoyne, 1954 - “But we may ask is poliomyelitis actually contagious? … If poliomyelitis is a contagious disease as first maintained by Wickman about 1905 it is strange indeed that no one ever contracted it at County Contagious Hospital…where, it may be mentioned, the wearing of face masks is optional.” […] “Quarantine and isolation of patients have had no decernable effect in the control of epidemics.”
A. L. Hoyne, 1957 - “Is it not strange that we seldom hear of any hospital personnel who come in frequent contact with poliomyelitis patients during the acute stage contracting the disease? If poliomyelitis is contagious why has no one, during a period of 40 years, ever acquired the disease at Cook County Contagious Disease Hospital? In addition to the regular staff of graduate nurses, a new group of students is assigned for duty each month. Also clinics for medical students are held almost daily. Recently, a somewhat similar experience was reported in the Baltimore city hospitals. There it was believed that the personnel must have had “inapparent” poliomyelitis and possessed antibodies which afforded protection. It was decided to investigate the matter and Wehrle conducted a highly scientific study. He found that among 75 of the personnel, which included nurses, nearly one-third lacked sufficient antibody to provide protection. In some cases there was no antibody. If antibody is unnecessary for immunity what is the explanation for failure to acquire the infection when intimately exposed?”
N. Nathanson & J. R. Martin, 1979 - “Poliomyelitis has undoubtedly received as much attention from epidemiologists as any other viral disease of man. Yet in spite of intensive study over a century, many of the salient epidemiologic features of this infection must still be considered enigmas. Even some of the accepted dogmas about poliomyelitis can be debated as perhaps erroneous.” […] “No good explanation was ever documented for the occurrence of epidemics.” […] “One of the most characteristic features of poliomyelitis in the United States is its very marked seasonality … The regularity of this pattern over many years suggested that it was governed by a mechanism which should be ascertainable. Nevertheless, the underlying explanation has remained elusive.”
