An objection will be raised, and justly so, that we have up to this point been studying influenza in families irrespective of how many cases there are in each family. Until now the family with one case was classified exactly the same as the family with eight cases. In the following classification we have taken first all families with a maximum of one sleeping in one room, and sub-divided these into families with no influenza, those with one case, two cases, etc. We have likewise classified families with maxima from two to six per bedroom. For the sake of brevity we will consider only the last column of Table VII, influenza incidence among the individuals of the various classes of families for both epidemics. Study of the table will show a correspondence in the other columns. Solitary cases were more numerous in families with but one or two per bedroom (27 per cent.) and less frequent in families with three, four and five per bedroom, (23 per cent., 18 per cent., and 20 per cent., respectively). The families of six per bedroom form such a small group that here again they should not be considered. Multiple cases become progressively more numerous as the number of individuals per bedroom increases (14 per cent. in families of one per bedroom, 29 per cent. in two per bedroom, 41 per cent. in three, 51 to 52 per cent. in four, and 45 per cent. in five). Fifty-eight per cent. of families with a maximum of one per bedroom, 43 per cent. with two per bedroom, 35 per cent. with three, 31 per cent. with four and 35 per cent. with five had no influenza at all.
But here again, the fact that crowded families are usually large families interferes with drawing any conclusions. A family with four per bed room would generally be larger than one with two per bed room.
Frost observed that, considering the ratio of incidence in total white populations irrespective of housing as 100, and after adjusting all groups to a uniform sex and age distribution, the ratio where there were more than 1.5 rooms per person was 77, from 1 to 1.5 rooms per person the ratio was 94, and for individuals averaging less than one room per person it was 117. The attack rate showed a consistent increase as the number of rooms per person decreased.
Woolley observed, “Housing, if one includes in the term overcrowding, has surely been an important factor in spreading the epidemic. Whether it has had any appreciable effect upon the incidence of complications is a question. The epidemic has certainly gone faster and was over sooner because of the crowding; the hospital was filled sooner than it should have been as a result of the rapidity of spread of the disease, and overcrowding of the hospital occurred when with a less rapid spread it would not have occurred; but whether the number of fatalities or the number of pneumonias was greater than they should have been with less crowded conditions may be doubted.”
| TABLE VII. | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Relationship between crowding and number of cases in the family. | ||||||||||
| (Influenza appeared more frequently in crowded households and such families more frequently had multiple cases.) | ||||||||||
| Families with maximum per bed room of one. | ||||||||||
| (58.23 per cent. of these had no influenza.) | ||||||||||
| Cases developing in family. | Total such families. | Invaded in 1918–19. | Invaded in 1920. | Invaded in both epidemics. | Total families invaded. | Two or more cases. | ||||
| No. | Per cent. | No. | Per cent. | No. | Per cent. | No. | Per cent. | Per cent. | ||
| 1 | 85 | 55 | 17.68 | 37 | 11.89 | 7 | 2.25 | 311 | 27.33 | |
| 2 | 32 | 26 | 8.36 | 16 | 5.14 | 10 | 3.22 | 10.28 | } 14.44 | |
| 3 | 9 | 8 | 2.57 | 2 | 0.64 | 1 | 0.32 | 2.88 | ||
| 4 | 4 | 3 | 0.96 | 4 | 1.28 | 3 | 0.96 | 1.28 | ||
| 5 | 0 | 0 | ||||||||
| 6 | 0 | |||||||||
| 7 | 0 | |||||||||
| 8 | 0 | |||||||||
| 2 per bed room. | ||||||||||
| (43.35 per cent. of these had no influenza.) | ||||||||||
| 1 | 254 | 169 | 18.27 | 112 | 12.11 | 27 | 2.92 | 925 | 27.46 | |
| 2 | 135 | 112 | 12.11 | 64 | 6.92 | 41 | 4.43 | 14.59 | } 29.17 | |
| 3 | 79 | 65 | 7.03 | 38 | 4.11 | 24 | 2.59 | 8.54 | ||
| 4 | 40 | 35 | 3.78 | 16 | 1.73 | 11 | 1.18 | 4.32 | ||
| 5 | 11 | 9 | 0.97 | 8 | 0.81 | 6 | 0.64 | 1.18 | ||
| 6 | 3 | 3 | 0.32 | 0 | 0.0 | 0 | 0.0 | 0.32 | ||
| 7 | 2 | 2 | 0.22 | 1 | 0.11 | 1 | 0.11 | 0.22 | ||
| 8 | 0 | 0 | ||||||||
| 3 per bed room. | ||||||||||
| (35.34 per cent. of these had no influenza.) | ||||||||||
| 1 | 136 | 104 | 17.84 | 50 | 8.58 | 18 | 3.08 | 583 | 23.33 | |
| 2 | 103 | 77 | 13.21 | 55 | 9.43 | 29 | 4.97 | 17.67 | } 41.33 | |
| 3 | 59 | 51 | 8.75 | 29 | 4.97 | 21 | 3.60 | 10.12 | ||
| 4 | 43 | 40 | 6.86 | 16 | 2.76 | 13 | 2.23 | 7.37 | ||
| 5 | 22 | 22 | 3.77 | 9 | 1.54 | 9 | 1.54 | 3.77 | ||
| 6 | 12 | 12 | 2.06 | 5 | 0.86 | 5 | 0.86 | 2.06 | ||
| 7 | 2 | 2 | 0.34 | 0 | 0 | 0.34 | ||||
| 8 | 0 | |||||||||
| 4 per bed room. | ||||||||||
| (30.79 per cent. of these had no influenza.) | ||||||||||
| 1 | 31 | 24 | 13.64 | 10 | 5.68 | 3 | 1.70 | 176 | 17.61 | |
| 2 | 22 | 19 | 10.80 | 13 | 7.39 | 10 | 5.68 | 12.50 | } 51.60 | |
| 3 | 37 | 32 | 18.18 | 25 | 14.20 | 20 | 11.36 | 20.92 | ||
| 4 | 14 | 11 | 6.25 | 6 | 3.41 | 3 | 1.70 | 9.09 | ||
| 5 | 9 | 9 | 5.12 | 4 | 2.27 | 4 | 2.27 | 5.12 | ||
| 6 | 4 | 3 | 1.70 | 2 | 1.19 | 1 | 0.59 | 2.27 | ||
| 7 | 3 | 3 | 1.70 | 0 | 0 | 1.70 | ||||
| 8 | 0 | |||||||||
| 5 per bed room. | ||||||||||
| (35 per cent. had none.) | ||||||||||
| 1 | 8 | 6 | 15.00 | 4 | 10.00 | 2 | 5.00 | 40 | 20.00 | |
| 2 | 6 | 5 | 12.50 | 4 | 10.00 | 3 | 7.25 | 15.00 | } 45.00 | |
| 3 | 3 | 2 | 5.00 | 2 | 5.00 | 1 | 2.50 | 7.50 | ||
| 4 | 2 | 1 | 2.50 | 2 | 5.00 | 1 | 2.50 | 5.00 | ||
| 5 | 4 | 2 | 5.00 | 3 | 7.50 | 1 | 2.50 | 10.00 | ||
| 6 | 2 | 2 | 5.00 | 2 | 5.00 | 2 | 5.00 | 5.00 | ||
| 7 | 0 | |||||||||
| 8 | 1 | 0 | 0.0 | 1 | 2.50 | 0 | 0.0 | 2.50 | ||
| 6 per bed room. | ||||||||||
| (50 per cent. had none.) | ||||||||||
| 1 | 2 | 1 | 10.00 | 1 | 10.00 | 0 | 0.0 | 10 | 20.00 | |
| 2 | 1 | 1 | 10.00 | 1 | 10.00 | 1 | 10.00 | 10.00 | } 30.00 | |
| 3 | 2 | 1 | 10.00 | 1 | 10.00 | 0 | 0.0 | 20.00 | ||
| 4 | 0 | |||||||||
| 5 | 0 | |||||||||
| 6 | 0 | |||||||||
| 7 | 0 | |||||||||
| 8 | 0 | |||||||||
The housing methods in the cantonments and even in the tent camps resulted in a degree of congestion and close physical contact among individuals that was attained in no civil communities with the possible exception of some institutions. In cantonments the number of men in individual rooms ranged from 30 to 100 and even under the best circumstances there was very evident close crowding. An individual in any of these large rooms contracting a contagious disease had opportunities to spread it by contact and by droplet infection not only to one or two others, as in the case of the average family, but to a large group of the men in the same room. A vicious circle was thus formed which tended to propagate the disease throughout any camp with utmost rapidity. Brewer has compared the influenza incidence rate in the principal white organizations at Camp Humphreys with the floor space allowed each man in the respective organizations, and concludes that, “It is not proper or just to attribute the differences shown, alone to the amount of floor space allowed each organization, but it certainly points very strongly to the fact that the incidence of the disease varied with the density of the population, although not with mathematical regularity.” Brewer cites regiments which although housed alike showed definite variation in the influenza incidence. This merely shows that other factors also play a part. Thus, in one instance, the difference in the two regiments was in length of service. Brewer also found that among the white troops the incidence of pneumonia appears to vary with the density of the population.
V. C. Vaughan has reported on the relationship between incidence in tents and in barracks at Camp Custer. From this one observation it would appear that the incidence is little changed under the two conditions.
“During September and October, 1918, a study was made on the relationship, if any, of influenza to methods of living. Of the command, 3,633 were in tents. The morbidity per thousand in these was 129. There were in barracks 36,055. The morbidity per thousand among those was 275. At first glance the lower morbidity of those in tents is striking, but going further into the matter it was found that the entire morbidity of the Quartermaster Corps was very low. Of the Depot Brigade 2,881 were in tents, with a morbidity of 128 per thousand, while 3,824 were in barracks, with a morbidity of 134 per thousand.”
Howard and Love offer three reasons why during the last four months of 1918 the deaths from influenza and pneumonia in the Army in the United States ran at a rate nearly three times as high as that among our troops in France: First, that the troops in the United States were recent recruits and therefore more susceptible to disease; second, that probably many of the troops in France who had seen much longer service had had the disease in mild form in the early spring; and, third, that the method of housing was entirely different in France. There the men were spread over a wide territory and whenever in rest area they were billeted in houses rather than crowded into barracks. Furthermore, they were living much more in the open. It was found that in commands of the Service of Supply, where troops were housed in barracks with a large number of men to a single room, the epidemic ran much the same course with high mortality, as it did in the cantonments in the United States. The percentage of infection and the fatalities from influenza and pneumonia in France were much greater among troops of the S. O. S. than among troops at the front.
Domestic cleanliness.—We have studied the relationship between influenza incidence and the cleanliness of the household by the same method used in studying overcrowding. In Table VIII we have classified according to cleanliness and according to the number of cases developing in each family. We have had four subdivisions, “very clean,” “clean,” “dirty,” and “very dirty.” There is greater opportunity for erroneous results in this table than in the one preceding because the standards of cleanliness are difficult to define. As a matter of fact we are guided entirely by the inspector’s own impression of each household, as she examined it during her visits. The following is an excerpt from the instructions given each inspector on this subject: