In 1836, according to Gluge, 40,000 persons suffered from the disease in Berlin alone.
In London, in the 1847 epidemic, it has been calculated that at least 250,000 individuals took sick, and in Paris, according to Marc d’Espine, between one-fourth and one-half of the population developed the disease, and in Geneva not less than one-third.
Leichtenstern informs us that in 1890 the early reports were made by clinical men and were mere presumptions. They were almost universally higher than the later statistical findings. The early estimates for the morbidity in several German cities were from 40–50 per cent. On the other hand, one of the highest statistical reports recorded by Leichtenstern was for Strasbourg in which 36.5 per cent. of the individuals became sick. The average morbidity reported by him ran between 20 and 30 per cent. The difference is accounted for in part by the fact that some of the very mild cases were not recorded in the statistics, and in part by the tendency in giving estimates, to exaggerate.
Auerbach has collected the statistics of 200 families distributed throughout the city of Cologne. He found that 149 of these families (75 per cent.) were attacked. In these, 235 were ill—59 men, 95 women, and 81 children. The larger number of women was explained as due to the illness of the female servants. He estimates each family as consisting on an average of six individuals, and concludes that 20 per cent. were taken with the disease.
Following the 1889 epidemic, Abbott concluded, on a basis of questionaires sent out to various individuals and institutions in the State of Massachusetts, that 39 per cent. of the entire population had been attacked, in all about 850,000 persons.
Moody and Capps, in December, 1915, and January, 1916, made a survey of the personnel and inmates of four institutions in Chicago, the Michael Reese Hospital, the Illinois Training School for Nurses, the Old Men’s Home, and St. Luke’s Hospital Nurses Training School, making a total of 677 persons surveyed, of whom 144 developed influenza, making a percentage morbidity of 21. They remarked that there were many others with colds who remained on duty and were not included in the table and were not diagnosed as influenza.
We have already described the relatively low morbidity and mortality in the early spring epidemic in the United States. According to Soper, the total number affected in March, 1918, at Camp Forrest and the Reserve Officers Training Camp in the Oglethorpe Camps was estimated at 2,900. The total strength at that time was 28,586. The percentage morbidity then was probably a little over 10 per cent. Dunlop, in describing the May, 1918, epidemic in Glasgow, says that it was more limited in extent, as well as milder, than the later epidemic.
It has been estimated that in the autumn epidemic in the United States Army Camps one out of every four men had influenza, and one out of every twenty-four men encamped in this country had pneumonia. During the four autumn months of 1918, 338,343 cases of influenza were reported to the Surgeon General’s Office; there were 61,691 cases of pneumonia.
Woolley reports that among the soldiers at Camp Devens, Mass. 30 per cent. of the population was affected.
At Camp Humphreys, 16 per cent. of the entire personnel developed the disease. The camp had an average strength of 26,600 individuals. Fifty-two per cent. of the entire number of cases occurred during the peak week, which ended October 4th. The outbreak began September 13th and ended October 18th.