The diseases in the table of deaths do not account for all the deaths, the others having been from other diseases, accidents, etc.
In studying the Manila statistical reports more in detail we note that during 1920 there were reported 64 cases of diphtheria, 387 of measles and 577 of typhoid fever. The reasons for the high death rate in 1918 are clearly seen, namely, the epidemics of influenza and smallpox. As is the case in nearly every epidemic of influenza, the increase in deaths from this disease was accompanied with a large increase in deaths from acute bronchitis and the various pneumonias, conditions that in many cases should have been ascribed to influenza. The smallpox epidemic during 1918 was brought under control by a very extensive vaccination campaign. Only one death from this disease occurred in 1920.
During 1920, there were reported in Panama 95 cases of diphtheria, 313 of influenza, 154 of measles, 9 of typhoid fever, 4 of scarlet fever, 14 of smallpox and 311 of tuberculosis.
During the same period there were reported in St. Thomas 6 cases of chickenpox and 40 cases of tuberculosis. No cases of influenza, smallpox, measles or typhoid fever occurred. From reports for the year of 1921, it is noted that an extensive although not severe epidemic of measles has been present in the Virgin Islands during said year.
From the above tables we note that as far as actual causes of deaths are concerned the cosmopolitan diseases play a more important rôle than those we designate tropical diseases. Tuberculosis ranks first, other respiratory infections come a close second. Organic diseases of the heart and other degenerative diseases, such as chronic nephritis, are also noted for their frequency. The gastro-intestinal infections, typhoid fever, dysentery, diarrhoea, probably serve as a barometer of the sanitary conditions of a city.
But there are many other diseases whose importance from an economic standpoint may not be fully appreciated from mortality tables. Notable among these are venereal diseases, malaria, filariasis, yaws and hookworm diseases. Further it may be noted that many diseases without being the direct cause of death have a distinct bearing on the mortality. Amongst these we note particularly the various worm-infestations. The experience in Bilibid prison is an illustrating example. The mortality amongst the prisoners dropped markedly after the inmates had been cured of their various worm conditions.
Rheumatic Fever and Scarlet Fever.—From a study of the statistical reports and from the writings of various authorities there would seem to be two cosmopolitan diseases, which are of extreme rarity in the tropics, rheumatic fever and scarlet fever.
It is true that in the Gold Coast report for 1911 there are noted 614 cases of rheumatic fever with one death.
There does not, however, appear to be any striking increase in admissions for valvular disease of the heart as would naturally be expected.
In Calcutta, in 1911, there were 74 deaths from rheumatic fever.