All the races are susceptible to malaria , yet numerous writers (Lind, Boudin, William, and others) maintain that negroes enjoy a relative immunity.
The English Niger Expedition (1841-1842) consisted of three ships; the crews were made up of 145 whites and 158 negroes. Among the whites, 130 were attacked with fever, of whom 40 died; among the negroes, only 11 suffered, and these from mild cases, none of them dying. It is interesting to note that the 11 affected negroes came from the West Indies and had lived some time in England, while the remaining negroes were Africans, principally Kru people. This would seem to indicate that the relative immunity was not in the race, but was acquired by the negroes in the malarial regions. Moreover, this assumption is supported by the fact that the negro children in Senegal suffer in an extraordinary way from malaria (Borius).
The garrison of Ceylon showed the following distribution of malaria among the different races. Among 1000 men of the force there occurred:
Moreover, there are regions, like Madagascar and French Guiana, occupied only by negroes, other races not being able to stand the malaria (Maurel).
In East Africa, according to Plehn and R. Koch, the negroes of the coast suffer from only mild attacks or are immune. Koch believes that the coast negroes are immune by heredity. Laveran assumes, with Darwin, that the negroes as a race have a natural immunity, and cites as proof the fact that when the disease broke out on the island of Mauritius, which was free from malaria before 1866, the negroes were spared almost to a man.
Against their assumption we offer the previously mentioned morbidity among negro children, and also the fact, observed by Plehn and Koch, that in East Africa only the coast negroes are immune, while the Mschamba negroes of the non infected Usambara Mountains, the negroes of Dahomey,- the Km and Akra negroes, the Sudanese, in one word, the negroes of the non infected interior, are susceptible.
Other communications question even the relative immimity of the negroes. In the United States the mortality of the negroes from malaria , in contrast to that of the whites, stands in a relation of 48.3 to 30.7 (quoted from Davidson). Pieroz found that in the West Indies the negroes suffered the same as other races from malaria.
The general impression seems to be that the Ethiopian race has the faculty, in malarial places, of acquiring a considerable immunity.
Other races seem to possess this faculty to a lesser degree, or, like the Caucasian, not at all. It has been generally observed, for instance, that Creoles manifest no immunity, but, on the contrary, suffer extremely frequently and severely.
The American race (Indians) are, according to Maurel, very susceptible, though he became acquainted with one tribe (Galibi Indians) in which he never saw malaria . The Caucasian race is susceptible in all its branches; and of this race, the Europeans are least resistant.
The Arabians are about equally susceptible, though they show pernicious cases less frequently.
According to Fayrer, the native Indians are more frequently attacked than the Europeans; in ordinary years the mortality of the Europeans from malaria amounts to 7 per cent., that of the natives, to 18 per cent. Again we must repeat our caution as to the validity of such figures as these. In India it has been the practice to consider every case of "fever" as one of malaria.
In Tongking malaria is wide spread. Moraud observed that the Tongkingese are as susceptible as the Europeans; the Chinese are also very susceptible.
The Japanese seem equally predisposed. In the year 1884 the Japan army showed 36.3 per cent, of its whole force affected with malaria (de Santi).
According to Pellereau, on the island of Mauritius (Ile de-France) the frequency of the disease descends as follows: Indians, Creoles, Europeans, Chinese. The Chinese present usually milder symptoms.
F. Plehn reports that the Chinese coolies on the Kongo and on Fernando Po Island are frequently attacked.