1. 1. The results of various studies by other workers on the spleen and parasite rates in Indians, Malays and Bantu are summarized. 2. 2. The results of our own observations on Khonds in India, and on Masai and Bantu in East Africa are also summarized and compared with the foregoing and with one another. 3. 3. It is pointed out that wide differences may be found in the malarial status of communities in the same country and, in the case of the Bantu, of the same race; while close similarities occur in different countries. 4. 4. The results of experimental infections in birds and monkeys are cited and interpreted in terms of the two states of allergy and immunity. The probable significance of these is illustrated by reference to the role of the two states in tuberculosis. 5. 5. It is suggested that the observed contrasts in the spleen and parasite rates in diverse communities may also be explained in terms of immunity and hypersensitivity. 6. 6. It is concluded that the immune status is dependent not on race but on the frequency of infection; and that the most accurate index of endemicity is the frequency of infections in the non-immune, that is the rate in early infancy. 7. 7. While a consideration of the Spleen Rate and Endemic Index may be of value in forming an estimate of endemicity and immunity when similar communities are being compared, these indices may be misleading when the epidemiological surroundings are dissimilar. 8. 8. A consideration of the variation with age in the spleen and parasite rates throws more light on endemicity and immunity and on such variation a rough classification may be made into immune and sub-immune communities. 9. 9. But it is suggested that by far the most sensitive index at present available for field studies is the average parasite count, and its variation with age. c 1937.
Lower Perak, an alluvial plain, much of it below spring tide levels, lies between tidal reaches of the large Perak and Bernam rivers. It has a mixed rural population, about 40 per cent. being Malaysians. Inspection, with individual card records, was made of 2, 388 boys in vernacular schools aged 6 to 16 years, local prejudice exempting girls. The diet, largely rice, of these children appears deficient in animal protein, and probably in calcium, iron, phosphorus, and vitamin B. They show few signs of deficiency diseases, have a dental caries rate of about 70 per cent., and one-third had poor muscular development. They suffer mainly from fever, anaemia and skin infections. * An asterisk denotes that the paper dealt with is thought to be of more than ordinary interest to tropical readers. As ages were quite unreliable, only the 513 presenting birth certificates were grouped to the nearest birthday. [img 1T161260A.tif] Comparisons are made with the Baldwin-Wood scale for American medium type boys, who at every age are of superior weight. Full correlation tables are given for the 513 and 2, 388 boys. To eliminate doubtful ages the, Baldwin-Wood tables were used to calculate the mean weights of Americans at the height of the Perak boys, and now the Americans only [img 1T161260B.tif] come out slightly higher than these. The essential difference therefore seems to be more a matter of size and physical development in relation to age, than any significant change in-ratios at different ages. Comparison was made with Kedah measurements. This is a similar district 120 miles north of Lower Perak. Curves are used which are not strictly comparable, as some girls were included, but Dr. J. H. STRACHAN took out the figures of 1, 018 Kedah boys. These are compared with the 2, 388 Perak boys, in weight for inches in height. Although the conditions and districts seem in all respects similar the Kedah boys are significantly lighter for all heights. No explanation has been found for this. The authors insist on the usefulness of correlation tables. " It is obvious that the medium American boys are much heavier than the Malaysian children. But the second American weight/height curve seems to show that if one selects for comparison boys of the same stature at each age, the American boys would be on the whole only slightly heavier than the Lower Perak boys." This investigation has got the utmost value from rather unpromising materials. Any school worker will gain some new viewpoints from its careful perusal. James Kerr.
A letter from Drs. G. I. Robertson, D. G. Davey, and Sir Hamilton Fairley (December 6, 1952, p. 1255) reported that a proguanil-resistant strain of Plasmodium falciparum from Malaya had proved to be resistant also to pyrimethamine (" daraprim "). Proguanil-resistance in Malayan strains of P. falciparum has been recognized since 19491; and if a true cross-resistance exists, this might-as implied by Dr. J. S. K. Boyd (February 7, p. 337)-go far to explain the pyrimethamine failures described in our paper (January 31, p. 253). Proguanil has been so widely used throughout Malaya for the past six years that there can be few strains of parasite which have not yet come into contact with it; thus there is little chance of deciding now how the "parent" strains (without previous contact with proguanil) might have responded to pyrimethamine. We have not, however, been able to confirm that there is any consistent cross-resistance between these two drugs in naturally acquired falciparum malaria since pyrimethamine was first used in Malaya in 1951. Pyrimethamine failures have been successfully treated with normal doses of proguanil, and proguanilresistant infections have responded readily to pyrimethamine. In some of these cases an interval of several days was allowed to elapse between treatments, so the possibility of a combined action of the two drugs should have 'been small. We consider that these apparently conflicting results can best be explained by assuming that some present-day strains of P. falciparum in Malaya possess a " natural" resistance to pyrimethamine, whether or not any particular strain is also demonstrably resistant to proguanil. With this species of parasite, a true cross-resistance has still to be proved. REFERENCE 1 British Medical Journal, 1950. 1, 147.
This paper from the Malaria Research Division, Institute for Medical Research, Federation of Malaya, summarizes the results of studies on the suppression of malaria by synthetic drugs. Such studies began 25 years ago, and, in spite of interruptions in the work due to the Japanese invasion and due to banditry, studies are reported here on the effects of giving mepacrine in doses of 0.3 gm. once a week; proguanil in doses of 0.1 gm., 0.2 gm., 0.25 gm. and 0.3 gm. once a week; chloroquine in doses of 0.25 gm. once a week; and amodiaquin [camoquin] in dosos of 0.4 grn. base once a month. The populations upon whom the studies were made were labourers and their families-Tamils, Malays, and Javanese, on 3 estates in Selangor, and Negri Sembilan, Federation of Malaya, between December, 1946, and February, 1949. Each population was divided into 3 comparable sections, 2 of which received test drugs, while the third received a placebo and so formed a control group. Drugs were issued under the supervision of a Malaria Research Officer. Those people who developed fever wore supervised and treated by a hospital assistant resident on each estate. Thick blood films from such patients were studied. Parasite and spleen surveys were done every 3 months. Malaria transmission was assessed by the incidence of malaria in unprotected infants, who were not given suppressive drugs until after their first attack; and by the results of mosquito dissections. The commonest vectors woreA. letifer, A. maoulatus and A. umbrosus. The results of the tests of suppressivo drugs are shown in a series of tables, charts, and diagrams. Malarial transmission was considered light during the period of these trials. Chloroquino 0.25 gm. base once weekly proved the most effective drug in suppressing malarial attacks. There was little difference between proguanil in various doses, or between proguanil and mepacrine, but these two drugs were much cheaper than chloroquine or amodiaquin. All the drugs reduced the parasite and spleen rates. No significant toxic symptoms were observed with any of the drugs used. S. Bell.