Volume s1-15, Issue 2
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645


Summary and Conclusions

The present paper reports four year's work with drug control of malaria, in an unsanitated area in Panama. Various combinations of anti-malarial drugs were used including quinine sulphate alone or with plasmochin, and atabrine alone or with plasmochin. None of the methods used were particularly successful in reducing the malaria rate, except possibly the combination of atabrine and plasmochin. Monthly surveys over four years indicate the presence of cyclical variations in malaria parasite rate extending over several years. If treatment of any sort happens to be given during a down-swing in rate, success is nearly sure to follow; but if it is given on an upswing in rate, apparently nothing can stop the natural course of the cycle. Even atabrine, the most useful drug we have to date, was unable in 1933 to reduce materially the parasite rate during a period of eight months.

The effect of the addition of plasmochin to atabrine and to quinine in 1934 is obscured by the greater effect of the naturally decreasing malaria rate, as evidenced by comparative rates in our control town. It will be necessary to continue the administration of both drugs during the next up-swing of the parasite rate, in order to ascertain its effect.

Although we feel that the recent improvement in malaria parasite rate is not due solely to our efforts, we have no doubt but that the general health of our villagers is much improved over its condition in 1929, before our work started. At that time there was much more evidence, in the form of anemia, cachexia and other indications of malarial infection, of the ravages of the disease. By continued work we have reduced the numbers of chronic infections, and have taught the people to apply for drug treatment for their fevers, and have effected a consequent material improvement in general health conditions which may enable them to resist successfully the next onslaught of the disease.

Part II of the paper summarizes the malaria parasite rates found in twelve monthly surveys in 5 towns in the valley of the chagres River, and compares the percentages with those found in previous years. The evidence of our control town indicates that 1934 was a year of naturally declining parasite rates. The possibility that immunity is a family trait is discussed, and several illustrations are given in support of the theory.


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