Malaria 623 



and effective enough against exo-erythrocytic stages to insure complete 

 prophylaxis and true cure. The search for such a drug is still in progress.^ 

 At present, the closest approach to the desired effects has been obtained 

 with combinations of drugs. For example, the combination of quinine 

 and pentaquine produces a low relapse rate in tertian malaria (73, 112). 

 Likewise, quinine and plasmochin, as well as quinine and paludrine, 

 have real value in clearing up relapsing cases (73). Such combinations 

 as paludrine and atebrin, paludrine and chloroquine, and atebrin and 

 chloroquine also have been used in malignant tertian. 



Control 



Mass treatment and prophylaxis, with an ideal drug administered 

 to a docile or thoroughly cooperative population, probably could elimi- 

 nate malaria from a given area without distvirbing the local mosquitoes. 

 Since the perfect drug is not yet available and the human factor is rather 

 unpredictable, the most effective method for completely controlling ma- 

 laria involves the reduction of anophelines to such a low density that the 

 disease cannot be maintained in a given area. Successful results within 

 the shortest possible time would require a combination of mosquito 

 control and suppressive chemotherapy. 



Long range measures, such as drainage of marshy areas and the stock- 

 ing of natural and artificial lakes with fish which eat mosquito larvae, 

 are effective deterrents to the breeding of mosquitoes. Treatment of stag- 

 nant pools and marshes with larvicides can be very effective where local 

 conditions permit such measures. Adequate screening of houses tends to 

 prevent contact of mosquitoes with man. In addition, some of the newer 

 insecticides promise striking results in the direct attack on adult mos- 

 quitoes. For instance, residual DDT spray has been tested in several dis- 

 tricts of Bombay Province with a population of about 1,600,000. After 

 one year of spraying human and animal shelters at intervals of 6-8 weeks, 

 the apparent incidence of malaria was reduced by 40-70 per cent in dif- 

 ferent areas (117). Practical tests in several tropical towns have shown 

 that malaria can be controlled to a satisfactory degree by combining the 

 use of DDT with suppressive chloroquine therapy (41). With the sys- 

 tematic application of available methods based upon sound knowledge 

 of anopheline ecology, the practical elimination of human malaria now 

 seems to be a distinct possibility. Attainment of this goal is retarded 

 mainly by economic factors. 



LITERATURE CITED 



1. Andrews, J. M. and W. E. Gilbertson 1948. /. Nat. Malar. Soc. 7: 167. 



2. Barber, W. A. and H. W. Komp 1929. Publ. Health Rep. 44: 2330. 



3. Beach, T. de V. 1936. Atner. J. Trop. Med. 16: 147. 



"A fairly recent survey of antimalarials has been edited by Wiselagle (120); a later 

 one has been ptiblished by Coatney (28). 



