12 U. S. BUREAU OF FISHERIES. 



PARTICIPATION IN ANTIMALARIAL CAMPAIGN. 



Responding to a request from the Surgeon General of the United 

 States Public Health Service, Scientific Assistant S. F. Hildebrand 

 was detailed in February to cooperate with that Service in making 

 inspections in the Southern States and in conferring and advising 

 with the various public health officers, Federal, State, and munici- 

 pal, in the use of minnows for the destruction of the immature mos- 

 quito. As the work was extended to various points in 12 States, it 

 was found that public health officers generally, when properly ac- 

 quainted with the conditions of success of mosquito control by the 

 use of fish, were glad to make use of a method which in many cases 

 was both practicable and inexpensive. Many favorable reports, 

 showing considerable savings accomplished by the use of fish under 

 favorable conditions, have been given by sanitary engineers and 

 others. As compared with control by oiling, the elimination of mos- 

 quitoes by the use of minnows is not only inexpensive but also rela- 

 tively enduring in effect, if the bodies of water are permanent. 



There appears at this time to be no other mode of mosquito control 

 inexpensive enough to be widely applicable in rural communities 

 where measures of drainage and oiling could be employed only at a 

 per capita cost that renders them impracticable. The principal fish 

 used is the common southern top minnow {Gamhusia afjinis)^ al- 

 though the star-headed minnows {Fundulus notatus and Fundulus 

 nottii) are being used to a limited extent. Many observations in 

 various localities give positive demonstration of the effectiveness of 

 Gambusia in eradication of mosquito breeding under appropriate 

 conditions. 



It is not to be inferred that mosquito control by fish is attained 

 automatically ; rather is the exercise of intelligence, knowledge, and 

 care essential for success. It must be borne in mind, too, that as yet 

 there have been discovered only some of the conditions of successful 

 control. Much remains to be learned by repeated observations and 

 experiments before the broadest use of fish as an agency for the 

 prevention of malaria will be possible. Therefore advice and demon- 

 stration of what is now known must not be allowed to displace the 

 plans for further investigational work. The same assistant will 

 continue to prosecute investigations and extend j^ractical services 

 with particular reference to the conditions in Southern States. 



FISH AND MOSQUITO STUDIES AT MOUND, LA. 



Previous reports have mentioned the cooperative investigations 

 which were being pursued with the Bureau of Entomology at the 

 field laboratory of that Bureau at Mound, Ln., E. L. Barney being 

 the Bureau's resident agent in charge. The observational and ex- 

 ])erimental work at that station was brought to a close about the 

 middle of the fiscal year in order that the accumulated data might 

 be compiled and a report prepared. Reports on certain phases of 

 this investigation have been prepared, but the completion of a final 

 report has been delayed by the loss of an assistant and by the un- 

 avoidable exactions of other duties. 



