4 N. H. AGRI. EXPERIMENT STATION [Bulletin 243 



laria by anopheline mosquitoes. In 1900 the American Yellow Fever 

 Commission (Drs. Reed, Carroll, Lazear and Agramonte) demonstrated 

 the transmission of yellow fever by the yellow-fever mosquito. 



Four diseases are known to be transmitted from one human' to another 

 by mosquitoes, and these diseases can be contracted in no other way. 

 The mosquito must first bite a person having the disease, and then later, 

 upon biting a healthy person, may give the latter the disease. Malaria 

 fever (ague, chills and fever) is transmitted by many species of the 

 genus Anopheles. Included under this are three kinds of malaria fever 

 which will not be differentiated in this paper. Yellow fever is trans- 

 mitted by the yellow-fever mosquito {Aedes oegypti L.). Dengue fever 

 (breakbone fever) is transmitted by Culex quinquejasciatus Say and 

 Aedes cegypti. Filariasis (elephantiasis) is transmitted by Culex quin- 

 quefasciatvs. 



These are tropical or sub-tropical diseases, the last three of which are 

 never found in New Hampshire, because the mosquitoes carrying them 

 do not occur in the state. Malaria is an extremely rare disease in New 

 Hampshire. Dr. Charles Duncan of the State Board of Health writes: 

 "As far as my knowledge goes, for the last twenty-five years no diagno- 

 sis of malaria has been made or confirmed by the Department labora- 

 tory. Physicians will occasionally send a blood sample with diagnosis 

 of chronic malaria, but the laboratory has never been able to prove it." 

 The organisms causing malaria are often very difficult to find in the 

 blood of persons having chronic malaria, and almost impossible if the 

 patient has been treated with quinine. Nevertheless, persons who have 

 contracted the disease elsewhere must occasionally enter the state, and 

 as Anopheles mosquitoes are well distributed there is the possibility that 

 local outbreaks of malaria may occur. 



NEW HAMPSHIRE CONDITIONS 



Although we have thirty-eight or more different species of mosquitoes 

 in the state, yet about one-fourth of these never bite humans, and of 

 the remainder, only eight or ten may be considered general pests. The 

 common mosquito pests, in any particular locality during a summer, 

 will generally consist of not more than five or six different species. 

 These important species will vary from year to year, depending on 

 local breeding conditions, climate, and other factors. Many of our mos- 

 quitoes occur in abundance only rarely or in restricted localities. The 

 greater part of the field studies that are the basis of this report have 

 been made in Rye and the neighboring coast towns, where mosquitoes 

 are more abundant than elsewhere in New Hampshire. Only inciden- 

 tal observations have been made in other parts of the state. 



In Rye, in the summer of 1928, five species occured in great enough 

 numbers to be considered pests. From the middle of May Aedes com- 

 munis and Aedes excrucians were not uncommon in the wooded areas. 

 They bred in the early spring pools in woodland and swamp and were 

 present for about two months. They generally remained in the woods 



