ECONOMIC IMPORTANCE OF MOSQUITOES 325 



THE GENERAL ECONOMIC IMPORTANCE OF MOSQUITOES 1 



By Professor JOHN B. SMITH 



RUTGERS COLLEGE, NEW BRUNSWICK 



~VTO one should be better qualified than a Jerseyman to speak on 

 -^ this subject, for no state in the union has suffered more in repu- 

 tation and in arrested prosperity from mosquitoes than New Jersey. 



During the four or five years last past, I have had opportunity to 

 observe conditions closely, and there is not a section whose develop- 

 ment has not been in some way affected by this insect pest. 



First: by the carriage of malarial disease, and by the term car- 

 riage, I mean, of course, not the direct transmission from one indi- 

 vidual to another, but that service as intermediate host in the develop- 

 ment of the parasitic organisms that cause the disease. 



Anopheles occurs throughout our state, although the A. maculi- 

 pennis, which is the only one of our species known to be affected by 

 the parasite, is comparatively rare and is, curiously enough, more 

 abundant in the more northern, hilly portions than in the southern 

 lowlands, where breeding places are more numerous. 



Malarial diseases are much less common with us than they were a 

 few years past, and that is due partially to the improvement of sani- 

 tary conditions which lessens mosquito breeding in densely populated 

 districts, and partly to the much more thorough treatment which a 

 patient now receives from the attending physician. 



It requires the presence of a patient infested with the plasmodium, 

 as well as of the proper species of Anopheles, to start an epidemic of 

 malaria, but the mosquitoes need not be at all common to make 

 trouble. I have in mind an instance very much in point: A village 

 of high-class residences, well-located, generally healthy and where mos- 

 quitoes were accounted among the rarities; but, as it happened, the 

 few that did occur were A. maculipennis. Into that community, where 

 no case of malaria had ever been known, was introduced a gang of 

 Italian laborers, recent immigrants, it was later found, and most of 

 whom had been affected with the fever in Italy. 



Before the end of the season a considerable number of cases of 

 the sestivo-autumnal variety had developed in the village and some of 

 them of the most severe type. This led to a search for the cause, 

 and the breeding places for the few mosquitoes that occurred were 

 located and abolished. Italian laborers have been tabooed in that 



