February, '13] HUNTER: MEDICAL ENTOMOLOGY 33 



tions have been used as a basis in certain calculations we have made 

 but in the case of malaria we find reliable figures already available. 



Dr. L. O. Howard has made a very careful and conservative estimate 

 of the loss to the United States due to malaria. His conclusion is 

 that $100,000,000 per year is a fair estimate. The writer's studies 

 have convinced him that this estimate is extremely conservative. If 

 the full effects of the depreciation of land values due to the presence 

 of mosquitoes and the hindrance to development were to be taken 

 into consideration the figures would have to be raised considerably. 



Spotted fever causes about fifty deaths per year and there are about 

 four hundred cases of invalidism not resulting in death. On the 

 basis mentioned, the deaths represent a money value of $85,000 and 

 the invalidism $15,000, or a total of $100,000 annually. 



Rather exact estimates of the losses due to splenetic fever of cattle 

 have been made. A very reasonable figure which has been practically 

 agreed upon by a number of investigators is $100,000,000 per year. 



The other diseases included in the list of those transmitted solely 

 by insects, namely, typhus and dengue, are not covered by absolutely 

 definite statistics at the present time. In case of dengue it is probable 

 that many cases are included in the reports on malaria. Typhus fever 

 is of no great importance although it is probable that a surprising 

 number of cases will be found in the cities that receive a large inflow 

 of immigrants from Europe and Mexico as a recent publication of the 

 Public Health Service shows that Brill's disease is nothing but typhus. 

 In view of the absence of exact statistics it had been considered best 

 to discard these two diseases for the present. 



To summarize the losses due to diseases transmitted exclusively by 

 insects, for which statistics are available, we have: 



Malaria $100,000,000 



Spotted fever 100,000 



Splenetic fever 100,000,000 



Total $200,100,000 



We now proceed to a number of important diseases which are not 

 transmitted exclusivelj^ by insects, but by them to a greater or lesser 

 extent. These are: tuberculosis, typhoid fever, enteritis and diar- 

 rhea and dysentery. The most important of these is tuberculosis 

 which, according to Professor Fisher's statistics, causes a total loss 

 to the people of the United States of over $1,000,000,000 annually. 

 There are no data available, as far as the writer knows, which would 

 give a definite basis for estimating the proportion of deaths from tuber- 

 culosis which are chargeable to insects. Recent work on the longevity 



