February, '13] HUNTER: medical entomology 35 



example, the expenses arising from quarantines. The precautions 

 that are taken against the introduction of yellow fever, cholera and 

 other epidemic diseases are large, to say nothing of the expense of the 

 control of plague which is already introduced in this country. 



It must also be borne in mind that we are only beginning to acquire 

 definite knowledge regarding insects which transmit diseases. The 

 extent to which this is done in cases where something is known about 

 transmission is probably greater than we believe, and, moreover, 

 we must consider the possible discovery of insect causation of diseases 

 which are not at present included in the category of those borne by 

 insects at all. It was but yesterday that the connection between 

 poliomyelitis and the stable fly was discovered and no one knows what 

 addition to our knowledge will be made tomorrow. 



The extent to which the importance of insect disease transmitters 

 seems certain to increase can be realized by considering poliomyelitis. 

 The statistics relating to this disease are very unsatisfactory on account 

 of the apparently great increase in the number of cases within the 

 last few years. The latest statistics available give the deaths from 

 this malady in 1909 as 569 in the registration area of the United States 

 which represented at that time 55.3% of the total population of the 

 United States (Frost Public Health Bulletin 44, page 8). The same 

 authority gives statistics which indicate an average death rate of 

 7.7% If we estimate the number of cases from the non-registration 

 area in proportion to those in the registration area in the United States 

 (it may be incorrect on account of the greater occurrence of the disease 

 in the northeastern part of the country where practically all of the 

 states are in the registration class), and use the mortality rate men- 

 tioned, we find an annual loss for the United States in the value of 

 lives of $1,734,000. The 13,000 cases of invalidism suggested by these 

 statistics would represent a money loss of $10,404,000, or a total from 

 the disease of $12,138,000. If insect transmission transpires to be as 

 important as the work of Brues and others indicate, at least one tenth 

 of the cases may originate through the attacks of Stomoxys calcitrans. 

 This would add over a million dollars annual loss to the estimate we 

 have given. 



In all of these estimates we have omitted, altogether, an important 

 group of incidental expenses that is chargeable to insects. This con- 

 cerns the warfare that is waged throughout the country against num- 

 erous species which are merely nuisances and not, as far as known,, 

 concerned in the transmission of diseases. The house fly and various 

 non-pathogenic mosquitoes are combated by various mechanical 

 devices, such as screening, the expense of which, as Doctor Howard- 

 has pointed out, probably aggregates ten million dollars annually. 



