INSECTS AND DISEASE 



Insects were in the past a far more important factor in 



p. . the spread of disease than is the case today. 



~. , ~. Bubonic plague, which destroyed a quarter 



Olden Times , ,, , .- r t^ • , L -L- , i, 



of the population of Europe in the Middle 



Ages, is primarily a disease of the rat, spread from rat to rat, 

 and from rat to man by the bite of the flea. The dreaded 

 typhus fever, which once decimated jails and camps, is 

 spread by the bite of the body louse. With improvements 

 in habits of personal cleanliness these pestilences have dis- 

 appeared from civilized countries. Plague broke out in 

 1894, ravaged India, and found its way to ports all over 

 the known world, but nowhere outside of Asia could it gain 

 a foothold. Typhus was almost forgotten until the con- 

 fusion and ruin of the European War permitted its appear- 

 ance on the Eastern battle front. It is controlled by de- 

 stroying lice through rigid measures of disinfection of the 

 bodies and clothing of those who have been exposed to 

 infection. 



The most important insect carriers of disease today, out- 

 T , side of certain regions in Africa, are the fly 



V'Mh V] an( * ^ e mosc l u ^o. The common house fly 



or filth fly is only an accidental carrier of 

 such disease germs as it may happen to pick up on its feet 

 or body; but in warm climates, where excreta are improperly 

 disposed of, it is an important factor in the spread of typhoid 

 fever, and studies in New York City and Richmond, Va., 

 have shown that it may play a considerable role in distribut- 

 ing the germs of infant diarrhea. The first essential in con- 

 trolling the fly is to do away with its breeding places b}^ 

 proper care of stable manure, in which it lays its eggs by 

 preference, and by the elimination of other decaying rub- 

 bish. Manure should be stored in a closed dark bin with 

 an impervious floor and removed once a week. The tight 

 floor and complete removal are essential, since the fly mag- 



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