38 PARASITES OF THE DOMESTIC ANIMALS 



Habits and Relation to Disease. — While, so far as known, the 

 house fly is not an essential host to pathogenic organisms of man and 

 the mammalian domesticated animals, it is, by its structure and filthy 

 habits of feeding, one of the most dangerous of disease-transmitting 

 insects. Omniverous in habit, it will feed upon decaying vegetable and 

 putrid animal matter, excrement, vomit, sputum, or other revoltingly 

 filthy material. Direct from such sources of infection it may pass to 

 the food upon our tables to which it is equally attracted, ■ leaving a 

 trail of contamination wherever it may drag its filthy parts. 



From the viewpoint of the bacteriologist it would seem superfluous to 

 discuss the house fly as a carrier of disease-producing bacteria. The 

 form of its proboscis, habit of regurgitating its food, its six bristly feet 

 (Fig. 8), each terminated by a sponge-like structure secreting a sticky 

 substance, together with the vile material which it visits, make it both 

 by structure and habit an ideal transmitter of such infectious diseases as 

 typhoid fever, dysentery, cholera, glanders, anthrax, and ophthalmia. 

 Furthermore, positive evidence of the degree to which this insect is a 

 carrier of bacteria has been well set forth by laboratory experiment. 



Control. — As a widely disseminated menace to public health the 

 house fly presents a problem that can only be successfully dealt with by 

 community action. The measures taken should look to control rather 

 than elimination, the latter, however desirable, being scarcely possible 

 under present conditions. While it prefers horse manure, it is known 

 that almost any fermenting material will serve as a breeding place, and 

 it therefore follows that, in order to successfully combat this pest through 

 its sources of propagation, all such material must be systematically re- 

 moved, screened off, or so treated as to render it unsuitable for the 

 development of the larvae. Manure should be removed at least once a 

 week, and if possible at once spread upon the fields. Kitchen garbage 

 should be likewise removed, and in the meantime kept in tightly closed 

 receptacles. Access of flies to the vaults of outhouses can be prevented 

 by their proper structure and screening. 



Protection. — As to measures of protection to the household against 

 flies, there is little to be said that is not of common knowledge. The 

 first of these to be mentioned is the thorough screening of doors and 

 windows. Kitchens being especially attractive to flies, they should be 

 doubly protected by screening the back porch, the screen doors at these 

 locations being well fitting and made to withstand their frequent use. 

 Flies that have gained entrance are best gotten rid of by burning pyre- 

 thrum powder. A good method for the treatment of a room is to sprinkle 

 the powder upon a hot shovel after first closing the doors and windows; 

 if the kitchen, the powder may be sprinkled over the stove. It is best 

 applied at night, leaving the room tightly closed. In the morning the 

 flies will be found lying about dead or stupefied, when they may be 



