10 CIRCULAR. 14 8, U. S. DEPARTMENT OE AGRICULTURE 



stomach worm, because of the tumors which they produce. The 

 tumors interfere to a considerable extent with the proper functioning 

 of the stomach. When large tumors are situated near the junction 

 of the stomach and intestine they interfere mechanically with the 

 passage of food. The most evident injury occasioned by the large 

 stomach worms is produced b} T the larvae which get into the skin of 

 horses where they are commonly associated with a skin disease known 

 as summer sores. 



Treatment. — A high degree of efficacy for the destruction of H. 

 muscae and H. microstoma has been obtained by the use of the fol- 

 lowing method of treatment. The animal should be fasted for from 

 18 to 24 hours and the stomach washed out by injecting through a 

 stomach tube 8 to 10 quarts of a 2 per cent solution of sodium bicar- 

 bonate (baking soda). The alkaline solution tends to remove the 

 thick layer of tenacious mucus which normally covers the lining of 

 the horse's stomach and renders the stomach worms more accessible 

 to the action of drugs. It is advisable, though not necessary, to 

 siphon off the sodium bicarbonate solution. If the solution is not- 

 siphoned off, an interval of 15 to 20 minutes should elapse before 

 further treatment. Carbon disulphide should then be administered 

 in capsule or by stomach tube in a dose of 6 fluid drams (21 cubic 

 centimeters) for a 1.000-pound animal, or at a dose rate of 1.5 fluid 

 drams (6 cubic centimeters) for each 250 pounds of weight. Xo 

 purgative should be used with this treatment. H. megastoma in 

 stomach tumors is not affected by this treatment and is inaccessible 

 to any method of treatment known at present. 



Prevention. — Prevention of stomach-worm infestation in horses 

 involves the storage of manure in closed containers, in order to de- 

 crease the number of flies which breed in manure, or the application 

 of other control measures designed to prevent flies from breeding. 

 The use of containers for storing manure with a view to destroying 

 eggs and larva? of parasites is discussed subsequently in this circular. 

 The United States Bureau of Entomology has devised a trap de- 

 signed to destroy fly maggots which breed in manure. The trap is 

 based on the observation that maggots, when fully grown, migrate 

 out of moist manure and if they are permitted to escape through 

 spaces between the boards of an open manure platform raised on 

 posts and set in a concrete basin of water, they are caught in the 

 basin and drowned. This and various other methods of controlling 

 the house flv and stable fly are given in Farmers' Bulletins Xos. 1408 

 and 1097. 



SUMMER SOEES 



A skin disease of horses, known as summer sores and characterized 

 by pronounced skin lesions, is associated in some pans of the world, 

 including the United States, with the larva? of the large stomach 

 worms of horses. The sores may be as small as a millet seed, but 

 are usually about the size of a pea and may attain a size about an 

 inch in diameter. The sores are covered by a soft, brownish-red, 

 pulpy material with cracks or furrows which are filled with pus. 

 In the midst of the softened mass there are small, rounded granu- 

 lations which are firm in texture. 



