PARASITES AND PARASITIC DISEASES OF HORSES imi 
This disease has been studied in Europe, Africa, and elsewhere, 
where it has been noted that its seasonal occurrence corresponds to 
the prevalence of flies. It is unlikely that the worm larve invade 
the unbroken skin, but it appears to be well established that when a 
horse’s skin is broken by some injury and when flies which carry 
the worm larvee feed on the sores, the larvee escape from the mouth 
parts of the fly and live for a time in the wounds. These larve irri- 
tate the sore, so that instead of healing as a simple sore it may 
become a more or less chronic thing which does not heal until after 
the occurrence of frost in the fall. 
Although conditions known as “summer sores” in horses are 
known to occur in the United States, the disease has not been exten- 
sively studied here and the relation of stomach-worm larve to sum- 
mer sores still needs further investigation in this country. Recently 
the occurrence of the larval worms from summer sores in horses in 
the United States has been definitely reported. 
Treatment for summer sores—An astringent powder which is said 
to prevent the extension of the trouble and to aid in healing consists 
of the following: Plaster of Paris, 100 parts; alum, 20 parts: ; naph- 
thalene, 10 parts; and quinine, 10 parts. 
Good results are reported from the use of a caustic paste composed 
of arsenious oxide, 1 part, and flour, 5 parts. Washing the sores with 
ether or chloroform and then painting them with collodion has also 
been recommended. Some veterinarians prefer the use of a 5 to 10 
per cent solution of formalin, applied by means of a cotton pad 
which is left on the sores for two to three hours every day 
Prevention.—Skin injuries should be protected from His by the 
use of pine-tar oil or other means to prevent their conversion into 
summer sores. 
THE SMALL STOMACH WORM 
This parasite, 7’rchostrongylus axet, occurs in the lining of the 
stomach, and is likely to be overlooked unless one is especially on the 
lookout for it. The worms are very slender and are about one-fifth 
of an inch or less in length. 
Life history.—The life history of this parasite has not been defi- 
nitely ascertained. Im a general way its life history is similar to 
that of blood strongyles, described elsewhere in this circular, with 
respect to the development of the eggs and larvee on pastures. It is 
also fairly certain that infestation is direct, and results from the 
swallowing, by horses, of the infective larve with food or water. 
However, these worms burrow only into the stomach wall and are 
not known to wander extensively, as young worms, throughout the 
body of the horse. 
Symptoms and lesions——Because these parasites occur embedded 
in the lining of the stomach, they injure the stomach wall. Some- 
times the stomach hning shows areas superficially like a ringworm 
or a mass of small tumors. (Fig. 5.) In addition to their injuries 
to the stomach wall, these parasites ne ibute to the general picture 
of gross parasitism in horses which is characterized by weakness, 
paleness of the mucous surfaces, wasting, and digestive disturbances. 
Treatment.—Treatments for the removal of this parasite are sim- 
ilar to those recommended for the large stomach worms, 
