42 VETERINARY PARASITOLOGY 
Filaria Irritans. 
This parasite in the larval state causes a disease of 
the skin known as “ parasitic granular dermatitis,” or 
“summer sores.” The parasite is found in South 
Europe, Algeria, and India. It becomes surrounded by 
a calcareous capsule, and remains in the skin all 
the summer. Probably it gains entrance from the 
surface. 
The nodules are commonest on the parts normally 
covered with harness, and probably friction plays a 
part in introducing the parasite. 
Treatment.—Sulphide of arsenic has been successfully 
used. 
Phenol or iodoform collodium are of service. 
Dracontiasis. 
In India, Africa, Egypt, Persia, and South America, 
the guinea-worm (Fularia Medinensis) sometimes lives 
in the skin of the horse, dog, or cow. 
It is a large worm, and buries itself in the connective 
tissue. In time one end emerges through an orifice in 
the skin, and the Indians then remove it. It is stated 
that if the worm is broken in the process, death of the 
patient at once follows, but this is open to grave 
doubt. 
Embryos are set free by the rupture of the body of 
the worm, and pass this stage of their existence inside 
small crustaceans. After some while they are taken 
into the body of one of the larger animals during the 
act of drinking, and reach the stomach, where fertiliza- 
tion takes place. The males then die, and the females 
bore to the surface. 
Fleming has recorded chronic lameness in horses 
caused by this parasite. 
