480 DISEASES OF THE HOESB. 



Parasite: Psoroptes egm {De'rmatocoptes eqm, Dermatodectea 

 equi). Malady: Psoroptic acariasis. — Psoroptic mange is less com- 

 mon than sarcoptic mange in horses, and as the parasite (PI. XXXIX, 

 fig. 3) only bites the surface and lives among the crusts under the 

 shelter of the hair, it is very easily discovered. It reproduces itself 

 with equal rapidity and causes similar symptoms to those produced by 

 the Sarcoptes. The same treatment will suffice and is more promptly 

 effectual. The purifying of the stable must be more thorough, as the 

 Psoroptes will survive twenty to thirty days in the moist atmosphere 

 of a stable, and may even revive after six or eight weeks when sub- 

 jected to moist warmth. Infested pastures will therefore prove dan- 

 gerous to horses for that length of time, and, with rubbing posts, etc., 

 should not be used. 



Parasite: Chorioptes equi {Symbiotes equi, Dermatophagus equi, 

 Chorioptes spatMferus) . Malady: Foot imange. — ^The acarus (PI. 

 XXXIX, fig. 2) attacks the heels and lower parts of the legs, espe- 

 cially the hind ones, and may be present for years without extending 

 upon the body. Like the Psoroptes, it lives on the surface, on the 

 hairs, and among the scabs. It gives rise to great itching, stamping, 

 rubbing of the one leg with the othjer, and the formation of papules, 

 wounds, ulcerous sores, and scabs. The intense itching will always 

 suggest this parasite, and the discovery of the acarus will identify 

 the disease. The treatment is the same as for the Sarcoptes, but 

 may be confined to the legs and the parts with which they come in 

 contact. 



Parasite : DerniMnyssus goMinm, or chicken acari. Malady : Poul- 

 try acariasis. — ^This is a large-sized acainis, though usually miscalled 

 "hen louse," and the disease "poultry lousiness." The mite (PI. 

 XXXIX, fig. 4) lives in droppings and in crevices of chicken houses, 

 but temporarily passes on to the skin of man and of the horse and 

 other quadrupeds, when occasion serves. It causes much irritation, 

 with the eruption of papules or vesicles and the formation of sores 

 and scabs. The examination of the skin is usually fruitless, as the 

 attacks are mostly made at night and the effects only may be seen 

 during the day. The proximity of hen manure swarming with the 

 acari explains the trouble, and the removal of this and a white- 

 washing with quicklime, with or without chlorid of lime, will prevent 

 future attacks. The skin may still require bland ointments or 

 lotions, as for congestion. 



Parasite : Larva of a Tromhidium,, Leplms americamMS, or harvest 

 lug, misnamed jigger (chigoe). Malady: Autum/n mmige. — ^This 

 parasite is a brick-red acarus, visible to the naked eye on a dark 

 ground, and living on green vegetation in many localities.. It attacks 

 man, and the horse, ox, dog, etc., burrowing under the skin and giving 

 rise to small papules and intolerable irritation. This continues for 



