38 CIRCULAR 148, U. S. DEPARTMENT OF AGRICULTURE 
Fumigating horses with the fumes from burning sulphur (sulphur 
dioxide) will kill horse lice, but many of the eggs survive, and two 
treatments two weeks apart are necessary to effect eradication. The 
advantage of this method of treatment is that it can be used when 
the weather is too cold for dipping. The disadvantages are that it 
is necessary to have a gas-tight inclosure and the animal’s eyes and 
nostrils must be kept away from the gas. <A concentration of about 
1 per cent sulphur dioxide is necessary to kill the parasites, and 
serious injury or 
death may result if 
the gas comes in con- 
tact with the eyes or 
nostrils. After fu- 
migation it is neces- 
sary to hand treat 
that part of the head 
that was not fumi- 
gated. (Fig. 26.) 
HORSE MANGE 
Scabies in_ horses, 
commonly known as 
mange, itch, or scab, 
is a Name given to a 
group of contagious 
skin diseases caused 
by minute parasites 
known as mites, which 
live on or in the skin. 
Four species of these 
parasites are found on 
domesticated animals, 
but horses are com- 
monly affected by 
only ees of them. 
These parasites are 
classified zoologically 
in three different 
genera — Sarcoptes, 
Psoroptes, and Cho- 
rioptes. Mites of the 
FIGURE 20 rst DueaeD with suphur Bas for eee yes first two genera are 
and nostrils must be kept away from the gas. art o 2 . as 
head not fumigated must be hand treated shown in Figures 27 
and 30. 
In obtaining their food from the host and preparing a resting 
place in or on the tissues, the mites cause wounds or lesions in the 
skin. As each kind of mite possesses distinctive habits, the location 
and nature of the lesions in the early stages are more or less charac- 
teristic. Each kind of mite, therefore, causes a specific kind of 
mange which is named after the generic name of the mite. Thus we 
have in horses sarcoptic, psoroptic, and chorioptic mange. The sar- 
coptic variety is the one most common on horses in the United States. 
t) 
