36 PREVENTION 
pharyngeal cavity. In these cases the animal becomes emaciated. 
The lesions in these cases resemble somewhat those of chronic gland- 
ers. Many complications are liable to arise. Mixed infections and 
secondary lesions often occur. The prognosis, however, is favorable. 
Death from strangles is caused usually by either septicemia, 
pyemia, pleuritis, peritonitis or suppurating (metastatic) pneumonia. 
The duration of the disease varies according to its severity and the 
localization of the lesions. In mild cases convalescence begins in a 
few days, but in other cases restoration may redjuire weeks and even 
months. 
The mortality, according to available statistics, does not exceed 
four per cent. In certain epizodtics it may be higher. Often it is 
below two per cent. 
Diagnosis. Strangles is to be diagnosed by the symptoms, 
lesions and a bacteriological examination. There are no specific 
tests that can be used for its detection. Strangles is to be differen- 
tiated from the following affections, namely: 
Purulent nasal catarrh. In this affection, there are rarely suppu- 
rating sub-maxillary glands, although occasionally these glands may 
be swollen. 
Glanders. In glanders, the tissue changes are more persistent 
and the skin lesions, if they exist, do not heal as rapidly as in strangles. 
In chronic cases, the diagnosis is quite difficult. Here animal inocula- 
tion must be resorted to. Mice inoculated subcutaneously with the 
nasal discharge succumb to the streptococcus of strangles but they 
are resistant to the bacterium of glanders. Guinea pigs inoculated in 
a like manner will, in case of glanders, develop that disease from the 
lesions of which pure cultures of Bacterium mallet may be obtained. 
The specific tests for glanders may be applied. 
Parotiditis. In this affection the swelling is localized in the 
parotid gland and suppuration does not often occur. 
Abscesses due to pyogenic bacteria. The cases are rare where 
there would be any question as to diagnosis. The bacteriological 
examination including the inoculation of animals would give positive 
aid unless the pyogenic organism happened to be a virulent streptococ- 
cus in which case a differentiation might be difficult. In these cases 
the nasal mucosa is not likely to be involved. 
Prevention. This is best obtained by isolating the infected horses 
and removing the well ones from the infected premises. Colts are 
