480 HORSE POX 
Soulié and Emery have adopted an intradermic inoculation of 
diluted virus of which they report good results. Sheep cannot be 
imported from Algiers into France until they have been inoculated 
(ovination). Duclert found, in 1896, that blood serum of immune 
sheep has a protective value in lambs. Borrel recommends the 
simultaneous injection of immune serum and virulent lymph. 
HORSE POX 
Synonyms: Variola equina; vaccine du cheval; Pferde-pocke. 
Characterization. Horse pox is an exanthematous disease of the 
horse characterized by a slight febrile disturbance and the appearance 
of typical variolous eruptions. . 
History. Jenner recognized this disease near the close of the 18th 
century in the valley of the Severn. It has appeared at various times. 
in France and Germany. In 1877 an outbreak occurred in Montreal 
and was described by Dr. McEachran in the Veterinary Journal in 
August, 1877. At that time several hundred horses were affected. 
It is now considered a rare disease in horses. Many of the French 
authorities and also Hunting consider equine variola and contagious. 
pustular stomatitis to be identical. 
Etiology. The virus of horse pox is contained in the skin Jesions-. 
Infection is said to take place by contact and by articles infected from. 
diseased horses. 
Symptoms. The first symptom is that of disturbed temperature 
with an eruption on the mucous membranes of the mouth, lips or 
nasal mucosa or on the skin of different parts of the body. It usually 
appears in the hollow of the pastern. The skin becomes swollen and. 
sensitive followed by the development of the papules, vesicles and. 
pustules. It is a mild disease that runs a definite course. 
Morbid anatomy. The essential changes consist in the develop- 
ment of the lesions characteristic of variola. The lesions may be 
restricted to one limb or they may be on two or more. There may be: 
considerable swelling and suppuration of the subcutaneous tissue ac- 
cording to reports. When the lesions are on the mucous membrane of 
the mouth the vesicles are ruptured by the friction during mastica- 
tion, and small depressed erosions on the mucous membranes occur. 
Petechial hemorrhages have been reported. 
Diagnosis. Horse pox is to be diagnosed by the symptoms and. 
variolar eruptions. It is to be differentiated from the condition 
