58 Deai't of Law fob the Prevention op Infectious Anemia. 



within ten days. In lighter cases or when horses have 

 more or less acquired immunity, the final issue may 

 follow a sudden febrile attack which occurs on the 40th- 

 50th day, or in several months or even several years. In 

 some it was observed that the animal was able to per- 

 form ordinary work without any dangerous symptoms. 



The virus may live for several years after the 

 patient has apparently recovered and nothing abnormal 

 is observed. 



Excepting in acute cases, the patient will improve 

 by care in the stable, rest from work, nutritious rations 

 etc. and will eventually recover. Those recovered horses 

 have some degree of resistance, so that even if a large 

 quantity of the virulent blood is inoculated into them 

 they will not show any symptoms of the disease, although 

 they carry the virus for a long time. 



Etiology. — The disease is caused by an ultra- 

 microscopic organism, which passes through the clay- 

 filter. It is as yet impossible to cultivate the virus 

 artificially. 



It is transmitted mainly by horse-flies (.Tabanidae) 

 in the field. The infection can be induced experiment- 

 alily per os. 



Symptoms. — The disease begins with a febrile attack. 

 The main symptoms are abnormality in palpitation, pulse, 

 and visible mucous membrane. In light cases, the tem- 

 perature does not rise above 39°C., but in severe form, 

 it reaches over 41°C. In many cases the temperature 

 falls to normal in a short time. One or two weeks or 

 several weeks after, another exacerbation comes. Then 

 comes another and so on. With each recurrence of the 

 febrile attacks, the animal gradually falls into an anemic 

 condition. But in some cases, the patient shows 

 symptoms of anemia from the incipient stage. In the 



