Apr. 3,1925 Investigations of Infectious Equine Anemia 689 
Fig. 8—Temperature record of animal No. 2796 
and in horses affected with other dis¬ 
eases. They are especially numerous 
in the blood of horses used for the 
production of hemorrhagic septicemia 
antiserum. Later developments may 
show that they are peculiar to this 
disease or that they are some form of 
antibody or immune body. Their 
presence in greater numbers in the 
blood of the hyperimmune horses 
would tend to confirm this. In this 
connection further observations will 
be of value. 
DIAGNOSIS 
Too much emphasis can not be laid 
on the fact that the only positive 
differential diagnosis of infectious ane¬ 
mia is by the reproduction of it in a 
susceptible animal. Sometimes, how¬ 
ever, a fairly accurate diagnosis can 
be made from a physical examination, 
including a blood count. If the case 
can be observed for a few days in order 
to get a temperature curve this is also 
a great help. From the writer's 
observations the two conditions most 
likely to be confused with the disease 
are parasitisms and nonspecific second¬ 
ary anemias. The differentiation from 
parasitisms has been mentioned pre¬ 
viously. That of nonspecific anemias 
requires considerable care and judg¬ 
ment but is apparently less difficult, 
for as a rule, some contributing factor 
can be found. 
Usually the autopsy lesions are of 
some help in diagnosing the disease. 
In general, there is an enlargement of 
the . spleen, a peculiar brownish, gran¬ 
ular condition of the liver, the latter 
being very friable, and in many cases 
there are extensive epicardial and 
endocardial hemorrhages. 
TRANSMISSION 
Little work has been done here on 
the methods by which the disease is 
spread. Carre and Vall4e (1, 2, S, 4) 
and others believe that it is spread by 
19977—25t-7 
urine, feces, and other body discharges, 
contaminating the food and drink of 
healthy horses. Scott (12, 13, 14 , 15, 
16, 17) has apparently proved that 
flies spread the disease. From the 
investigations made by the writer it 
seems highly probable that flies are 
an important factor in its dissemination. 
When material was available, a healthy 
horse was put with the sick; they ate 
from the same manger, drank from the 
same tub, and were kept in intimate 
association with one another. This 
experiment was repeated several times, 
Fig. 9—Temperature record of animal No. 2676 
so that there is little chance that an 
animal which was naturally resistant 
would be used in every instance. One 
horse was kept for over 16 months in 
continual contact with the sick ones. 
None of the experimental animals 
showed any evidence of having con¬ 
tracted the disease. It is of interest to 
note that there were few, if any, biting 
flies present where these animals were 
kept. 
One should not overlook the import¬ 
ant fact that the disease is most 
prevalent in the season of the year 
when biting and sucking flies are most 
abundant, namely, the late summer and 
fall. If one can take a small quantity 
