EQUINE | Disease
impression smears is usually high and parasites are
easily demonstrated in histological sections.
Diagnostic Procedures
Blood smears: thick and thin blood smears collected
from superficial skin capillary’s from live animals is still
the primary diagnostic procedure for the diagnosis of
acute clinical piroplasmosis in equines. Even in some
clinically affected animals parasitemia is are low and
therefore smears need to be thoroughly examined. In
clinical T.equi infections parasitemia is usually between
1 to 5%, but in severe cases can exceed 20%, while in
B.caballi clinical cases parasitemia rarely ever exceeds
1%. Identification of carrier animals by examination of
peripheral blood smears is not possible. Blood smears
made from fetuses aborted due to Theileria equi
infection usually have an extremely high parasitemia.
Figure 4: Kidney – Giemsa stained section demonstrating multiple
intraerythrocytic Theileria equi parasites (arrows). Fibrin
microthrombosis evident in a glomerular capillary (*)
Figure 5. Equine fetuses aborted due to in utero Theileria equi infection.
Note the diffuse yellow discoloration (icterus) with splenomegaly and
hepatomegaly
Figure 3: Kidney from an adult horse that died of acute Theileria
equi infection. Hematoxylin and eosin stained histological section
demonstrating hemoglobinuric nephrosis with hemoglobin casts within
some renal tubules (arrow)
Organ tissue impression smears (kidney, liver, lung,
bone marrow, cerebral cortex, lymph node) from post
mortal tissues, or a practical and simple procedure
for confirming the diagnosis at post-mortem. Again,
impression smears made from fetal tissues aborted
due to Theileria equi usually have an extremely high
parasitemia. PCR has emerged as a useful tool in
• Volume 20 Issue 1 | April 2018 •
11