Equine Health Update EHU Vol 20 Issue 01 - Page 11

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