Diagnostic Laboratory Section

Protozoa Demonstrable in blood smear

PROTOZOA DEMONSTRABLE IN LEISHMAN-GIEMSA STANIED SMEARS

Pathogen	Specimen used for smear	Appearance in stained smear
Babesia canis	Blood (thin smear)	Blue, pear-shaped organisms, singly or in pair in erythrocytes
Hepatozoon canis	Blood (thin smear)	Rectangular blue-staining organisms (3 x 6 µm) with reddish nuclei in neutrophils
Trypanosoma spp	Blood (thin smear) Buffy coat (thick smears), lymph node aspirate or ascitic fluid	Long, flattened, spindle shaped trypomastigote (15-20 mm in length) forms, with central nucleus, an undulating membrane and a free flagellum, free in the blood, extracellular
Theileria annulata	Thin blood smear	Small rings, rods and commas in single or multiple are found in RBCs. Organisms stain bluish purple
Kochs Blue Bodies	Lymph node aspirate smear	Schizonts (KBB) appear as roundish multineucleate structure in the cytoplasm of lymphoid cells. Organisms stain bluish purple
Ehrlichia spp	Blood smear	Morula stage (purple colour) in monocytes and lymphocytes
Anaplasma sp	Blood smear	Bright dots with a tendency to be located centrally or marginally. They may have a faint halo around them.

Interpretation of thin blood smear

• 1-10 parasites/100 field = + (mild)
• 11-100 parasites/100 field = + + (moderate)
• 1-10 parasites/field = + + + (severe)
• >10 parasites/field = + + + + (very severe)