Frequency of lentz bodies inclusion in erythrocytes of whole blood and expanded buffy coat smears

ABSTRACT

Background: Canine distemper has been classified as highly contagious for most of domestic and wild carnivores, and theinfection can be fatal. Canine distemper inclusion bodies, also denominated Lenz inclusion bodies, are large aggregatesof viral nucleocapsid particles that can be form in red blood cells (RBCs), white blood cells (WBCs) and epithelial cellsin many tissues during the acute phase of infection. Their presence in blood is transient and rarely encountered in lightmicroscopy but are pathognomonic when identified in blood smears. The objective of this study was to investigate thefrequency of distemper inclusions in erythrocytes according to the fraction of the sample used for blood smears.Materials, Methods & Results: The study was conducted with routine blood sample provided by the Veterinary Laboratory of Clinical Analysis from the Veterinary Teaching Hospital of Universidade Federal do Rio Grande do Sul. TheEDTA-K2 blood sample of a 40 days old male dog, mixed breed, no immunization records, presenting diarrhea, hyporexia,myoclonus and pustules in the abdomen, was selected. In a routine peripheral blood smear examination, several distemperinclusions were observed in the erythrocytes. From this sample, ten smears were performed using a whole blood (WB)and top erythrocyte fraction combined with buffy coat, denominated of expanded buffy coat (EBC). The EBC fraction wasobtained after centrifugation of EDTA whole blood in microhematocrit tubes at 9600 g for 5 min to obtained the packedcell volume (PCV) and buffy coat. After centrifugation, the blood cells are separated into three layers based on densityplatelets (adjacent to supernatant), WBCs, and RBCs in the bottom. The PCV was measured and the microhematocrit tubewas ruptured 2% below the interface between leukocytes and plasma, deposited into a plastic microtubes, homogenized andused for blood smear preparation. All smears were stained with Diff-Quick Stain...