Babesia bovis DETECTION FROM CAPILLARY BLOOD IMPROVES DIAGNOSIS IN CARRIER CATTLE

GUILLEMI E; DE LA FOURNIERE S; SARMIENTO N; FARBER M; WILKOWSKY S. E

Mar del Plata

Congreso; X Congreso de Protozoologia y Enfermedades Parasitarias; 2014

Sociedad Argentina de Protozoologia

Babesia bovis infects bovine erythrocytes turning their membrane more rigid than in normal cells. This fact determine that B. bovis parasitized erythrocytes tend to be retained in capillary vessels. Besides, carrier cattle show undetectable parasitemia in blood smears turning into low sensitivity of detection by direct methods using venous blood The aim of this work was to improve B. bovis identification by comparing DNA detection from capillary and venous blood in carrier cattle. Blood from three cows suffering chronic babesiosis were sampled from two different anatomic areas: jugular vein and capillary vessels.Venous blood was extracted by syringe and conserved in heparinized tubes. Capillary blood was obtained by pricking the tip of the tail with a needle and collected in Whatman papers. DNA was extracted from a drop of capillary blood and from 100 μl of venous blood by the phenol-chloroform method. For capillary blood, a previous step was needed for retrieving blood from the paper by pre-incubating the paper in lysis buffer. After the incubation, the supernatant was used for standard phenol-chloroform DNA extraction. DNA from capillary and venous blood was analyzed by an end point PCR and a quantitative PCR (qPCR); both reactions targeted simple copy genes: rip9 and rcc respectively. For the end point PCR, B. bovis DNA was detected in both capillary and venous samples of the three animals with a higher intensity of the amplification band in the capillary samples in all cases. For the qPCR, two capillary samples showed higher DNA copy numbers than the venous samples, although the latter had value levels below the detection threshold. These results suggest that B. bovis DNA detection from capillary blood is a much better approach for diagnosis in carrier cattle.