Pathogenecity on experimentally infected dogs with Babesia gibsoni

Babesia gibsoni의 실험적 감염 개에 대한 병원성

This study was conducted to observe the severity of the disease and pathogenecity of Babesia gibsoni parasite on the splenectomized dogs(SPD) and nonsplenectomized(intact) dogs (NSPD) experimentally infected with B gibsoni. The average prepatent period was 4 days in the SPD and 8 days in the NSPD, respectively. Peak parasitaemia(PE) ranged from 26% to 34% of erythrocytes infected in the SPD and from 4% to 5% in the NSPD. Latent parasitaemia was still detectable 40 days as low as under 1.0% of erythrocytes infected after the initial parasitaemia in the SPD. Blood packed cell volume(PCV) decreased to as little as 6.4% to 6.9% in the SPD. The clinical signs were mild fever and anemia in the NSPD, remissions and exacervations of temperature, intermittent or spike-like increases of temperature, progressive polychromatophilic macrocytic anemia with anisocytosis, icterus, marked loss of appetite, rarely haemoglobinuria, and deep brown-yellowish urine in the SPD. Gross pathologic changes mainly involved slightly enlargement of liver and spleen in the NSPD and marked enlargement of liver in the SPD. Anatomic changes associated with the disease included diffuse periportal and centrilobular hephatitis, and membranoproliferative glomerulonephritis. Hyaline droplets, resulting protein metabolic alterations, were found in the convoluted ephithelium of the kidney. The density of lymphocytes within the liver sinusoids was markedly increased. Aggregates of large monocytes and macrophages were demonstrated in the centrilobular veins of the liver. The density of these cells in the centrilobular veins were greatest in the SPD. The forms of B gibsoni parasite found in the acute stage of SPD were large signet ring form, small signet ring form, pyriform, elongated form, comma form, head-phone form, oval form, peared form, racket-like form, amoeboid form, triangle form, quartered form, dot form, band form and multiple, and rosette form, et al. The severity of the disease and pathogenecity of B gibsoni parasite were mild in the NSPD but fatal in the SPD.