Study On Fasciola Gigantica Experimental Infection In Water Buffalo

Immune responses to Fasciola gigantica experimental infection in Water Buffalo and liver pathological changes of the hosts were studied. Ten Water Buffaloes about 6-month-old were randomly divided into 2 groups of 5. Group A (marked with A₁, A₂, A₃, A₄, A₅) served as control, Group B (marked with B₁, B₂, B₃,B₄,B₅) was experimentally infected by oral administation with F. gigantica 250 metacercariae (MC). All animals were bled from the jugular vein weekly for blood samples for 19 weeks post-infection (19 WPI). Whole white blood cells (WBC), differential white blood cells were count (DC) and serum preparations were carried out on the collected blood samples. The antibody titres of the sera of animals were determinated using ELISA. Feacal samples were collected from the rectum of amimals and examined for F. gigantica eggs by sedinentation method from the 7th week post-infected (7 WPI). All animals of Group B were necropsied at 19 WPI. The livers of animals were dissected for recovery and measurement of flukes. The results showed that no clinical symptoms in Group A and Group B during the experiment. The whole white blood cells (WBC) count increased in Group B, but the differences between Group A and Group B were not significant statistically. No significan differences between Group A and Group B in monocyte, basophil, and neutrophil counts were observed. The eosinophil count in Group B increased significantly from 4 WPI. Anti FgESP-IgG level increased significantly at 2 WPI and displayed a peak at 17 WPI in Group B. The recoveries of flukes in B1, B2, 83, B4, B5 were 22.4%, 4.4%, 16.8%, 13.2%, 24.4% of infection dose respectively. The mean recoveries was 16.2±8%. In Group B, flukes eggs were found starting at 13 WPI in one animal and at 14 WPI for the other 4 animals. No flukes eggs were found in Group A during the experiment. Pathology was observed in the appearance of the livers of certain animals. The pathological slice showed that the livers had being repaired, and the lesions were replaced by leucocytes and fiberes.