Eighty one liver cyst fluid samples obtained by fine needle aspiration biopsy (FNAB) in human patients were examined for specific E. granulosus
antigen 5 (Ag5). The patients were suspected cases of hepatic
cystic echinococcosis (CE) but protoscolices and hooks had not been found in the
cyst bioptates. Presence of Ag5 was tested for using
enzyme linked immuno-sorbent assay (ELISA) technique with
monoclonal antibody against Ag5. Sensitivity of the test was approximately 1 ng of
antigen/1 ml of examined fluid. Positive results were obtained in the control group of six patients having protoscolices and/or hooks in biopsy samples from liver
cysts. Positive Ag5 results were also obtained in the samples from 89 fertile
cysts and 28 sterile
cysts originated from 15 naturally infected pigs as an experimental control group. Ag5 was present in nine cases (11.1%) out of 81 liver cyst fluid samples from suspected CE patients. In 25 human patients the sensitivity of the microscopic examination for protoscolices and/or hooks in FNAB material was 64% (16/25). In pig
hydatid cysts the sensitivity of the microscopic examination for protoscolices and/or hooks in FNAB material was 86.5% and of the detection of Ag5-100%. In conclusion, examination of hepatic
cyst biopsy samples for specific Ag5 resulted in increased detection of liver
echinococcosis in human patients.