Cerebrospinal echinococcosis: serodiagnosis using different hydatid cyst fluid antigens
El-Arousy, M.H.; Ismail, S.A.
Journal of the Egyptian Society of Parasitology 35(1): 193-204
2005
ISSN/ISBN: 1110-0583 PMID: 15881006 Document Number: 592155
A study was conducted to select a suitable antigen and the most valuable serological test for serodiagnosis of cerebrospinal echinococcosis. Two groups of patients from Egypt were studied: 14 patients with symptoms suggestive of a space-occupying lesion in the central nervous system (group 1) and 26 patients with other parasitic infection diagnosed by faecal examination (group 2) . Antigens used were Eg1 (crude hydatid cyst fluid or HCF antigen), Eg2 (crude HCF antigen), Em11 (semipurified fraction of HCF antigen), Eg commercial, and a purified 44-45 kDa fraction. Three serological tests were performed: ELISA using different HCF antigens, counter-immunoelectrophoresis (CIEP) and indirect haemagglutination test (IHAT). ELISA using the Eg1 or Eg2 detected 6 of 9 positive patients, whereas the semipurified Em11 antigen and the purified 44-45 kDa antigen gave a positive reaction in 4 and 5 patients, respectively. Similar results (5 positive reactions) were obtained with the commercial antigen used in the IHA test. CIEP using the prepared crude Eg1 antigen gave 3 positive reactions. When Eg1 was used in the ELISA method at a concentration of 25 micro g/ml, it cross-reacted with 2 sera of group II, giving a specificity of 92.3%. In CIEP, Eg1 had a 100% specificity. ELISA using the Eg2 antigen gave false positive reactions with 6 sera belonging to 4 S. mansoni-infected cases and two Fasciola-infected cases, giving an overall specificity of 76.9%. EM11 and purified 44-45 kDa fraction had no cross-reaction, 100% specificity. The specificity of IHAT was 100%.