title: Ovine echinococcosis I. Immunological diagnosis by enzyme immunoassay.
abstract: Immunodiagnosis in sheep presents problems of sensitivity and specificity, limiting its applicability in surveillance systems. The objective of this study was to develop a sensitive, specific and accessible technique for diagnosing cystic echinococcosis in naturally infected sheep and to evaluate the validity of necropsy as a reference test. A total of 247 sheep were studied at slaughterhouses, confirming the parasitological diagnosis with histology. Serum was processed with enzyme immunoassay (EIA) using three antigen preparations: total hydatid liquid (LHT), purified fraction of LHT (S2B) and purified lipoprotein (B). Western Blot (WB) was used as a control. EIA proved effective for differentiating Echinococcus granulosus from larval stage of Taenia hydatigena and intestinal cestodes in all three antigen preparations. Serums from macroscopically negative sheep were reactive to EIA and positive with WB. In the whole flock, sensitivity was 89.2% for LHT, 80.0% for S2B and 86.4% for B. Sensitivity in lambs was 78.6% for LHT, 75.0% for S2B and 64.3% for B. Macroscopic diagnosis at the time of slaughter was found to have limitations as a reference test for immunodiagnosis of cystic equinococcosis in sheep, so it was necessary to include histology and WB as reference tests. LHT was the antigen preparation of greatest value and EIA proved to be a sensitive and specific technique, adequate for surveillance systems and for evaluating control programmes.
authors.affiliation: Health Ministry, Rio Negro Province, Argentina.
authors.forename: Antonio
authors.initials: A
authors.lastname: Gatti
authors.forename: Angela Rosa
authors.initials: AR
authors.lastname: Alvarez
authors.forename: Daniel
authors.initials: D
authors.lastname: Araya
authors.forename: Sergio
authors.initials: S
authors.lastname: Mancini
authors.forename: Eduardo
authors.initials: E
authors.lastname: Herrero
authors.forename: Graciela
authors.initials: G
authors.lastname: Santillan
authors.forename: Edmundo
authors.initials: E
authors.lastname: Larrieu
mesh_terms: D000003:Abattoirs; D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology; D015153:Blotting, Western / Q000662:veterinary; D003937:Diagnosis, Differential; D004443:Echinococcosis / Q000175:diagnosis / Q000662:veterinary*; D004446:Echinococcus / Q000276:immunology*; D005260:Female; D007124:Immunoenzyme Techniques / Q000379:methods / Q000592:standards / Q000662:veterinary*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018571:Sentinel Surveillance / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000175:diagnosis*; D013621:Taenia / Q000276:immunology
chemical_list: D000947:Antigens, Helminth