Serological diagnosis of cystic echinococcosis in cattle.

An IgM murine monoclonal antibody (MAb) was obtained against the excretory-secretory antigen (ES-Ag) of in vitro reared protoscoleces of Echinococcus granulosus (Batsch, 1786). Western blotting revealed that the MAb recognised a 20.6 kDa protein of this ES-Ag. The MAb was used in sandwich enzyme-linked immunosorbent assay (s-ELISA) for selective sensitisation of the solid phase with the protoscolex-specific protein from its ES-Ag and somatic antigen (S-Ag) to examine serum samples of 108 cows from a cystic echinococcosis (CE) endemic area for specific antibodies and to compare the results with those from necropsies and an indirect ELISA (i-ELISA). The sensitivity of s-ELISA/ES-Ag, s-ELISA/S-Ag and i-ELISA/S-Ag was 48%, 52% and 62%, respectively. The low sensitivity of the ELISA was probably caused by the fact that 13 cows (62%) were infected with sterile cysts (acephalocysts and/or calcified foci) only. A relatively high specificity (80%) of s-ELISA/ES-Ag was observed in cows with fertile cysts. It also detected antibodies in the serum of two cows that had recovered from the disease according to the necropsy. The i-ELISA/S-Ag gave false results in testing sera from a healthy animal and from a cow with tubercular foci. Further analysis will be necessary to define more precisely the value of this study, because the duration of antibody elimination from the bloodstream of recovered cattle remains unknown. The solution of this problem will increase the specificity of the proposed test in monitoring herbivorous animals for CE.

Hematological and Serological Investigation of Dogs during Experimental Echinococcosis.

OBJECTIVES: To study the hematological findings of dogs infected with echinococcosis and the possibility of using in vitro reared Echinococcus granulosus excretory-secretory antigen (ES-Ag) as a reagent for serological diagnosis of canine echinococcosis. METHODS: Eight dogs were infected orally with protoscoleces, extracted from ovine fertile hydatid cysts. Two additional dogs were infected with Cysticercus tenuicollis, obtained from infested sheep. The hematological parameters of dogs were determined with the ADVIA 2120i automatic hematology analyzer with a blood smear staining module. Adult E. granulosus and/or Taenia hydatigena that were collected from small pieces of the open gut and the larval cestodes that were extracted from infested sheep during slaughter were cultured in an incomplete RPMI-1640 medium. The parasite-ES-Ag-containing supernatant was used as an antigen in enzyme linked immunosorbent assay (ELISA) to detect antibodies in the sera of infected dogs. RESULTS: A significant increase in hemoglobin concentration and erythrocyte count was found during the infection, as well as an increasing proportion of lymphocytes and segmented neutrophils, accompanied by a significant reduction of the leukocyte count and a growth of both the absolute and the relative eosinophil count. ELISA found a strengthening antigenicity of echinococcus preparations during infection. This property was more pronounced in the protoscoleces ES-Ag, compared to the eponymous antigen of an adult parasite. The latter gave specificity to ELISA, which allowed differentiating it from the similar antigen of the closely related tapeworm T. hydatigena. CONCLUSION: In vitro reared adult E. granulosus ES-Ag can be used as an antigen in the serological diagnosis of canine echinococcosis. Hematological parameters and serological results have predictive value in the screening of dogs for echinococcosis; however, in some individuals, they may reflect the state of resistance to invasion.