Hematological and Serological Investigation of Dogs during Experimental Echinococcosis

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.

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.

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.

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.