evaluation of dot immunogold filtration assay (digfa) by recombinant protein epc1 for anti- echinococcus granulosus igg antibody.

background: cystic echinococcosis is an important zoonosis caused by the echinococcus granulosus with a substantial impact in human and animal health in en-demic areas. the purpose of the present study was serodiagnosis optimizing of dog echinococcosis in order to achieve a rapid diagnostic method. methods: eight dogs were challenged with protoscoleces in order to have posi-tive echinococcosis serum and 2 two-month old puppies were used as uninfected controls. colloidal gold was prepared by controlled reduction of a boiling solu-tion of chloroauric acid (h [aucl4]) with sodium citrate and labeled with recom-binant epc1. dot immunogold filtration assay (digfa) was developed by coat-ing repc1 labeled colloidal gold on nitrocellulose membrane. the canine sera, taken three times including, 15, 28 and 35 days post infection were tested. a total of 30 serum samples including 24 sera from 8 infected dogs and 6 sera from 2 puppies were comparatively detected with both digfa and elisa. results: gold labeled antigen, showed a dark purple dot with agglutination parti-cles in positive sera and light purple dot without agglutination in negative sera. among 30 serum samples, 23 were positive and 7 were negative with digfa and 24 were positive, 6 were negative with elisa. conclusion: digfa as a rapid and simple procedure could be utilized in quickly diagnosis of echinococcosis.