Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 10 1 2015 03 15 30 8 EN Somayeh Kordafshari Dept. of Parasitology, School of Veterinary Medicine, Tehran University, Tehran, Iran. Seyed Hossein Hosseini Dept. of Parasitology, School of Veterinary Medicine, Tehran University, Tehran, Iran. Fatemeh Jalousian Dept. of Parasitology, School of Veterinary Medicine, Tehran University, Tehran, Iran. Masoumeh Rajabibazl Dept. of Clinical Biochemistry, School of Medicine, Shahid Beheshti University, Tehran, Iran. Malcolm Jones Dept. of Parasitology, School of Veterinary Sciences, Queensland University, Queensland, Australia. Fazeleh Etebar Dept. of Parasitology, School of Veterinary Medicine, Tehran University, Tehran, Iran. 2015 10 14   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. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/355 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/355/420