ABSTRACT
Definitive hosts of the Echinococcus granulosus [E. granulosus] parasite are carnivores such as dogs, wolves and foxes. Detection of this parasite through faecal examination is not possible. In this study, dot-blotting test for E. granulosus-specific coproantigens has been evaluated in dog. Three 2-3-month-old puppies were treated with piperazine and then faecal samples were collected as pre-infection samples. Seven days later, hydatid cysts from livers and lungs of sheep were fed to the puppies. Faecal samples were collected weekly for five weeks as post-infection samples. Soluble protein of pre- and post-infection faecal samples were prepared and dot-blotting test was conducted. In parallel experiments, the presence of E. granulosus eggs and also dot-blotting test were evaluated in 15 faecal samples of dogs collected from Razi Veterinary Hospital in Mashhad. For the detection of protein bands in pre-infection and fifth-week post-infection samples, polypeptide profile was analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis [SDS-PAGE]. The results showed that incremental spot colours was observed in samples of experimentally infected dogs collected from the first to fifth post-infection weeks. In dot-blot analysis of faecal samples in 15 dogs, 4 samples were positive, and also these four samples were positive for E. granulosus eggs. In SDS-PAGE, one band in pre-infection and four bands in fifth-week post-infection samples were observed. The molecular weight of pre-infection sample of experimentally infected dogs was 16 kDa and the molecular weights of the samples collected five weeks post-infection were 14, 22, 36 and 45 kDa, respectively. In conclusion, the results of this experiment showed that the dot-blotting method does not produce a reliable outcome. For evaluation of the specific coproantigens of E. granulosus in dogs, coproantigen-ELISA test is needed
ABSTRACT
In this study, the immunogenicity of three types of antigens [hydatid fluid, protoscolices and whole body of E. granulosus] was investigated in lambs by ELISA. Sixteen 4-6-month-old lambs of mixed sexes were divided into 4 groups of 4 lambs [three immunized and one control group]. Twelve lambs as immunized groups received 2 mg of hydatid fluid, protoscolices and whole body of E. granulosus antigens dissolved in 1 ml of PBS per immunization for each lamb, respectively. As an adjuvant, Freund's complete adjuvant [FCA] was mixed with antigens to form a water-in-oil emulsion which was inoculated subcutaneously on day 1 of the trial. Each control lamb was inoculated with a total of 2 ml of PBS emulsified in equal volumes of FCA. Lambs were boosted on day 28 with the same preparation as described above except that FCA was replaced by Freund's incomplete adjuvant [FIA]. Three weeks after the second immunization, each lamb received a challenge infection with 2000 protoscolices intraperitoneally and also 10 gravid proglotid of E. granulosus orally. Sera were collected before and after immunization and serum antibodies were tested by ELISA. The results showed that the production of antibody had a significant difference between the test groups and the control [P<0.05]. Lambs immunized with whole body of E. granulosus showed the highest antibody production. The level of antibody production between the lambs immunized with hydatid fluid and the protoscolices was not different significantly [P>0.05], whereas, the level of antibody production between the lambs immunized with hydatid fluid and whole body of E. granulosus was different significantly [P<0.05]. The results of this study showed that the antigens of whole body of E. granulosus might be a good candidate for immunization and diagnosis of hydatid cyst in the intermediate hosts of E. granulosus