COPROANTIGEN DETECTION IN DOGS EXPERIMENTALLY AND NATURALLY INFECTED WITH ECHINOCOCCUS-GRANULOSUS BY A MONOCLONAL ANTIBODY-BASED ENZYME-LINKED-IMMUNOSORBENT-ASSAY

A sandwich ELISA for the detection of Echinococcus granulosus coproant igen in formalin and heat-treated faecal supernatants of dogs was deve loped. The assay used affinity-purified polyclonal antibodies obtained from rabbits hyperimmunised with E. granulosus excretory/secretory an tigens and biotinylated monoclonal antibody EmA9 produced against adul t E. multilocularis somatic extract. The test was sensitive to 7 ng an d 2.3 ng of E. granulosus protein and carbohydrate/ml of faecal supern atant, respectively. Thirteen helminth-free dogs were infected with di fferent amounts of E. granulosus protoscoleces and the presence of cop roantigen was monitored during the prepatent period until day 35 post- infection, when they were necropsied. Faecal antigen levels started to rise above the normal range between days 10 and 20 post-infection, an d typically peaked at the end of the experiment. All the dogs, bearing from 3 to 67 700 worms, showed positive values in the ELISA during th e prepatent period. One dog experimentally infected with Taenia hydati gena metacestode and harbouring three worms, tested positive only afte r the prepatent period at day 52. The test was applied to 98 stray dog s. The ELISA detected all of four dogs naturally infected with E. gran ulosus, two dogs with patent infections of T. hydatigena and two dogs with no cestode infections, showing a sensitivity of 100% and a specif icity of 96%. (C) 1997 Australian Society for Parasitology. Published by Elsevier Science Ltd.