Comparative development of Australian strains of Echinococcus granulosus in dingoes ( Canis familiaris dingo) and domestic dogs ( C.f. familiaris), with further evidence for the origin of the Australian syl vatic strain

Abstract

The growth and development of Australian strains of E. granulosus were compared in domestic dogs and pure-bred dingoes. The sylvatic strain, which is maintained in a cycle between dingoes and wallabies on the Australian mainland, was found to develop far more rapidly in dingoes than in dogs. Development of this strain in dogs was markedly retarded. However, domestic strains of E. granulosus originating from sheep in Tasmania and the Australian mainland developed at a comparable rate in dingoes and dogs. Dingoes were also found to be more susceptible to infection with the sylvatic strain than dogs, as evidenced by considerable differences in worm burdens. No such differences in susceptibility were seen with the domestic strains. These results not only emphasise the inherent differences between the sylvatic and domestic strains of E. granulosus, but also support previous suggestions that the strains were introduced into Australia independently. The fact that the sylvatic strain appears to be physiologically adapted to the dingo indicates that it was brought into Australia many thousands of years before the original domestic strain.