Failure to infect laboratory rodent hosts with human isolates ofRodentolepis(=Hymenolepis)nana

Abstract

AbstractConfusion exists over the species status and host-specificity of the tapewormRodentolepis(=Hymenolepis)nana. It has been described as one species,R. nana, found in both humans and rodents. Others have identified a subspecies;R. nanavar.fraterna, describing it as morphologically identical to the human form but only found in rodents. The species present in Australian communities has never been identified with certainty. Fifty one human isolates ofRodentolepis(=Hymenolepis)nanawere orally inoculated into Swiss Q, BALB/c, A/J, CBA/CAH and nude (hypothymic) BALB/c mice, Fischer 344 and Wistar rats and specific pathogen free (SPF) hamsters. Twenty four human isolates ofR. nanawere cross-tested in flour beetles,Tribolium confusum. No adult worms were obtained from mice, rats or hamsters, even when immunosuppressed with cortisone acetate. Only one of the 24 samples developed to the cysticercoid stage inT. confusum; however, when inoculated into laboratory mice the cysticercoids failed to develop into adult worms. The large sample size used in this study, and the range of techniques employed for extraction and preparation of eggs provide a comprehensive test of the hypothesis that the human strain ofR. nanais essentially non-infective to rodents.