Hammondia triffittaen. comb. of foxes (Vulpesspp.): biological and molecular characteristics and differentiation fromHammondia heydorniof dogs

Abstract

SUMMARYGenomic DNAs from 3 oocyst isolates ofHammondiasp. from foxes (Vulpes vulpesandV. lagopus) and 1 oocyst isolate ofHammondia heydornifrom a dog, were examined by PCR and sequence analysis of 6 loci in order to determine whether the isolates were conspecific. Consistent genetic differences were found between the fox and dog isolates, respectively, at the ITS-2 region, the lsu rRNA gene, the alpha tubulin gene and the HSP70 gene, but not at the ssu rRNA gene or ITS-1 locus. Infection experiments established that dogs were unsuitable as definitive hosts forHammondiasp. of foxes; hence this species is regarded as separate fromH. heydorniof wolf-like canids, but probably identical withIsospora triffittae(syn.Isospora triffitti) previously reported from foxes. This species has therefore been namedHammondia triffittaen. comb. Reindeer, moose, sheep, goats, foxes and rabbits may act as intermediate hosts forH. triffittae. Muscle tissues of inoculated intermediate hosts were infectious for foxes from 16 days post-infection. Oocysts ofH. triffittaewere subspherical, averaging 12·5×10·9μm in size. The lsu rRNA gene and the alpha tubulin gene seem to be suitable genetic markers for differentiating betweenH. triffittaeandH. heydorni.