PCR-based identification reveals unique Southern African internal transcribed spacer (ITS) haplotypes of hookworms (Ancylostoma) of dogs from the Durban metropole, South Africa

Abstract

Previous studies on helminths of dogs have revealed a relatively high prevalence of Ancylostoma spp. in dogs in Southern Africa. Ancylostoma caninum, and to a lesser extent, A. braziliense have been reported as the predominant species in dogs based on either morphology of eggs or of adult parasites. The reliability of both methods is questionable and hence the aim of this study was to identify the species infecting dogs in the Durban metropole, South Africa, by comparing morphology of the eggs and results from a polymerase chain reaction (PCR)-based test applied to the third stage larvae of the parasites. Morphology of the egg (measurements of width and length of egg) revealed that the mean length and width of all specimens collected were compatible with A. caninum. However, phylogenetic analysis of the ITS-5.8S-ITS2 region of the DNA of third stage larvae of the same specimens revealed the presence of A. caninum and A. braziliense; the most common haplotype of each species had been previously reported, whilst the others were novel. Ancylostoma eggs were identified in 19 of the 63 dogs sampled (30%). Of these, 18 (95%) were infected with A. caninum, whereas 5 (26%) were infected with A. braziliense. Four (21%) of specimens had mixed infections of both A. caninum and A. brasiliense.

Key words: Ancylostoma spp., hookworms, dogs, Durban metropole, egg morphology, PCR, ITS sequencing.