Molecular taxonomic characterisation of Ancylostoma spp. and Strongyloides spp. in three protected areas in Ghana.

Abstract

Background: Soil-transmitted helminths (STHs) continue to affect millions of people worldwide, but the role of animals in sustaining transmission remains poorly understood. This study examined the diversity and zoonotic potential of hookworms and Strongyloides across humans, dogs, and nonhuman primates (NHPs) in three different study areas located in three ecological zones in Ghana, where humans live in close contact with domestic dogs and free-ranging nonhuman primates, creating opportunities for cross-species parasite exchange.

Methods: Stool samples from humans, dogs, and nonhuman primates were analysed using the Baermann technique after faecal culture. Single larvae and young adult worms were genotyped at the nuclear small subunit (SSU) Hypervariable Regions (HVR) I and IV, ITS-2 and the mitochondrial cox-1 markers. Species identities and genetic relationships were explored using Neighbour-joining and Maximum-likelihood phylogenies in MEGA 12 and a Median-joining haplotype network in POpART.

Results: Two major clusters of hookworms were detected in our study area, both belonging to the genus Ancylostoma. One cluster is closely related to a species group containing A. caninum, A. duodenale, A. ceylanicum, and A. tubaeforme. The other cluster appears to belong to the species A. braziliense. Several haplotypes in both clusters were shared between humans and dogs, indicating active zoonotic transmission. For Strongyloides, humans carried S. stercoralis, monkeys carried S. fuelleborni, and in dogs we found a Strongyloides that appeared closely related to S. papillosus.

Conclusions: Our findings reveal substantial hookworm diversity but no evidence for host specificity, which suggests zoonotic transmission at the human-dog interface. The, based on previous literature, unexpected recovery of A. braziliense larvae from human stool suggests that the zoonotic potential of this species may be greater than previously assumed. In contrast to several recent studies in Asia, we found no overlap between Strongyloides spp. in humans and animals but the number of Strongylodies spp. infected hosts was very small. Our results reinforce the need for including animals that live in close proximity to humans in STH studies and control considerations, following a One Health approach.