Insights into Infant Strongyloidiasis, Papua New Guinea.

The human-infecting parasite Strongyloides fuelleborni subspecies kellyi has been reported from the island of New Guinea. We analyzed fecal DNA extracts (n = 164) from 19 infants in Papua New Guinea by using Strongyloides real-time PCR and undertook metabarcoding of cox1 and 18S rRNA hypervariable regions I and IV loci. Eight infants were infected with Strongyloides spp.; 7 were infected with S. fuelleborni subsp. fuelleborni and 1 with a Strongyloides sp. previously misattributed to S. fuelleborni subsp. kellyi. Phylogenetic and haplotyping analyses indicated S. fuelleborni in Papua New Guinea belongs to the Indochina subclade of S. fuelleborni subsp. fuelleborni and is not a unique subspecies. We report molecular evidence of S. fuelleborni subsp. fuelleborni infection in humans in the Pacific. Our findings also demonstrate the potential co-existence of an undescribed human-infecting Strongyloides sp. on the island of New Guinea, indicating a need for renewed clinical and epidemiologic investigations into infant strongyloidiasis.