Strongyloides Genetic Diversity among Humans, Dogs, and Nonhuman Primates, Central African Republic, 2016-2022.

Strongyloides stercoralis nematode infection occurs in ≈600 million persons worldwide and is listed by the World Health Organization as a neglected tropical disease. Understanding zoonotic potential is critical, especially in areas where humans, domestic animals, and wildlife interact. We explored cross-species sharing of Strongyloides roundworms by analyzing fecal samples from humans, dogs, and nonhuman primates in the Dzanga-Sangha Protected Areas, Central African Republic. We detected positive samples by quantitative PCR and assessed genetic diversity through amplification of the 18S rRNA HVR-IV region and cox1, followed by high-throughput sequencing. Strongyloides prevalence was high in humans, dogs, and gorillas. S. stercoralis haplotype A roundworm dominated in humans but appeared in dogs and apes, whereas S. fuelleborni roundworm was present in all hosts. Shared species and haplotypes indicated zoonotic transmission. Our findings highlight the need for molecular surveillance and emphasize the role of dogs and nonhuman primates as reservoirs, complicating efforts to control infections in human populations.