Travelers Returning to Denmark with Hypereosinophilia and Ancylostoma Infections Detected Using Broad-Specificity Amplicon-Based Next-Generation Sequencing.

In nonendemic countries such as Denmark, hookworm infections in travelers may be rare and difficult to detect because of low-grade shedding of parasite eggs and a lack of clinical suspicion and relevant diagnostic capacity. Two cases of hookworm infection observed in 2025 that were detected only through amplicon-based next-generation sequencing (NGS) of fecal DNA are presented in the current study. Both infections were characterized by hypereosinophilia and acquired during 2-week holidays in Asia. Case 1 was infected with Ancylostoma ceylanicum during a holiday in the Philippines, and Case 2 acquired infection with Ancylostoma duodenale/caninum in Thailand. Eggs were found only in Case 2, and only after careful reexamination. These cases reveal that amplicon-based NGS is a simple and useful diagnostic adjunct when routine parasite screening triggered by eosinophilia and abdominal pain after tropical exposure fails to establish the diagnosis. Both cases were treated with ivermectin and albendazole, respectively, with good effect.