Molecular identification of Hypoderma sinense cutaneous myiasis in a child from a cattle-raising pastoral region of China: a case report

Abstract

Human cutaneous myiasis caused by Hypoderma sinense is rarely reported and may be mistaken for common bacterial skin disease. A 3-year-old boy from a livestock-raising pastoral region of China presented with multiple painful subcutaneous nodules that had not responded to topical antibacterial treatment. Marked eosinophilia, elevated total IgE, and linear ultrasonographic structures raised suspicion of parasitic infestation. A larva was removed intact from the posterior neck lesion through a pre-existing punctum under local anesthesia. Whole-genome shotgun sequencing followed by de novo assembly generated a 16,888-bp mitochondrial contig containing a complete COI barcode region, supporting identification of the larva as H. sinense. At the one-month follow-up, the pain and subcutaneous nodules had resolved. This case highlights the importance of considering cutaneous myiasis in children from livestock-raising regions with painful, treatment-resistant subcutaneous nodules and demonstrates the diagnostic value of ultrasonography, minimally invasive larval extraction, and molecular identification.