Identification of sparganosis based on next-generation sequencing

The incidence of sparganosis, a parasitic disease caused by plerocercoid larvae of the genus Spirometra, has gradually risen worldwide (especially in remote areas) in recent years. Pulmonary and pleural sparganosis, as well as other sites of infestation, including the subcutaneous tissues, the abdominal viscera, brain and eyes, has been reported. In clinical practice, due to the atypical signs and symptoms as well as limited laboratory approaches for the specific detection of sparganum, sparganosis is often misdiagnosed. In the present study, an 11-year-old girl visited the Department of Infectious Diseases in Shanghai Children's Medical Center for recurrent shoulder and chest pain and shortness of breath. Imaging tests demonstrated bilateral pleural and pericardial effusion, enlarged lymph nodes in front of the tracheal carina, and infection of the left lower lobe. Sparganum were not observed in the dissected soft tissue at the root of the right thigh with naked-eye and light microscopy examination. Histologic examination revealed granulomatous inflammation and tunnel-like necrosis with eosinophilic, neutrophilic and lymphocytic infiltration. Although the patient's serum was positive for sparganum antibodies, the diagnosis of sparganosis was not confirmed for more than three months. Ultimately, genomic DNA of Spirometra erinaceieuropaei was detected in the mass at the root of the right thigh using next-generation sequencing (NGS), confirming the diagnosis of sparganosis. The patient was treated with praziquantel (150 mg/kg/day) without recurrence after an eight-month follow-up. We present, for the first time, a study of human sparganosis diagnosed using NGS, which provided a clinically actionable diagnosis of a specific infectious disease from an uncommon pathogen.