A previously healthy Chinese male returned from Equatorial Guinea presenting with migratory masses. He was diagnosed with loiasis following detection of Loa loa by nested polymerase chain reaction using DNA extracted from tissue. Loiasis is an infection caused by the nematode Loa loa, which belongs to the Filariodea family. Because of global movement of travelers and workers, this disease may be occasionally encountered in regions where
it is not endemic and may be misdiagnosed. Here, we report a case of loiasis in a Chinese patient that was diagnosed by a nested polymerase chain reaction (PCR) using DNA extracted from soft tissue biopsy as template. A 35-year-old male patient was admitted to West China hospital with migratory masses present near
his wrists Epacadostat clinical trial and ankles for more than 8 weeks and feeling movement find more of a worm in his right eye for 3 days. Physical examination on admission revealed only slight swelling of his right wrist although skin color was normal. In the following days, the swelling mass migrated to a location nearby. The “moving worm” in his right eye could not be observed by the naked eye, and ultrasonography was performed, revealing spots of low density in the vitreous body. Blood tests revealed anti-hepatitis C virus antibodies, a slightly increased lactate dehydrogenase level (558, reference range 110–220 IU/L), and eosinophilia [white blood cell (WBC) count, 19.75 × 109 L−1; eosinophil cells, 70.0%; and lymphocytes, 12%]. Hepatitis C viral load was 1.0 × 103 copy/mL. Serological tests by ELISA were positive for Evodiamine IgG-type antibodies for Echinococcus spp., Taenia solium, Angiostrongylus
cantonensis, Trichinella spiralis, Clonorchis sinensis, and Schistosoma japonicum. Neither parasite ova nor larvae were visible on examination of stool. No microfilariae were detected in the peripheral blood by microscopic examination of thick blood films collected during the day or at midnight. As these results were unable to provide a final diagnosis and the right calf became swollen 8 days after hospitalization, ultrasonography of the right calf was therefore conducted, which revealed a pipeline-shaped lesion (Figure 1). No worms were found on surgical excision and examination of this mass. Histopathological examination of the calf biopsy specimen, the surrounding skin, and subcutaneous tissue revealed only chronic inflammatory cell infiltration, mainly consisting of eosinophils. The patient had been working in Equatorial Guinea for 13 months before returning to China 4 months prior to this presentation. Onchocerca volvulus and L loa infections are known to be endemic in Equatorial Guinea and loiasis was therefore suspected. No microfilariae were detected, and treatment with diethylcarbamazine (DEC) was initiated with a dosage regime of 50 mg on the first day, 50 mg three times on the second day, 100 mg three times on the third day, and followed by 150 mg three times daily for 18 days.