Abstract:

The pathogen identification and epidemiological analysis were conducted to a patient infected with Spirometra mansoni adult worm, who was first diagnosed as Taenia infection. Information on clinical symptoms and signs, previously received diagnosis and treatment, and dietary history and habit was collected from the patient. The patient received treatment with pumpkin seeds combined with areca for deworming. The morphological characteristics of scole, gravid proglottides and eggs expelled from the patient were observed by microscopy. The specific gene fragments of Spirometra mansoni and Diphyllobothrium latum were amplified using PCR, and the amplification products were sequenced and analyzed by BLAST. The serum antibody for Sparganum mansoni was detected with ELISA. The patient reported occasional excretion of "worms" with feces in the past four years. No dietary history of raw meat products was reported, but a history of meat barbecue was noted. ELISA results showed that the serum showed negative for Sparganum mansoni-specific antibody. A worm of 2.1 m in length was expelled, with a pair of long bothria in the scolex. The width of gravid proglottid was greater than the length, and the eggs were shaped as a long oval with an egg cap. The worm was preliminarily determined to be pseudophyllidean according to the features of worm body and eggs. PCR results showed a specific band of Spirometra mansoni, and BLAST analysis revealed a 99% homology with Spirometra erinaceieuropaei (synonym of Spirometra mansoni) (GenBank accession number: AP017668.1). The case is therefore confirmed as an infection of S. mansoni based on the clinical features, morphological characteristics of the worm, and the PCR and sequencing results.

Key words: Spirometra mansoni, Adult worm, Infection, PCR