Abstract
The patient was a Brazilian woman in her 40s. She consulted the department of general medicine at our hospital after a white, motile, and several centimeters long worm was found in her stool. The genus and species of the worm could not be identified. Therefore, we consulted an expert through Aichi Association of Medical Technologists. The worm was presumed to be a proglottid of the genus Taenia based on its morphological characteristics. We then performed a genetic test for identifying the species and estimating the origin of infection. Morphological observation revealed a genital pore located laterally. Injecting with India ink into the pore demonstrated uterine branches in the worm body. Next, Taenia eggs, which had a brown and radial embryophore, were detected by microscopic examination of liquid containing worm cut into small pieces. Furthermore, DNA was extracted from the worm, amplified by PCR and subjected to sequencing analysis, which confirmed the worm to be Taenia saginata. Next, the extracted DNA was compared with worldwide data by performing phylogenetic tree analysis; however, since the extracted DNA sequence was short, we could not estimate the origin of infection. Experience and knowledge have been limited about parasites because of decreasing the number of infections with parasites and examination. It is often the case that Identifying the genus and species is difficult based on morphological features. In this scenario, genetic testing is an extremely useful tool for species identification.
