Differentiating Taenia solium and Taenia saginata infections by simple hematoxylin-eosin staining and PCR-restriction enzyme analysis

Species-specific identification of human tapeworm infections is important f or public health purposes, because prompt identification of Taenia solium c arriers may prevent further human cysticercosis infections (a major cause o f acquired epilepsy). Two practical methods for the differentiation of cest ode proglottids, (i) routine embedding, sectioning, and hematoxylin-eosin ( HE) staining and (ii) PCR with restriction enzyme analysis (PCR-REA), were tested on samples from 40 individuals infected with T. solium (n = 34) or T aenia saginata (n = 6). Microscopic examination of HE staining of sections from 24 cases, in which conserved proglottids were recovered, clearly revea led differences in the number of uterine branches. Distinct restriction pat terns for T. solium and T. saginata were observed when the PCR products con taining the ribosomal 5.8S gene plus internal transcribed spacer regions we re digested with either AluI, DdeI, or MboI. Both HE histology and PCR-REA are useful techniques for differentiating T. solium from T. saginata. Impor tantly, both techniques can be used in zones of endemicity. HE histology is inexpensive and is currently available in most regions of endemicity, and PCR-REA can be performed in most hospital centers already performing PCR wi thout additional equipment or the use of radioactive material.