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Molecular characterization of Hymenolepsis nana infecting human in Sohag, Egypt.

Amal Mostafa Ahmed*, Nada Abd El Fattah El Nadi, Asmaa Kamal Abd Ellah, Noha Sammer Ahmed

Background: Hymenolepis nana is the most common cestode in humans, rats and mice. It is not clear whether H. nana found in humans is the same species found in rodents or whether they are two distinct species morphologically identical yet genetically distinct. Objective: To identify the genomic diversity of H. nana human isolates in Sohag, to determine their transmission patterns and to construct the phylogenetic tree to assess the evolutionary relationship of H. nana human and rodent isolates. Methods: 20 H. nana positive stool samples were collected from outpatients? children referred to Sohag hospitals. Genomic DNA was extracted from stool samples. Mitochondrial cytochrome C Oxidase subunits 1 (COX1) gene of H. nana human isolates were amplified, sequenced and analyzed phylogenetically. The phylogenetic trees were reconstructed by neighbor joining and maximum likelihood methods based on COX1 gene of H. nana human isolates obtained in this study and the known H. nana human and rodent isolates published in GenBank. Results: All 20 H. nana isolates were successfully amplified and sequenced at the COX1 and produced 5 different COX1 gene sequences. The NJ and ML phylogenetic tree showed almost similar topology which suggested that H. nana human isolates of present study were closely related which means they came from the same origin, were more related to H. nana infecting human especially Latin America due to migration, differed notably from rodent isolates of previous studies which support that rodent to human is less likely to happen and were different from human isolate of Australia. This is explained by evolution in Australian isolates due early separated from rest of the world. Genetic differences were found 0.6% to 4% between human isolates of present study and rodent isolates of previous studies. The annotated sequences of our Egyptian isolates were deposited in GenBank of NCBI under the following accession number; MT093851, MT093852, MT093853, MT093854 and MT093855. Conclusions: The Phylogeny of the COX1 suggested that H. nana is a species complex or cryptic species (morphologically identical yet genetically distinct) and the life-cycle of H. nana that exists in Sohag is likely to Involve mainly human to human transmission.