Identification and histopathological assessment of intestinal Hymenolepis nana in pet hamsters in Guiyang, China

Hymenolepis nana (H. nana) is a zoonotic parasite with a global distribution. Hamsters are a common household pet and have been widely domesticated. H. nana is a prevalent tapeworm that parasitizes the small intestine of hamsters. However, there are few recent reports on whether pet hamsters in urban areas are infected with H. nana and the morphological characteristics of different developmental stages of the parasite. This study employed a combination of morphological and molecular biological approaches, utilizing pathological staining to investigate the helminth infection of pet hamsters in Guiyang, China, and the subsequent histopathological damage it caused. The results confirmed the presence of H. nana, and its average infection rate was as high as 256/359 (71.31 %), revealing that its different developmental stages exhibit distinct parasitic sites. Cysticercoids were found to parasitize the intestinal villi, while adult worms resided in the intestinal lumen, with the latter causing more severe pathological damage. Our study updates data on the prevalence of H. nana in Guiyang, China, as well as the morphological characteristics of H. nana at various developmental stages and the associated histopathological changes in the small intestine of pet hamsters.