Infection with Hymenolepis diminuta Blocks Colitis and Hastens Recovery While Colitis Has Minimal Impact on Expulsion of the Cestode from the Mouse Host

The Tapeworm Hymenolepis diminuta as an Important Model Organism in the Experimental Parasitology of the 21st Century

The tapeworm Hymenolepis diminuta is a common parasite of the small intestine in rodents but it can also infect humans. Due to its characteristics and ease of maintenance in the laboratory, H. diminuta is also an important model species in studies of cestodiasis, including the search for new drugs, treatments, diagnostics and biochemical processes, as well as its host-parasite interrelationships. A great deal of attention has been devoted to the immune response caused by H. diminuta in the host, and several studies indicate that infection with H. diminuta can reduce the severity of concomitant disease. Here, we present a critical review of the experimental research conducted with the use of H. diminuta as a model organism for over more than two decades (in the 21st century). The present review evaluates the tapeworm H. diminuta as a model organism for studying the molecular biology, biochemistry and immunology aspects of parasitology, as well as certain clinical applications. It also systematizes the latest research on this species. Its findings may contribute to a better understanding of the biology of tapeworms and their adaptation to parasitism, including complex correlations between H. diminuta and invertebrate and vertebrate hosts. It places particular emphasis on its value for the further development of modern experimental parasitology.

Hymenolepis diminuta Infection in a Romanian Child from an Urban Area

Hymenolepis diminuta is primarily a rodent parasite that is ubiquitously distributed worldwide, but with only a few cases described as human infections. We report a case of Hymenolepis diminuta infection in a 15-month-old child, living in an urban setting, with no previous medical history. The patient presented with two episodes of seizures, and complaints of abdominal pain, vomiting, and diarrhea, with no apparent history of rodent contact. Furthermore, the patient’s gastrointestinal symptoms were linked to the emission of suspected tapeworm proglottids in the feces. After excluding other possible etiologies, a diagnosis of Hymenolepis diminuta infection was made, based on the examination of characteristic eggs in a concentrated stool specimen. The infant was successfully treated with praziquantel and fully recovered. After two weeks, the stool sample was free of Hymenolepis diminuta eggs. The clinical follow-up over the next 3 years was normal. Hymenolepis diminuta is rarely found in humans, and, when present, the infection is frequently asymptomatic. Abdominal pain, irritability, itching, eosinophilia, and seizures have also been reported. In this paper, we report, for the first time in the literature, an infection with Hymenolepis diminuta in a Romanian infant who had atypical neurological presentation, with full recovery, without subsequent neurological sequelae.