Production of Hymenolepis diminuta in the Laboratory: An Old Research Tool with New Clinical Applications.

Abstract

Hymenolepis diminuta, the rat tapeworm, was first described in 1819 by Rudolphi and was studied extensively in several laboratories during the mid to latter part of the twentieth century. More recently, the primary use of the organism had been for educational purposes. The organisms require an intermediate insect host to complete their life cycle, making them non-transmissible to other rats or to humans under typical laboratory or educational environments. The organisms effectively colonize rats, but not humans or mice, and are easily maintained in laboratory. They are, with exceedingly rare exceptions, benign (e.g., nonparasitic) in humans, mice, and laboratory rats. Although the benign character of the helminth makes it ideal for educational purposes, the fact that no pathology is associated with colonization has led to decreased interest in the H. diminuta as a model for modern research where efforts are largely motivated by interests in medicine and health. However, more recently work with the "biota alteration" model of inflammatory disease has established that reintroduction of helminths into Western society, a practice often referred to as "helminthic therapy," is potentially a way of lowering inflammation without compromising immune function. For this effort, the lack of pathology and benign nature of the organism makes H. diminuta an ideal subject for study. In this chapter, we describe production of H. diminuta using laboratory rats and introduction of the organisms into laboratory mice as a model for their effects in humans.