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[Hymenolepis diminuta] [Hymenolepis nana]

Arthropods, especially beetles, serve as intermediate hosts for Hymenolepis spp.  The arthropod intermediate host is required for H. diminuta, but not H. nana, and humans can become infected with the latter by direct ingestion of eggs.  Within the arthropod host, the eggs develop into cysticeroids, which can infect the mammalian host upon ingestion and develop into adults in the small intestine.

A	B

A:  Tribolium confusum, a common intermediate host for Hymenolepis spp.  Tribolium and related genera breed in cereals, grains, and grain-based snack foods and are easily ingested by humans and rodents.  Since these food products are usually not heated prior to consumption, cysticeroids within the beetles remain viable and infective.  Image courtesy of Parasite and Diseases Image Library, Australia (http://www.padil.gov.au/).
B:  Tribolium castaneum, another beetle commonly found in grain products that may serve as an intermediate host for Hymenolepis spp.  Image courtesy of Parasite and Diseases Image Library, Australia (http://www.padil.gov.au/).