• Hymenolepiasis is the most common intestinal tapeworm infection of humans caused by worm of family cestoda, genus Hymenolepis and species nana . (medscape.com)
  • In addition, the cysticer-coid stages of H nana can also invade and develop in the human intestine thus is capable of completing its entire life cycle in the human host. (medscape.com)
  • H nana can also be transmitted through autoinfection without having to pass through the insect host. (medscape.com)
  • Life cycle of Hymenolepis nana. (medscape.com)
  • Eggs of Hymenolepis nana are immediately infective when passed with the stool and cannot survive more than 10 days in the external environment (1). (medscape.com)
  • It has slightly bigger eggs and proglottids than H. nana and infects mammals using insects as intermediate hosts. (wikipedia.org)
  • Hymenolepiasis is caused by two cestodes (tapeworm) species, Hymenolepis nana (the dwarf tapeworm, adults measuring 15 to 40 mm in length) and Hymenolepis diminuta (rat tapeworm, adults measuring 20 to 60 cm in length). (cdc.gov)
  • Hymenolepis nana is the most common cause of all cestode infections, and is encountered worldwide. (cdc.gov)
  • Hymenolepis nana and H. diminuta infections are most often asymptomatic. (cdc.gov)
  • Some zoonotic helminth infections cause minimal to no symptoms in humans (eg, Dipylidium caninum , Hymenolepis nana ), whereas others, particularly those that migrate throughout the body, can cause serious, life-threatening disease (eg, Baylisascaris procyonis , Trichinella spp, Toxocara spp). (medscape.com)
  • Another less frequent zoonotic intestinal tapeworm infection is caused by H diminuta , commonly known as the rat tapeworm, in which humans are incidental hosts. (medscape.com)
  • Hymenolepis diminuta, also known as rat tapeworm, is a species of Hymenolepis tapeworm that causes hymenolepiasis. (wikipedia.org)
  • In a behavioral study of the beetle Tenebrio molitor with cysticercoids of the rat tapeworm H. diminuta, findings suggested that the parasite impairs a beetle's ability to conceal itself. (wikipedia.org)
  • Hymenolepis diminuta is a tapeworm that can cause intestinal infection in humans. (msdmanuals.com)
  • When eggs are ingested by an arthropod intermediate host (2) (various species of beetles and fleas may serve as intermediate hosts), they develop into cysticercoids, which can infect humans or rodents upon ingestion (3) and develop into adults in the small intestine. (medscape.com)
  • When ingested, the eggs develop into cysticercoids. (wikipedia.org)
  • As the definitive host (rats) eats an infected arthropod, cysticercoids present in the body cavity transform into the adult worm. (wikipedia.org)
  • Due to a lack of formal trials of the effects in humans of taking Hymenolepis diminuta cysticercoids (HDC), anecdotal reports from users and their suppliers are all that we have to go on at the present time. (helminthictherapywiki.org)
  • Hymenolepis diminuta infection in humans is rare, typically occurring in isolated cases. (wikipedia.org)
  • Hymenolepis diminuta is a cestode of rodents infrequently seen in humans and frequently found in rodents. (cdc.gov)
  • Humans can serve as definitive hosts after eating food containing infected grain insects. (msdmanuals.com)
  • Filarial nematodes that use humans as the definitive host are usually identified by the finding of microfilariae in blood or skin snips. (medscape.com)
  • fraterna , infects rodents and uses arthropods as intermediate hosts. (medscape.com)
  • Eggs of Hymenolepis diminuta are passed out in the feces of the infected definitive host (rodents, man) (1). (medscape.com)
  • Rodents, especially rats, are definitive hosts and natural reservoirs of H. diminuta. (wikipedia.org)
  • In rural Devghar, India, a place heavily infested with rodents and cockroaches, H. diminuta eggs were found in a 12-year-old girl living in a small village. (wikipedia.org)
  • Rodents (primarily rats) serve as the definitive host of H. diminuta and beetles (flour and grain beetles) serve as the intermediate host. (msdmanuals.com)
  • Since data regarding praziquantel treatment of H. diminuta is sparse, scientists have recommended that every case and treatment of H. diminuta be reported for development of protocols and parasitological purposes. (wikipedia.org)
  • This infection does not require an intermediate host and infection can occur directly from one infected person to another by fecal-oral transmission. (medscape.com)
  • An alternate mode of infection consists of internal autoinfection, where the eggs release their hexacanth embryo, which penetrates the villus continuing the infective cycle without passage through the external environment (9). (medscape.com)
  • H. diminuta infection is acquired by the mammalian host after ingestion of an intermediate host carrying the cysticercoid larvae (4). (medscape.com)
  • Prevalence of Hymenolepis diminuta infection in man in the New Guinea Highlands. (wikipedia.org)
  • Human infection with Hymenolepis diminuta : Case report from Spain. (wikipedia.org)
  • Marangi M, Zechini B, Fileti A, Quaranta G, Aceti A. Hymenolepis diminuta infection in a child living in the urban area of Rome, Italy. (wikipedia.org)
  • Hymenolepis diminuta Infection in a Child from a Rural Area: A Rare Case Report. (msdmanuals.com)
  • [ 1 , 2 ] Although this is also true for zoonotic helminths, it is important to note that the site(s) of infection and clinical manifestations may differ from what is observed in the natural animal host. (medscape.com)
  • Eggs are passed in the stool when released from proglottids through its genital atrium or when proglottids disintegrate in the small intestine (8). (medscape.com)
  • The resulting eggs are then passed through the stool. (wikipedia.org)
  • Figure E: Egg of H. diminuta in an unstained wet mount of concentrated stool. (cdc.gov)
  • Diagnosis is by finding characteristic eggs in stool. (msdmanuals.com)
  • Most helminths that colonize the human intestinal tract are identified by the gross morphology of adult worms or proglottids in stool specimens, or the identification of eggs and larvae in ova and parasite (O&P) examinations of stool. (medscape.com)
  • Secondly, if the parasites do not mature to adults or reproduce in the human host, traditional diagnostic methodologies, such as O&P examinations of stool or examination of blood films, may not be appropriate. (medscape.com)
  • The mature eggs are ingested by an intermediate host (various arthropod adults or larvae) (2), and oncospheres are released from the eggs and penetrate the intestinal wall of the host (3), which develop into cysticercoid larvae. (medscape.com)
  • Species from the genus Tribolium are common intermediate hosts for H. diminuta . (medscape.com)
  • Arthropods are then able to act as the intermediate host. (wikipedia.org)
  • The intermediate hosts are the coprophilic arthropods (fleas, lepidoptera, and coleoptera). (wikipedia.org)
  • the life cycle does not require an intermediate host. (msdmanuals.com)
  • Most parasitic species have multihost life cycles, involving a vertebrate definitive host and 1 or more invertebrate or vertebrate intermediate hosts. (medscape.com)
  • Hymenolepis diminuta has been cited as a possible candidate species for helminthic therapy, i.e. the controlled use of live organism parasites for the prevention and control of diseases of modern living. (wikipedia.org)
  • When two species of worm are introduced together by someone who has not previously hosted helminths, or not hosted for some time, the initial immune response may be excessive and the risk of side effects greatly increased. (helminthictherapywiki.org)
  • approximately 1% of paediatric patients experienced severe gastrointestinal pains with the use of H. diminuta, although the symptoms were resolved with an anti-helminthic drug. (helminthictherapywiki.org)
  • It also provides a brief description of the taxonomy, biology and life cycle, epidemiology, route of transmission for the human host, clinical manifestations, pathologic features, treatment, and laboratory diagnosis for these organisms. (medscape.com)
  • Microscopic examination of urine samples to detect parasite eggs still remains as definitive diagnosis. (nih.gov)
  • Overall, the training experiment portrayed that infected beetles were unable to hide from the rat, illustrating the high impact the parasite had on its host, the beetle. (wikipedia.org)
  • When eggs are ingested (4) (in contaminated food or water or from hands contaminated with feces), the oncospheres contained in the eggs are released. (medscape.com)
  • In recent findings, beetle-to-beetle transmission of H. diminuta can be seen via the feces. (wikipedia.org)
  • Hymenolepis diminuta , while less frequent, has been reported from various areas of the world. (cdc.gov)
  • Eggs are released in the small intestine from gravid proglottids (7) that disintegrate after breaking off from the adult worms. (medscape.com)
  • In this review, we apply the term zoonotic to those parasites that usually complete their natural cycle in the absence of a human host. (medscape.com)
  • Pinworms can be identified in cross-section by their characteristic lateral alae (arrows, below), and the presence of the eggs in gravid females. (blogspot.com)
  • These eggs are round or slightly oval, size 70 - 85 µm X 60 - 80 µm, with a striated outer membrane and a thin inner membrane. (cdc.gov)
  • Additionally, more infections occur due to this mechanism of egg dispersal. (wikipedia.org)
  • As such, several studies of H. diminuta exist as case reports describing a single affected individual. (wikipedia.org)
  • In 1989, a child from St. James Parish, Jamaica was the subject of the first documented case of H. diminuta occurring in Jamaica, West Indies. (wikipedia.org)
  • In this case, these eggs have classic features of Taenia eggs, including small size (approx 30 microns diameter), thick wall with radial striations, and beautifully defined internal hooklets. (blogspot.com)
  • This is why we always try to coax eggs out of possible worms that are submitted to the laboratory for identification. (blogspot.com)
  • Note that the egg in the image still contains an unhatched larva. (blogspot.com)
  • The nymph had just hatched from an another egg (not shown). (blogspot.com)
  • The presence of eggs is very useful in cases where the morphologic features of the gross object are indistinct. (blogspot.com)
  • Some diagnostic features which are nicely demonstrated in the appendix cross-sections include alae, intestines, ovaries, and the hard-to-mistake eggs (which I think look like little loaves of bread). (blogspot.com)