Although the transmission of cancer is a surprising event, this is. In this article we will discuss about hymenolepis nana. The infiltrate around the tumor was composed mainly of eosinophils and neutrophils. Hymenolepis nana dwarf tapeworm parasites in humans. Although the cells were unrecognizable as tapeworm tissue, immunohistochemical staining and probe hybridization labeled the cells in situ. Description of hymenolepis microstoma nottingham strain. It requires only one host but can also cycle through two. The authors cite some ear lier cases as examples of proliferating. The fact that an intermediate host is not required in the life cycle was determined in the late 1800s. Hymenolepis nana, also known as dwarf tapeworm, is a cyclophyllidean tapeworm with embryonated eggs.
The dwarf tapeworm, or hymenolepis nana, is the most common tapeworm in humans. Hymenolepis nana is the most common cestode parasite of humans in the world roberts and janovy, 2000. Hymenolepis nana infection is observed in households with poor hygiene and overcrowding, and can have a prevalence of 525% in children 54. Hymenolepiasis is an infection caused by hymenolepis nana h. In human adults, the tapeworm is more of a nuisance than a health problem, but in small children, many h. Rodents are the primary definitive hosts, and grain beetles, fleas, or other insects feed on contaminated rodent droppings as intermediate. Eggs hatch in the duodenum, releasing oncospheres, which penetrate the mucosa and come to lie in lymph channels of the villi. When eggs are ingested by an arthropod intermediate host various. Malignant transformation of hymenolepis nana in a human host to the editor. Malignant transformation of hymenolepis nana in a human. When eggs are ingested by an arthropod intermediate host various species of beetles and fleas may serve as intermediate hosts, they develop into cysticercoids, which can infect humans or rodents upon. Drugs used to treat dwarf tapeworm infection hymenolepis nana the following list of medications are in some way related to, or used in the treatment of this.
It is also known as the dwarf tapeworm due to its particularly small size adults are only 1540 mm long. A polymerasechainreaction pcr assay targeting eukaryotes identified hymenolepis nana dna. The worms mature into a life form referred to as a cysticercoid in the insect. Hymenolepiasis is infestation by one of two species of tapeworm.
Hymenolepis diminuta infection infectious diseases msd. Hymenolepis diminuta is a tapeworm that can cause intestinal infection in humans. Hymenolepis nana is the smallest of all tapeworms found in humans and is appropriately described as the dwarf tapeworm. Hymenolepis nana human diagnosed through colonoscopy. Hymenolepiasis is primarily caused by the cestode tapeworm species, hymenolepis nana the dwarf tapeworm, adults measuring 15 to 40 mm in length. Hymenolepis diminuta are greater than 30 cm in length and hymenolepis nana are less than 6 cm in length. Original article from the new england journal of medicine malignant transformation of hymenolepis nana in a human host.
This infection does not require an intermediate host and infection can occur directly from one infected person to another by fecaloral transmission. It is the smallest and only cestode that parasites the human without any intermediate host. Humans, rodents most common tapeworm of humans in the world 1% rate of infection in the southern u. For precise diagnosis of the species, molecular techniques such as pcr and rflp of. The adult worm resides in the ileal portion of the small intestine.
Apr 20, 2015 hymenolepiasis is the most common intestinal tapeworm infection of humans caused by worm of family cestoda, genus hymenolepis and species nana. Development hymenolepis nana life cycle infection is acquired most commonly from eggs in the feces of another infected individual, which are transferred in food, by contamination. Hymenolepis worms live in the intestines of rats and are common in warm climates, and are generally found in the feces of rats, which are consumed by their secondary hostsbeetles. Tumours consisting of tapeworm cancer cells found in human. Hymenolepis nana is also known as the dwarf tapeworm. Although other methods are available that can be used to distinguish hymenolepis diminuta from hymenolepis nana, an evaluation of adult size is the most convenient, not requiring specialized training for evaluation of the morphology of. It lodges itself in the intestines and absorbs nutrients from the intestinal lumen cameron, 1956. The adult tapeworm parasitizes the small intestine of. Hymenolepis nana bilharz, 1851 ransom, 1901 1 dwarf tapeworm hymenolepis nana, also known as rodentolepis nana, vampirolepis nana, hymenolepis fraterna, and taenia nana is a cosmopolitan species though most common in temperate zones, and is one of the most common cestodes a type of intestinal worm or helminth infecting humans. Hymenolepis nana has been called the dwarf tapeworm and has a worldwide distribution.
This cestode belongs to a large family known as hymenolepididae. The hymenolepis nana commonly known as the dwarf tapeworm and the hymenolepis diminuta commonly known as the rat tapeworm. It is often referred to as the dwarf tapeworm due to its small size, 24 cm long and only 1 mm wide 1 fig. Praziquantel, adults and children, 25mgkg in a singledose therapy alternatives. On the inner membrane are two poles, from which 4 to 8 polar filaments spread out between the two membranes. This infection does not require an intermediate host and infection can occur directly from one.
Malignant transformation of hymenolepis nana in a human host. Causal agent, life cycle, and geographic distribution. Hymenolepis nana, the dwarf or dwarf mouse tapeworm, is a small tapeworm in humans, sometimes found in great numbers in the intestine. Clinicopathological studies on spontaneous hymenolepis. Nov 04, 2015 the dwarf tapeworm, or hymenolepis nana, is the most common tapeworm in humans. It is the first known case of a person becoming ill from cancer cells that arose in a parasite in this case, hymenolepis nana, the dwarf tapeworm. The morphologic features and invasive behavior of the cells were characteristic of cancer, but their small size suggested a nonhuman origin. Given the widespread distribution and medical implication of members of the genus hymenolepis, specific identification of the aetiological agent becomes imperative. Nov 04, 2015 invasion of human tissue by cancer like hymenolepis nana cells larry m. He recovered a countless number of them at a postmortem on a boy who had died of meningitis.
Hymenolepis nana, a tiny intestinal tapeworm, is the most common human cestode. Hymenolepis rodentolepis nana is the most common cestode of humans, particularly in young children. Cancer is a highimpact disease throughout the world. The disease is a type of helminthiasis which is classified as a neglected tropical disease. Dwarf tapeworm nanos means dwarf, up to 40 mm long. In this study we examined the intestinal mucosa of an adult asymptomatic patient harboring adult and larval dwarf tapeworms hymenolepis nana who. Routine histology and immunohistochemistry were performed to characterize the hosts response to the parasite. Larval and adult beetles but optional larval stage, cysticercoid, can develop in d. Hymenolepis nana is a human tapeworm that can complete its life cycle in the small intestine.
Hymenolepiasis is the most common intestinal tapeworm infection of humans caused by worm of family cestoda, genus hymenolepis and species nana. It is often referred to as the dwarf tapeworm due to its small size, 24 cm long and only 1 mm wide. Areas of endemicity up to 26% prevalence include asia, southern and eastern europe. Hymenolepis microstoma dujardin, 1845 blanchard, 1891, the mouse bile duct tapeworm, is a rodentbeetlehosted laboratory model that has been used in research and teaching since its domestication in the 1950s. This parasitic worm is most frequently passed on through eggs in the faeces of another. Eggs of hymenolepis nana are immediately infective when passed with the stool and cannot survive more than 10 days in the external environment. Hymenolepis nana is the most common tapeworm in humans. The dwarf tapeworm was found in man for the first time by bilharz, in cairo, egypt, in 1851. Alternative names are dwarf tapeworm infection and rat tapeworm infection. Hymenolepiasis is prevalent throughout the world with human infections with h.
The species name nana is derived from its small size which means dwarf of the adult worm. It is small and measures up to 2540 mm in length by one mm in diameter. During the course of a survey on the intestinal protozoan infections among 362 children in st. Himenolepiasis parasitologia medica, 4e accessmedicina. In the southeastern usa, as many as 1% of young schoolchildren. Jcm free fulltext production and use of hymenolepis.
Hymenolepis nana has a worldwide distribution with estimates of 5075 million carriers. Hymenolepis diminuta infection in a child living in the urban area of rome, italy. Human infection is usually asymptomatic, it but can cause mild gastrointestinal symptoms. The dwarf tapeworm, hymenolepis nana, cancer cells linked to. Nov 05, 2015 the morphologic features and invasive behavior of the cells were characteristic of cancer, but their small size suggested a nonhuman origin. In 1906, stiles identified an identical parasite with a rodent host and named it hymenolepis fraterna. Hymenolepiasis is the term when a human is infected with either h.
The dwarf tapeworm, hymenolepis nana, cancer cells linked. Hymenolepis nana pathogen intestinal cestode organism. Cdc hymenolepis resources for health professionals. Later, morphological characteristics were used for taxonomy identification and h. Invasion of human tissue by abnormal, proliferating, genetically. Pdf malignant transformation of hymenolepis nana in a human. Courtesy peter olson, natural history museum, london hide. Diplacanthus manus, hymenolepis nana, hymenolepis murina. Hymenolepis diminuta rodolphi, 1819 infection in a child from iran. Larval and adult beetles but optional larval stage, cysticercoid, can develop.
What is hymenolepis nana infection the dwarf tapeworm or hymenolepis nana is found worldwide. Hymenolepiasis is more frequent among children, and most human infections remain asymptomatic and selflimited. Humans and other animals become infected when they intentionally or unintentionally eat. Malignant transformation of hymenolepis nana in a human host article pdf available in new england journal of medicine 37319. Tsuchiya, three cases of infection with hymenolepis nana were incidentally encountered. Its larvae migrate only within the gut wall, and its life span is relatively short 4 to 6 wk. Pdf malignant transformation of hymenolepis nana in a. Infection is most common in children, in persons living in institutional settings, and in people who live in areas where sanitation and personal hygiene is inadequate. N engl j med 2015 nov 4 malignant transformation of h. The immune response to hymenolepis nana in mice decreases. Hymenolepis nana dwarf tapeworm infection infectious. Parasitic dna was sequenced to identify the tapeworm species.
It is the only cestode that does not require an intermediate host to develop into its infective stage. Although the cells were unrecognizable as tapeworm tissue, immunohistochemical staining and probe hybridization. Hymenolepis nana, the dwarf tapeworm, is the smallest tapeworm to infect humans. Hymenolepis nana infestation is commonly diagnosed in.
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