Establishment of hymenolepis diminuta life cycle to provide. May also exhibit dizziness, irritability, sleep disturbance, and seizures. As parasite burden increases symptoms become more likely. It requires only one host but can also cycle through two. Ova from faeces of other infected humans or rats pollute water or food which is swallowed by new human host.
Humans, rodents most common tapeworm of humans in the world 1% rate of infection in the southern u. Characteristics and life cycle hymenolepis diminuta is a small parasitic worm tapeworm commonly found in rats and mice. 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. Its larvae migrate only within the gut wall, and its life span is relatively short 4 to 6 weeks.
Presents with crampy abdominal pain, diarrhea, anorexia, and anal pruritus. Such autoinfection can persist for years and lead to a. It is interesting to note that the cysticercoid larval stage can develop in these hosts when this happens. In this article we will discuss about hymenolepis nana. 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, especially children.
E ggs of the tapeworm hymenolepis nana are infective when passed with the stool, but cannot survive more than about 10 days outside the body when eggs are ingested by an arthropod intermediate host a variety of fleas and beetles can serve as intermediate hosts, they develop into cysticercoids, which can infect humans or rodents upon ingestion and develop into adults in the small intestine. Hymenolepis nana, hymenolepis diminuta, dipylidium caninum2 duration. Transmission of hymenolepiasis stanford university. As mentioned above, hymenolepis nana does not require an intermediate host to complete its life cycle. Establishment of hymenolepis diminuta life cycle to. Hymenolepis diminuta infection infectious diseases msd. Their distribution is worldwide, they have been reported in temperate to tropical environments, and particularly in places with poor sanitation. The life cycle is completed in a single host, man and does not require any intermediate host. The filaments arise from knoblike projections at opposite poles of this layer.
One reason for facultative nature of the lifecycle is that h. Laboratory diagnostic of hymenolepis nana dwarf tapeworm. Eggs hatch in the duodenum, releasing oncospheres, which penetrate the mucosa and come to lie in lymph channels of the villi. Hymenolepis diminuta is a cestode of rodents infrequently seen in humans and frequently found in rodents. Hymenolepis nana, a tiny intestinal tapeworm, is one of the most common human cestodes. The dwarf tapeworm, hymenolepis nana, cancer cells linked to. Department of parasitology, faculty of pharmacy, university of valencia, valencia, spain.
Human infection is usually asymptomatic, it but can cause mild gastrointestinal symptoms. Available formats pdf please select a format to send. Hymenolepiasis is caused by two cestodes tapeworm species, hymenolepis nana the dwarf tapeworm, adults measuring 15 to 40 mm in length and hymenolepis dimnuta rat tapeworm, adults measuring 20 to 60 cm in length. The dwarf tapeworm is among the few intestinal worms that can have a reproductive life cycle without requiring an intermediate host 19. This cestode belongs to a large family known as hymenolepididae. 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. Apr 20, 2015 hymenolepiasis is the most common intestinal tapeworm infection of humans caused by worm of family cestoda, genus hymenolepis and species nana.
In 1906, stiles identified an identical parasite with a rodent host and named it hymenolepis fraterna. 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. Hymenolepis nana definition of hymenolepis nana by medical. However, this parasite may be present in a number of other animal transport hosts, such as fleas, beetles, rats and house mice. This infection does not require an intermediate host and infection can occur directly from one. Start studying cestodes hymenolepis diminuta and hymenolepis nana. Hymenolepiasis is primarily caused by the cestode tapeworm species, hymenolepis nana the dwarf tapeworm, adults measuring 15 to 40 mm in length. Hosts accidentally ingest arthropods rice and flour beetles infected with cysticercoid larva.
Eggs of hymenolepis nana are immediately infective when passed with the stool and cannot survive more than 10 days in the external environment. Hymenolepiasis is the most common intestinal tapeworm infection of humans caused by worm of family cestoda, genus hymenolepis and species nana. When fully embryonated eggs in human faeces are ingested by man, only one host, they hatch in the intestine, then the free oncospheres penetrate into the villi of the small intestine and metamorphose into young cercocysts or cysticercoids larvae, fig. The fact that an intermediate host is not required in the life cycle was determined in the late 1800s. Hymenolepis nana, the dwarf tapeworm, is the smallest and a common tapeworm in humans worldwide. Hymenolepis nana is the most common tapeworm in humans. If larvabearing eggs enter the human gastrointestinal tract, the oncospheres are released into the duodenum and attatch to. Hymenolepis nana dwarf tapeworm infection infectious. 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. Cestodes hymenolepis diminuta and hymenolepis nana. Hymenolepis nana life cycle information by catalina maya. Larval and adult beetles but optional larval stage, cysticercoid, can develop in d.
He recovered a countless number of them at a postmortem on a boy who had. Causal agent, life cycle, and geographic distribution. Hymenolepis nana can complete its life cycle through either direct or indirect means 1,103. Biologia simplificada com emerson inacio 4,735 views. Life cycles for all the genera listed in which primates serve as definitive host, except one, are indirect and require an arthropod intermediate host for completion of the cycle. Hymenolepis nana, the dwarf tapeworm, is the smallest tapeworm to infect humans. Dwarf tapeworm is a cosmopolitan species though most common in temperate zones, and is. View enhanced pdf access article on wiley online library html view. Man and rat act as both definitive and intermediate hosts. 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. Eggs of hymenolepis nana are immediately infective when passed with the stool and cannot survive more than 10 days in the. This infection does not require an intermediate host and infection can occur directly from one infected person to another by fecaloral transmission. Man acquires infections by injection of fully embroynated egg. The dwarf tapeworm was found in man for the first time by bilharz, in cairo, egypt, in 1851.
Nov 24, 2018 as mentioned above, hymenolepis nana does not require an intermediate host to complete its life cycle. Hymenolepis cantaniana is a type of tapeworm that is an internal parasite of chickens. Later, morphological characteristics were used for taxonomy identification and h. The main object of this experimental work was to practise laboratory production both adult and the larval stage of hymenolepis diminuta with conventional modification to make further studies easier. Learn vocabulary, terms, and more with flashcards, games, and other study tools. It is small and measures up to 2540 mm in length by one mm in diameter. It is possible for the worms entire life cycle to be completed in the bowel, so infection can. It is also known as the dwarf tapeworm due to its particularly small size adults are only 1540 mm long. Hymenolepis nana is the smallest of all tapeworms found in humans and is appropriately described as the dwarf tapeworm. Pdf heavy hymenolepis nana infection possibly through organic.
The hymenolepis nana life cycle is illustrated and explained on this page. Malignant transformation of hymenolepis nana in a human host. Hymenolepis nana has been called the dwarf tapeworm and has a worldwide distribution. The images i made them from scratch, i got some diagrams from books and from an image on the internet, also the information about the cycle comes from these books.
Description of hymenolepis microstoma nottingham strain. Humans and other animals become infected when they intentionally or unintentionally eat material contaminated by insects. The onehost account of the life cycle of hymenolepis fraterna promulgated by grassi and rovelli and joyeux is thus the correct one, though this does not exclude the possibility of the hymenolepis egg occasionally developing into a cysticercoid inside the bodycavity of a flea and undergoing the rest of its development when the flea is eaten by. 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. View enhanced pdf access article on wiley online library html view download pdf for offline viewing. It is the only cestode that does not require an intermediate host to develop into its infective stage. The dwarf tapeworms mature into a life form referred to as a cysticercoid in the insect. Heavy hymenolepis nana infection possibly through organic. Hymenolepis nana life cycle online biology dictionary.
Hymenolepis is generally found in the feces of rats which is consumed by its secondary hosts. The infection is most commonly seen in children, although. Larval and adult beetles but optional larval stage, cysticercoid, can develop. Diplacanthus manus, hymenolepis nana, hymenolepis murina. It is inside the body cavity of these intermediate hosts that the ingested egg by way of contaminated feces hatches and. Some common intermediate hosts include flour moths, flour beetles, meal worms, and cockroaches.
39 121 1393 1499 377 1385 1094 267 541 1082 68 1390 712 456 1505 501 69 1228 138 916 1574 701 931 707 870 1012 1337 1225