May 14, 2014 taenia solium completes its life cycle in two different vertebrate hosts, man and pig. Human infection is acquired by eating raw or undercooked beef or pork containing the encysted larval stage, the cysticercus. It is a flatribbon like tape worms that causes intestinal taeniasis. This egg can be found in feces, water or sewage or feed and can survive during the winter in grasslands and fresh, brackish and salty water, and even survive the treatment of sewage treatment. Little angel safety kids songs with nursery rhymes duration. At this point of maturity, the tapeworm is then able to release proglottids to restart is life cycle. The sperms received are stored in the seminal receptacle. The structure and life cycle of taenia with diagram. Taenia solium can also cause cysticercosis life cycle. Taenia solium and taenia asiatica are acquired from ingestion of undercooked pork. This lesson provides a very detailed overview of the life cycle, morphology, and cytology of taenia solium. The eggs or gravid segments are passed out with the faeces on the ground.
Pdf taenia saginata is the most common species of tapeworm infecting humans. The body is elongated, dorsoventrally flattened and ribbonlike. In the past, taenia saginata has been reported in asia, europe, africa, and north and south america. A characteristic that both tapeworms of these do share is their almost identical eggs. The cirrus of the segment is inserted into the vagina of the same segment. Taenia saginata is one of two agents responsible for human taeniasis, the other being. Life cycle definitive host man stage leaving the body gravid proglottids, occasional embryonated eggs intermediate host pigs and man infectious stage for the definitive host infectious eggs for cysticercosis, cysticerci for tapeworm infection. Ova of two species are similar, but larvae and segments with scolex are different.
Parasitology 8 a taenia saginata solium beef tapeworm pork cysticercosis cysticercus pig. The life cycle of the beef tapeworm is a bit complicated and has some essential steps to complete its cycle. Some experts postulate that if an adult tapeworm is present in the intestine, gravid proglottids tapeworm segments may be passed retrograde from the intestine to the stomach, where oncospheres immature form of the parasite enclosed. Although there are multiple species of cestodes, this paper will focus on three particular species that cause human disease. Taenia saginata beef tapeworm infection infectious. Adult worms are rarely pathogenic but the encysted larval stage cysticercus cellulosae of the worm caused a serious disease in. Adult tapeworm stages develop in the human intestine. Ingested by the definitive host young tapes young tapes attach to the intestinal lining and develop into. You can see below a clear example of the hooks present in between the four suckers.
Taeniasis refers to infection with the tapeworm form of one of three taenia species. Taenia solium and taenia saginata linkedin slideshare. Life cycle definitive hosts dogs, fox, coyote, wolf small intestine gravid proglottids passed in feces ova disseminated in environment by motile proglottid intermediate host rabbits or squirrels cysticercus larvae bladder worm in liver and mesenteries. Taeniasis is the infection of humans with the adult tapeworm of taenia saginata or taenia solium. Cannot distinguish species of taenia tapeworms based on. It is an intestinal parasite in humans causing taeniasis a type of helminthiasis and cysticercosis in cattle.
The oncosphere is then ingested by the intermediate host, the cow in this case. Taenia saginata is a large tapeworm that causes an infection called taeniasis. Greenwood, in medical microbiology eighteenth edition, 2012. Eggs are past by the host, and survive on the pasture. Cestodes taenia saginata north dakota department of health. However, humans may also act as intermediate hosts for t. The prevalence of taenia saginata is measured by the occurrence of its infection in man and cattle. The lifehistory is complicated and digenetic, being completed in two hosts. It is also called tapeworm as the shape of the body is like a tape.
Cestodes taenia solium north dakota department of health. Figure courtesy of the cdcs division of parasitic diseases. These parasites have an indirect life cycle, cycling between a definitive and an intermediate host. Y approximately 100 million new infections of taenia worms develop annually throughout the world. Taenia saginata, the beef tapeworm, is much more prevalent than the related t. The following taenia species are zoonotic, with humans serving as the definitive host, the intermediate host, or both. In this case, eggs or gravid proglottids reenter the body through the mouth and often travel to the central nervous system cns, the muscles or the eye, where they develop into cysticerci. It is commonly known as the beef tapeworm or cattle tapeworm because it uses cows as intermediate hosts. This is essential in the complicated life cycle of this tapeworm. Restate the basic concepts of parasitology define of the various terms related to basic parasitology discuss briefly the life cycle and pathogenesis of medically important parasites apply the knowledge of the life cycle to the principles of laboratory diagnosis learning outcomes. Taenia solium pork tapeworm, taenia saginata beef tapeworm, and diphyllobothrium fish tapeworm.
The primary host is man and the secondary host is pig. It measures 5 to 10 mm in breadth by 3 to 4 mm in length. Taenia solium commonly known as the pork tapeworm or the armed tapeworm. The cestodes tapeworms taenia saginata beef tapeworm and t. Two worms circulate between man and animals, so produce zoonoses. Although ova can be identified in stool, stool examination is an insensitive method for diagnosis of intestinal tapeworms.
Jan 12, 2020 taenia saginata is a topic covered in the johns hopkins abx guide to view the entire topic, please sign in or purchase a subscription official website of the johns hopkins antibiotic abx, hiv, diabetes, and psychiatry guides, powered by unbound medicine. T aenia saginata is the largest of its genus consisting between to 2000 proglottids and can also have a lifespan of 25 years in a hosts intestine. History of taenia saginata tapeworms in northern russia. Apr 25, 2019 taenia solium commonly known as the pork tapeworm or the armed tapeworm. Humans are the only definitive hosts for these three species. Taenia saginata is then able to grow, and within three months it can reach 5 meter s long. Human infection is acquired by eating raw or undercooked beef or pork containing the encysted larval stage, the. Read this article to learn learn about the structure and life cycle of taenia. Autoinfection can also occur at this point in the life cycle via fecaloral contamination.
It contains an unarmed scolex invaginated at one side. Africa, middleeast, central and south america, europe and asia t. Taeniasis is usually diagnosed by identification of ova or proglottids. Taenia solium eggs can also cause cysticercosis life cycle. Thus, anal swabs, such as the scotch tape method, as usually done for the. The most important health problem is infection by the cysticerci, cysticercosis. Cyclophyllidea, family taeniidae with a twostage life cycle. Now that you know the complicated life cycle, take a look at the medical condition and problems that the infection this parasite causes, taeniasis. Taenia solium, the pork tapeworm of man, as adult lives in the intestine of man leading an endoparasitic life. Man is considered to be the definitive host and the pig is considered as the intermediate host. Infected humans definitive host excrete the eggs or gravid proglottids in their feces, passing the parasite from the gastrointestinal tract onto nearby vegetation. It can live for about 8 months in the flesh of cattle. Cattle are the intermediate hosts, harboring the tissue cysticerci in. Taeniasis is the infection of humans with the adult tapeworm of taenia saginata, t.
Adult worms are rarely pathogenic but the encysted larval stage cysticercus cellulosae of the worm caused a serious disease in human called cysticercosis. The life cycle begins when the bovine ingests the embryonated egg. Taenia saginata synonym taeniarhynchus saginatus, commonly known as the beef tapeworm, is a zoonotic tapeworm belonging to the order cyclophyllidea and genus taenia. Taenia solium pork tapeworm infection and cysticercosis. Except the adult, various stages of its life history are passed in the body of secondary host. Beef tapeworm taenia saginata life cycle, symptoms, diagnosis and treatment pictures included. Both have a relatively simple life cycle, alternating between man and the intermediate host. Taenia saginata, called the beef tapeworm, is a common intestinal infection worldwide. Life cycle definitive hosts dogs, wild canids small intestine gravid proglottids passed in feces ova disseminated in the environment intermediate host sheep, other ruminants, swine and humans unilocular hydatid cyst in various organs ingested by the definitive host young tapes. Man is the primary or definitive host, the secondary host for t. Tapeworm taenia solium, taenia saginata, diphyllobothrium. Taeniasis is the infection of humans with the adult tapeworm of taenia saginata or taenia.
Gravid proglottids, which are full of eggs, are excreted in feces into the environment. Among them 359 were caused by taenia saginata, three by t. Ova, larva as cysticurcus and adult forms monocious are seen as life cycle stages. Pdf history of taenia saginata tapeworms in northern russia. The adult worm lives in the small intestine of man. The infection in humans, taeniasis, is not a disease that is required by law to report. Cestodes are flat, parasitic, hermaphroditic tapeworms with complex life cycles that infect animals, including humans. Beef tapeworm tapeworm infections have been reported since 1500 b. The armed scolex may cause some inflammation of the intestinal wall, and rarely may penetrate the intestine, causing peritonitis. Taenia saginata was differentiated from taenia solium infection by the late 1700s. Proglottid is smaller than t saginata and has 7 lateral branches off the central uterus. Taenia saginata and taenia solium are two important members of the cestodes infecting man.
1220 108 5 1393 12 747 1190 830 638 278 563 34 868 994 830 940 348 685 1425 492 1300 1103 1390 981 48 1506 954 1277 590 137 824 1452 297 1188 1211 1309 682 791 1418 802 514 919 1076 1081