Family Hymenolepididae Larval stage found in intermediate host (invertebrate, arthropod) Hymenolepis diminuta, Vampirolepis (Hymenolepis) nana
Family Hymenolepididae Hymenolepids have three testes and a single ovary H. nana has a single circle of hooks on its scolex, whereas H. diminuta has no hooks
Family Hymenolepididae The family Hymenolepididae contains many species that occur in birds and two mammalian parasites (man, rodents)
Family Hymenolepididae H. diminuta is a parasite in the small intestine principally of rodents but occasionally also of dogs and even man (Ehrenford, 1977) Vampirolepis (Hymenolepis) nana is also a parasite of rodents and man
H. diminuta
H. diminuta Vitellaria Ovary Unilateral genital pore Testes
Single row of hooks Unilateral genital pore Hymenolepis nana
Both definitive host and interme
Family Taeniidae Normally the large tapeworms (except Echinococcus spp.) The gravid segments are longer than they are wide
Family Taeniidae The rostellum is usually armed with a double row of large and small hooks which have a characteristic shape The ginital pores are single and irregularly alternating
Family Taeniidae There are, as a rule, a large number of testes The ovary is situated in the posterior part of the proglottid
Family Taeniidae The uterus has a median longitudinal stem and lateral branches The eggs in gravid segments are typical of the family (radial striation)
Family Taeniidae The egg is usually seen in the faeces without its outer shell (capsule) Two envelopes separated by septa, so that the egg- envelope looks thick and radially striated
Family Taeniidae Differentiation of genera and species is based on Number and sizes of rostellar hooks Morphology of mature segments Number of uterus branches
Unarmed human tapeworm (beef tapeworm)
Proglotid of T. solium
Family Taeniidae Adult tapeworms measure from ten to hundreds of centimeters in length, depending on the species
Family Taeniidae The scolex has four suckers and a nonretractable rostellum armed with two rows of hooks (except for T. saginata)
Family Taeniidae The segments are more or less rectangular Unilateral genital pores alternating irregularly from one side to the other along the strobila
Family Taeniidae Gravid taeniid segments are shed and exit from the carnivorous definitive host by way of the anus
Family Taeniidae The segments crawl about on the surface of the fecal mass, emptying themselves of their eggs (oncospheres) in the process
Family Taeniidae If ingested by a suitable vertebrate intermediate host, the egg hatches and hexacanth embryo enters the wall of the intestine and migrates to its organ of predilection
Family Taeniidae Usually the liver and peritoneal membranes or the skeletal and cardiac muscles
Family Taeniidae Here the hexacanth embryo grows, cavitates, and differentiates to form the second-stage larva, which is infective to the definitive host
Family Taeniidae The fully developed second-stage larva of the family Taeniidae consists of a fluid-filled bladder with one or more scolices often called a bladderworm
Family Taeniidae When a second-stage larva is ingested by a suitable definitive host, the bladder is digested away, the scolex embeds itself in the mucosa of the small intestine
Family Taeniidae Eggs of taeniid tapeworms first appear in the feces in six to nine weeks after ingestion of the larva
Family Taeniidae The larval stage found in intermediate host (vertebrate) is a cysticercus, a coenurus or an echinococcus (hydatid) cyst
Family Taeniidae Taenia solium (Pork tapeworm) T. saginata (Beef tapeworm) T. taeniaeformis (Hydatigena taeniaformis) (Cat and Dog tapeworm) T. hydatigena (Dog tapeworm) T. pisiformis (Cat tapeworm) T. multiceps (Multiceps serialis) (Dog tapeworm) T. ovis (Dog tapeworm) Echinococcus granulosus (Dog tapeworm) E. multilocularis (Dog tapeworm)
Basic kinds of tapeworm’s cysts There are five basic kinds of second-stage larvae (cysts). Cysticercoid Cysticercus Strobilocercus Coenurus Hydatid
Basic kinds of tapeworm’s cysts A cysticercoid is a form of larval tapeworm resembling cysticercus, but having the cyst small, almost devoid of fluid, and provided with a caudal appendage, as in Hyminolepis
Basic kinds of tapeworm’s cysts A cysticercus is a larval form of tapeworm, consisting of a single scolex enclosed in a bladder-like cyst A strobilocercus is a cysticercus that has already begun to elongate and segment while still in the intermediate host
Basic kinds of tapeworm’s cysts A coenurus consists of a single bladder with many scolices, each with the potential of developing into a mature tapeworm
Basic kinds of tapeworm’s cysts A hydatid cyst is a larval cyst stage of the tapeworms Echinococcus granulosus and E. multilocularis, which contains daughter cysts, each of which contains many scolices
Family Taeniidae There are two kinds of hydatid cysts Unilocular hydatid cysts Alveolar hydatid cysts (Multilocular cysts)
Cysticercosis Cysticercosis is an infection with cysticerci In various animals it occurs as cysts found in striated muscles and causes no adverse symptoms (called also beef measles, pork measles, and sheep measles)
Cysticercosis The cysticercus of the canine taeniid tapeworm Taenia hydatigena migrates through the liver tissue and encysts on the the peritoneal membranes of cattle, sheep, swine, and certain wild ungulates
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