【正文】 ation of eggs and proglottids in feces is diagnostic for taeniasis. ? Repeated examination and concentration techniques will increase the likelihood of detecting light infections. ? Species determination of Taenia is impossible if solely based on microscopic examination of eggs, because all Taenia species produce eggs that are morphologically identical. ? Eggs of Taenia sp. are also indistinguishable from those produced by cestodes of the genus Echinococcus. ? Microscopic identification of gravid proglottids (or, more rarely, examination of the scolex) allows species determination. ? TAKE EXTREME CARE IN PROCESSING THE SAMPLES! ? INGESTION OF EGGS CAN RESULT IN CYSTICERCOSIS! ? The prognosis for intestinal taeniasis is good, but the infection should be terminated to reduce the risk of cysticercosis! Diagnostic findings ? Microscopy: ? 1 egg ? * The eggs can not be used as species identification. 2 scolex Differential Morphology of the Diagnostic stages of the two species: gravid segment Species (Gravid segment) Size Appearance of Uterus Other Taenia solium 12 mm in length x 57 mm wide Central stem with 713 main lateral branches on each side. Usually on surface of fecal material. May be in short chains of 23 proglottids. Taenia saginata 1620 mm long 57 mm wide. Central stem with 1530 main lateral branches on each side. Usually on surface of fecal material. May be single detached proglottids 3 gravid segment The most important diagnostic stage of the two species taeniasis. TAENIA SOLIUM ? Endemic in less developed countries where pigs are raised as food source. Latin America, most of Asia, subsaharan Africa, and parts of Oceania. ? Infection with the adult forms of the parasite produces similar symptoms to infection with T. saginata. The Lancet (2022) 361: 547 Cysticerci: (A) as seen in infected pork。m, with a thick radially striated brown shell. Inside each shell is an embryonated oncosphere with 6 hooks. CDC Developmental stages (metacestodes) ? Pseudophyllidean cestodes ? procercoid: in the 1st ? Intermediate host.(at an end there is a cerere=tail with 6 hooklets) ? plerocercoid :The larvae look fairly similar to the adult In the second host ? Cyclophyllidean ? The medically important larvae are ? cysticercoid, ? cysticercus ? and hydatid ? (some of these larvae provided amplification ? （Coenurus=many scolices) (D. latum) (D. latum) (T. solium) (E. granulosus) (Hymenolepis sp.) Differentiation of the two orders (tapeworms) Pseudophyllidea Cyclophyllidea Scolex amp。 holdfast 2 sucking grooves 4 suckers Uterus curved ducts sacklike, without with opening opening Vitelline gland folliclelike, anterior masses, to ovary posterior to ovary Intermediate host 2 1 Egg elliptic, thin shell, spherical, thick an operculum, an egg embryophore, cell and many yolk cells an oncosphere Morphology of adult tapeworm Adult consists of segments (proglottids) 1 Scolex (head) 2 Neck (the region of segment proliferation) 3 Strobila ( A chain of segments behind the neck) Immature segments Mature segments Gravid segments Scolex/neck/ immature proglotid Anterior region of showing the scolex and neck region. The proglottids on the right are immature。m a thick embryophore an oncosphere inside an egg shell outside (usually break away from the eggs in the feces) Gravid segment ( the primary lateral branches of the uterus) Taenia solium Taenia saginata The uterus The uterus has 7 to 13 has 15 to 30 lateral branches lateral branches on each side on each side Life cycle of Taenia solium Humans serve as final hosts as well as intermediate hosts in the life cycle of Taenia solium. ( both adult and bladder worm parasite in humans) 1 The adult worm lives in the small intestine of humans( pork tapeworm infection) 2 The larvae (Cysticercus cellulosea, bladder worm ) localize and develop in pigs (intermediate host) 3 The cysticercus cellulosae may also infect humans causing cystcercosis (humans as intermediate hosts) Life cycle of Taenia saginata The life cycle of Taenia saginata is similar to that of Taenia solium, but the intermediate host is cattle. The custicercus bovis (the beef bladder worm ) nearly does not parasite in human body. Humans serve as the final hosts only. (beef worm infection) Life cycle of Taenia saginata and Taenia solium ? Humans are the only definitive hosts for Taenia saginata and Taenia solium. ? Eggs or gravid proglottids are passed with feces ? The eggs can survive for days to months in the ? environment. ? Cattle (T. saginata) and pigs (T. solium) bee infected by ingesting eggs or gravid proglottids ? In the animal39。 an ovar