2Class: Cestoda (Tape worm) 1- The length of the different species varies from 3mm to 10 meters.2- Segmented body: The body of the typical cestode consists of 3 distinct regions: scolex, neck, and strobila3- Scolex (head) provided with suckers, sometime hooks.4- Hermaphroditic mature segment has male and female reproductive system5- Despite the lack of a digestive system (no mouth, no gut, no anus) they do absorb food from the hosts intestine
4General MorphologyThe body of the typical cestode consists of 3 distinct regions:scolexneckstrobila
5Form and Function: The Scolex cont. The scolices of tapeworms are typically categorized as either acetabulate or bothriate, depending on the type of sucker presentAn acetabulate scolex is characterized by the presence of 4 muscular cups sunk into the equatorial surface of the scolex; cups are radially arranged equidistant from each otherIn addition to muscular cups, there may be accessory holdfast structures, such as hooks to help anchor the scolex to the host’s intestinal wallIn this case, the scolex is called an armed scolexThese hooks are usually grouped at the apical end of the scolex on a protrusible rostellumrostellum
6Scolex:is located at the anterior end and functions as an attachment structure4 suckershooklets: These hooks are usually grouped at the apical end of the scolex on a protrusible rostellum
7NeckThe neck is an unsegmented, poorly differentiated region immediately posterior to the scolexshort measuring 5 to 10 mm in length
8The StrobilaAs new proglottids are formed from the neck region, they push the older ones progressively posteriad, creating a chain of proglottids - the strobilaThe asexual process of forming segments is termed strobilation.The stroblia can be loosely subdivided into 3 regions:ImmatureMatureGravid proglottids
10gravid proglottid has a median uterus filled with eggs (50 – 80 000)
11Larval (metacestoda): 1- The larval are extracellular parasites, visible to the naked eye, seen as bladders with an scolex. 2- The external surface is a tegumentary tissue, similar to that found in the adult worm. 3- In human infection, these larvae can survive for a many years. 4- Dead parasite tissue, leaving a calcified in both muscle and brain tissue.
15Taenia solium Common name: The Pork Tapeworm. Habitat: Small intestine.Route of infection: Eating of unwell cooked Pork meat.Definitive host : Human.Intermediate host: Pork, Human (occasional).Infective stage: Cysticercus larvae (Pork).Diagnostic stage: Eggs or gravid in Feces.Disease: Adults cause: Taeniasis.Larvae cause: Cysticercosis( presences of Cysticercus larvae in brain and muscles.
16Taenia solium Adult worm 1- 2-4 meters in length) 2- Head or scolex globular in shaped with 4 suckersrounded rostellum armed withdouble rows of large and small hooksnumbering 22 to 36.3- Neckshort measuring 5 to 10 mm in length.
17Proglottids Numbers : 700 to 1000 proglottids Composed of: 1- Immature proglottid2- Mature proglottid: nearly square containing full set of functioning male and female reproductive organs3- Gravid proglottidlonger than broader consists:gravid uterus with 3 to 13 lateral uterine branches arranged.
23EPIDEMIOLOGY T. solium infection Human infected (raw or undercooked pork)Man is the only definitive host and the pigappears to be the only intermediate hostMan become the intermediate host Can be caused by:ingestion of eggs from contaminated food or waterby internal autoinfection when the eggs are carried by reverse peristalsis back to the duodenum or stomach
24Pathology 1- By adult in lumen of the small intestines : intestinal obstructionabdominal painVomiting .nauseaweight loss and diarrhea.
252- By larval stage (cysticercus) Symptoms depend on location and number of larva, which encyst in the muscle and other tissues :a. cellular reactionsb. fibrosisc. necrosiscysticercosis in the brain may cause:a. epilepsyb. meningitis, and encephalitisEye – cause blindness
27Diagnosis: 1-Adult worms: Taenia infections are diagnosis by finding gravid segments in the feces, because their eggs are identical.2- Cysticercosis:A- Serologic tests ELISA.B- X-rays may reveal calcified cysticerci.C- CT scan can show living cysticerci.
29Taenia saginata Common name: The Beef Tapeworm. Habitat: Small intestine.infection: Eating of unwell cooked cow meat.Definitive host : Human.Intermediate host: Cows also other herbivores.Infective stage: Cysticercus larvae.Diagnostic stage: Eggs and gravid in Feces.Disease: Adults cause Taeniasis.
30Taenia solium Taenia saginata Intermediate host: Pig cattle Length : m mNo. proglottids:Scolex : suckers suckers butwith hooklets no hooklets
35Echinococcus granulosus Dog tape worm Habitat: adult: Small intestine in DogsLarvae (Hydatid cyst): in Liver, Lung, brain inIntermediate hostDefinitive host : Dogs and other canines.Intermediate host: Sheep, cattle, etc, and other herbivores. Accidentally Human.Disease: Unilocular Hydatid disease.
36Morphology:3-8 mm in length.Scolex with Four suckers.Neck.Immature segment.Mature segment.Gravid segment.
37Ova: Shape Round to Oval Embryonated ( Hexacanth embryo inside) Radially striated egg shell.Onchosphere: six-hooked embryo inside the egg.
40Hydatid Cyst: At maturity, the cyst wall contains 2 layers: 1- laminated, noncellular outer tegument called the ectocyst,2- inner, germinal epithelium that produces the protoscolices called the endocystBrood capsules attached to the germinal epithelium by the stalk, extend into the fluid filled cavity of the cystEach brood capsule contains protoscolicesIf a cyst ruptures within a host, each liberated protoscolex can produce a daughter cystProtoscolices(hydatid sand)From hydatid cyst
42Types of Hydatid Cyst1-Sterile cyst2- Fertile cyst
431. Growing hydatid cyst lodged in the vital organs like Pathology:Some people may have cysts in their bodies 5-20 years without experiencing symptoms, or may never experience symptoms.A. Mechanical1. Growing hydatid cyst lodged in the vital organs likeliver, lungs, brain, heart interferes with the functions of the organs2. Infection may become fatal due to growing cyst which can cause obstruction to the organB. ToxicRupture of the cyst may produce allergic.
44A figure showing a surgery procedure to remove hydatid cyst from a human patient A hydatid cyst in the cranium of a child (the ruler at the top measures 6 inches long, and the child's brain is below the hydatid cyst). This infection resulted in the child's death.
45Diagnosis:The diagnosis of Hydatidosis relies mainly on finding cysts by:CT scan,X- RaySerological tests.
46Treatment:Surgery is the most common form of treatment for Hydatid cysts. After surgery, medication may be necessary to keep the cyst from recurring.The drug of choice isAlbendazole, mebendazol
47Prevention and Control 1- Personal hygiene2- Prevent dogs from eating carcasses of sheep, goat cattle,etc.3- c0ntrol of stray dogs.
49Hymenolepis nana Common name: The Dwarf-Tape-Worm, ---Nanos = dwarf Disease: Hymenolepiasis.Habitat: Small intestineDefinitive host: Human, Mice,RatsInfective stage:1- Eggs ( if it eaten directly by Definitive host).2-Cysticercoid larvae from insects.Diagnostic stage: Eggs in feces.Hymenolepis nana
50Hosts: Definitive host Intermediate host (Optional): Fleas, Beetles HumanMiceRatsIntermediate host (Optional):Fleas, BeetlesThe only cestode that parasitizes humans without requiring an intermediate host.
51Morphology: Adult worm 1-4.5 cm long and 0.5-1 mm wide Neck is long and slenderThey have segments that are wider then they are longScolex also has four suckers and, rostellum armed with a single circle of hooksproglottids are much broader than longMale system has 3 spherical testes, and femalebi-lobed ovary
53Egg:Eggs generally measure between 30 to 47 microns in diameter.They are round to oval, and should contain a six-hooked oncosphere.They have polar filaments that lie between the eggshell and the oncosphere.polar filaments
56Pathology and Clinical disease: Most cases are asymptomatic, but with heavy infection they may be:1- abdominal pain, nausea, vomiting, diarrhea, and anemia.2- nervous symptoms, including dizziness and irritability, can occur in children.Diagnosis:Ova found in the fecespolar filaments