Cyclophyllidean Tapeworms

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Cyclophyllidean Tapeworms

  1. 1. Order Cyclophyllidea - Chapter 21 Major order of tapeworms of medical and veterinary importance General Characteristics of the Order: 1. Scolex has __________________ and a _________________________ + hooks 2. Common genital pore is lateral 3. Single compact ________________________________ beneath ovary
  2. 2. Order Cyclophyllidea 4. Gravid proglottids are _______________________________; proglottid ruptures on land to disseminate eggs 5. Life cycle involves 2 hosts - intermediate host and definitive host Tapeworms of medical and veterinary importance are found in 3 families. The first family is the Family Taeniidae.
  3. 3. Taenia saginata = Taeniarhynchus saginatus Beef tapeworm of humans - humans are the only definitive host and cattle are the only intermediate host DISTRIBUTION -
  4. 4. Taenia saginata ADULT MORPHOLOGY: Scolex has 4 acetabula but lacks ___________________________________ Strobila commonly reaches lengths of 10 to 15 feet (record is 75 ft.) and may contain up to 2000 proglottids.
  5. 5. Taenia saginata ADULT MORPHOLOGY: Mature proglottids contain male and female organs Testes Vas deferens Genital pore Vagina uterus Ovary Vitellarium
  6. 6. Taenia saginata ADULT MORPHOLOGY: Gravid proglottids are identified by presence of ____________________________ - diagnostic stage in human feces
  7. 7. Life Cycle of Taenia saginata 1. Adult tapeworm occurs in human ______________________ 2. Gravid proglottid is shed in feces - may actively crawl about in feces. 3. Gravid proglottid ruptures on land during drying and releases eggs onto soil.
  8. 8. Life Cycle of Taenia saginata 4. Grazing cow (intermediate host) ingests eggs. 5. Oncosphere hatches from egg in cow small intestine, penetrates intestine, and enters circulation.
  9. 9. . 6. Oncosphere reaches skeletal muscle and becomes a _____________________ (scolex surrounded by bladder)   - beef infected with cysticerci is commonly called _____________________ Life Cycle of Taenia saginata
  10. 10. Life Cycle of Taenia saginata 7. Human eats raw or poorly cooked beef containing cysticerci. Scolex evaginates, attaches to wall of ileum, and begins strobilization. Adult reaches maturity in 2-12 weeks.  
  11. 12. Life Cycle Stages of Taenia saginata Cysticercus with invaginated scolex Cysticercus with evaginated scolex Egg has a striated embryophore and inner oncosphere with 6 hooks Scolex Mature proglottid Gravid proglottid (diagnostic in feces!)
  12. 13. Human Infections EPIDEMIOLOGY - human infections associated with ________________________________________________________________________________________________ PATHOLOGY: 1. 2. Parasite is never life-threatening.  
  13. 14. DIAGNOSIS - identify gravid proglottid in feces with 15-20 lateral uterine arms. Eggs are not diagnostic as they are typically not found in feces. Eggs cannot be distinquished from other taeniid tapeworms.
  14. 15. TREATMENT - ___________________________________ are effective   PREVENTION - __________________________________ _________________________________________________ Cysticerci in beef are large and are found during inspection of beef in packing plant. If found, carcass is condemned.
  15. 16. Human Infections   These were used as diet pills from 1900 to 1920. Reappeared again in the 1970’s as a weight loss method. Recently sold again as “Megaslim” and “Weight-B-Gone” The Tapeworm Miracle Diet Pills are Back Posted on December 1, 2005 by Sam Markens The IndoMed company of southern San Francisco has produced a new product which has for some reason slipped past the FDA. Their new weight loss pill called Weight-B-Gone has some interesting side effects. This once a week pill, when ingested, will cause the patient to lose as much weight as they want on a steady basis while allowing them to eat whatever they want and as much as they like. The “catch” is that these pills contain a genetically engineered head of a Taenia saginata , otherwise known as the Beef Tapeworm.
  16. 17.       Megaslim: the cheap alternative to diet and exercise. Michael Swaim Staff Writer An FDA probe into Megaslim, the new “ miracle diet medication, ” revealed that the pills, which are sold out of a Wisconsin warehouse, are in fact nothing more than infant tapeworms. Randall Corman, CEO of Fly By Night Inc., the company which manufactures the pills, has been under legal investigation since several of his patients complained of “ cramping, gas, and tapeworms. ” Corman defended the legitimacy of these pills, saying, “ the vast majority of my clients have been overjoyed with their results. ” Corman has also set up a “ testimonials ” page on his website, where former patients can write in to voice their opinions of his new drug. Mary Shechter of Minnesota had this to say: “ Megaslim has changed my life. Now, I eat pizza and donuts for three meals a day, and I still lose weight! When friends ask me what my secret is, I have to giggle, just thinking of that cute little tapeworm, feasting away on my intestinal wall. ” Corman suspended the infant tapeworms in gelatin and began selling them as diet pills earlier this year. His advertisement, which ran in a local newspaper, promised “ fast, noticeable results ” and “ only minor parasitic infestation. ” It is with this that the FDA has taken issue. According to Jeremy Franklin, head of the FDA ’ s investigation into Megaslim, a tapeworm infestation is anything but “ minor. ” “ Tapeworms are not to be taken lightly, ” he told reporters Tuesday. “ Once infected with a worm, a subject can experience diarrhea, gastral cramps, weakness, fatigue, malnutrition, and a dangerously sexy waistline. Though adorable, tapeworms should be considered a serious health risk. ” Following the FDA ’ s study, Corman and Franklin met with litigators and have since come to a settlement in the case. After agreeing to add “ may cause tapeworms ” to the list of side-effects, the FDA has officially approved Megaslim for sale and dispersal to the general public. Corman, overjoyed with the decision, says he is looking forward to “ thinner citizens, fatter worms, and ten percent of the sale revenue. ” Miracle Diet Pills Really Just Tapeworm Eggs
  17. 18. Taenia solium Pork tapeworm of humans - humans are the only definitive host and pigs are the intermediate host This parasite is much more dangerous than the beef tapeworm, as humans can also serve as ___________________________________ _______________________________________________________   DISTRIBUTION - _______________________________________________________ Common in Slavic countries of Europe and Central & South America Infections in U.S. commonly associated with migrant workers from Central and South America
  18. 19. Taenia solium ADULT MORPHOLOGY: Scolex with 4 acetabula and rostellum with 2 circles of hooks. Strobila commonly reaches lengths of 6-10 feet and contain up to 1000 proglottids.
  19. 20. Taenia solium ADULT MORPHOLOGY: Mature proglottids are similar to T. saginatus. Gravid proglottids contain _________________________________________ - diagnostic stage in human feces.
  20. 21. Life Cycle Stages of Taenia solium Cysticercus with invaginated scolex Egg has a striated embryophore and inner oncosphere with 6 hooks Scolex Mature proglottid Gravid proglottid (diagnostic in feces!)
  21. 22. Life Cycle of Taenia solium Life cycle is similar to the beef tapeworm: 1. Adult tapeworm occurs in _____________ _____________________ 2. Gravid proglottid is shed in feces. 3. Gravid proglottid ruptures on land, releasing eggs onto soil.
  22. 23. Life Cycle of Taenia solium 4. Pig intermediate host ingests eggs. 5. In pig, oncosphere hatches from egg and enters circulation. 6. Oncosphere reaches skeletal muscle and becomes a ____________________ - pork infected with cysticerci is ____________________
  23. 24. Life Cycle of Taenia solium 7. Human eats raw or poorly cooked pork containing cysticerci. Adult tapeworm develops in small intestine.
  24. 25. Life Cycle of Taenia solium Cysticercus with invaginated scolex Cysticercus with evaginated scolex Measly pork
  25. 26. Life Cycle of Taenia solium - Cysticercosis Humans can also serve as accidental intermediate hosts of the cysticerci - disease is called ____________________________
  26. 27. Life Cycle of Taenia solium - Cysticercosis <ul><li>Humans can also serve as accidental intermediate hosts of the cysticerci - disease is called ____________________________ </li></ul><ul><li>Methods of human infection: </li></ul><ul><li>ingest ___________________ via fecal contamination from a human infected with adult tapeworm. </li></ul><ul><ul><li>Don’t have to eat pork - recent infections of Jewish people in NY from Mexican housekeepers/cooks </li></ul></ul><ul><li>2. autoinfection - caused by________________________________ </li></ul><ul><ul><li>  human is host of adult which releases gravid proglottids </li></ul></ul><ul><ul><li>gravid proglottids rupture in stomach or duodenum releasing eggs </li></ul></ul>
  27. 28. Life Cycle of Taenia solium - Cysticercosis <ul><li>1. When eggs enter small intestine, _______________________ hatch, penetrate intestine, and enter circulation. </li></ul><ul><li>2. Oncospheres are carried to many organ where they become _______________________ </li></ul><ul><li>Cysticerci commonly occur in 2 regions: </li></ul><ul><li>_______________________ _________________________ (little pathology) </li></ul><ul><li>________________________ - results in disorder called neurocysticercosis </li></ul>
  28. 29. Pathology of Taenia solium <ul><li>Adults - symptoms similar to T. saginatus - _________________________________________________ </li></ul><ul><li>Neurocysticercosis - very dangerous and potentially fatal! </li></ul><ul><ul><li>  When cysticerci die in the brain, they elicit a severe inflammatory reaction and destroy brain tissue. </li></ul></ul><ul><ul><li>  ______________________________________ occur  </li></ul></ul><ul><ul><li>Death? ______________________________________ </li></ul></ul><ul><li>  </li></ul>
  29. 30. Neurocysticercosis - fatal cases
  30. 32. DIAGNOSIS - adults are identified by finding gravid proglottid with ________________________________ in human feces. Cysticerci are identified by X-ray, CAT scan, and MRI. TREATMENT - ______________________ is useful against adults ___________________________________ is somewhat effective against cysticerci if brain damage is not severe.
  31. 33. PREVENTION 1. ____________________________________________ (Infections in U.S. are rare as pigs do not scavenge on human fecal wastes.) 2. __________________________________________________ (this also prevents trichinosis!) 3. _________________________________________________ http://animal.discovery.com/videos/monsters-inside-me-pork-tapeworm.html
  32. 34. Finding of infected pigs raises a red flag!
  33. 35. Taenia spp. of veterinary importance Taenia pisiformis Common parasite in the small intestine of ________________ __________________________________________________ I n Wisconsin? Adults are 1-3 feet long.  Adults are asymptomatic in canid definitive host.
  34. 36. Taenia pisiformis Cysticerci occur in the liver and on mesenteries in the abdominal cavity of __________________________ cysticerci oncosphere egg Adult in fox
  35. 37. Taenia multiceps Parasite in the small intestine of _____________________________________ Intermediate host is __________________________________ Larval form that develops in sheep is a ________________________________ ( has many scoleces within one bladder)   Coenuri in sheep occur in brain and spinal cord and cause _____________________________________resulting in &quot;gid&quot; or &quot;staggers&quot;
  36. 38. Taenia taeniaformis Adult tapeworm in small intestine of ____________________ which is asymptomatic. Intermediate hosts are _________________________________ Larval form is called a ________________________________
  37. 39. Echinococcus spp. Small taeniid tapeworms that infect ______________________ as definitive hosts. Humans can serve as __________________________________ of the larval form called the hydatid cyst. ________________________________ is a very serious human disease in many parts of the world.   2 important species  
  38. 40. Echinococcus granulosus <ul><li>ADULT MORPHOLOGY - small tapeworm - 3-6 mm long </li></ul><ul><li>consists of scolex, neck, immature proglottid, mature proglottid, and gravid proglottid </li></ul><ul><li>  </li></ul>
  39. 41. Life Cycle of Echinococcus granulosus 1. Adult occurs in ______________________________________________ 2. Gravid proglottid detaches and ruptures as it passes through digestive tract. Eggs are released in the feces. 3. Eggs are released on soil and are ingested by intermediate host -______________________________________________
  40. 42. Life Cycle of Echinococcus granulosus 4. ____________________ hatches in herbivore's intestine, penetrates gut, enters circulation, and reaches liver, lungs, or brain 5. Oncosphere transforms into a ______________________________________________ 6. When herbivore is eaten by canid, _______________________develop into adult tapeworms in the canid small intestine.
  41. 43. Unilocular Hydatid Cyst of Echinococcus granulosus Unilocular hydatid cyst is a large circular structure (up to 6 inches in diameter) Composed of 2 outer layers: 1. _____________________ 2._____________________ Germinal layer gives rise by asexual means to millions of _________________________ and brood capsules which produce additional protoscolices. Cyst is filled with __________________________ containing the protoscolices  
  42. 44. Unilocular Hydatid Cyst of Echinococcus granulosus Unilocular hydatid cyst is a large circular to sausage-shaped structure (up to 6 inches in diameter)  
  43. 45. Unilocular Hydatid Cyst of Echinococcus granulosus Unilocular hydatid cyst is a large circular structure (up to 6 inches in diameter) 2 outer layers: 1. laminated layer 2. germinal layer Protoscolices Hydatid fluid  
  44. 46. Human Infections of Echinococcus granulosus <ul><li>HUMAN INFECTIONS are caused by ___________________ ___________________________________________________ </li></ul><ul><ul><li>  infected dog licks anus with eggs, then licks person's face. </li></ul></ul><ul><ul><li>  In Kenya, primitive tribe eats dog intestine lightly roasted on stick - these persons have highest incidence of hydatidosis in world . </li></ul></ul><ul><ul><li>Use of nurse dogs to lick children clean in tribes in Africa </li></ul></ul><ul><li>Once the egg is ingested, oncosphere hatches, penetrates intestine, enters circulation, and comes to rest in ________________________ </li></ul><ul><li>where it forms the ______________________ </li></ul><ul><li>  </li></ul><ul><li>  </li></ul>
  45. 47. Pathology of Echinococcus granulosus Adults in canid cause no pathology. Hydatidosis in human: 1. ___________________________________________ form around unilocular hydatid in liver, lungs, or brain. 2. ________________________________________- pressure effects cause tissue damage and failure. 3. Rupture of hydatid results in fatal __________________________________ (due to hydatid fluid) 4. Calcification of hydatid occurs after many years. 5. Hydatid cysts in bone marrow cause ________________________________. Unilocular hydatid cyst grows slowly in human. It may be many years before cyst enlarges enough to cause problems.  
  46. 48. Pathology of Echinococcus granulosus   Unilocular hydatid cyst in the lung Note pressure effects exerted by cyst that crowds and destroys lung tissue
  47. 49. Pathology of Echinococcus granulosus   6 inch unilocular hydatid cyst that killed a 7 year-old-girl in Colorado
  48. 50. Diagnosis of Echinococcus granulosus   <ul><li>DIAGNOSIS: </li></ul><ul><li>IN DOGS: identify eggs in feces. Eggs are characterized by dense striated __________________________ surrounding __________________________. </li></ul><ul><li>Eggs, however, cannot be distinquished from any other taeniid. </li></ul><ul><li>. </li></ul><ul><li>  </li></ul>embryophore oncosphere
  49. 51. Diagnosis of Echinococcus granulosus   IN HUMAN INFECTIONS: X-rays, CAT scan, and MRI will detect the hydatid cysts.  
  50. 52. Treatment of Echinococcus granulosus   TREATMENT - ______________________________________ Surgeon must be careful not to rupture cyst! Why?   Surgical removal of 3 unilocular hydatid cysts from a Kenyan woman
  51. 53. Distribution of Echinococcus granulosus <ul><li>DISTRIBUTION - associated with range of intermediate hosts: </li></ul><ul><li>______________________________________ of world </li></ul><ul><li>northern distribution associated with _______________________________  </li></ul><ul><li>In the U. S. parasite occurs in southwestern states ; in Wisconsin? </li></ul><ul><li>  </li></ul>
  52. 54. Echinococcus multilocularis This species has recently been reported in __________________ in the upper Midwest (North and South Dakota, Minnesota, Iowa, and southern Wisconsin). Recently identified in Illinois and Ohio.    
  53. 55. Echinococcus multilocularis <ul><li>Humans can serve as __________________________________ </li></ul><ul><li>___________________________________________________ </li></ul><ul><ul><li>Many human cases have been reported in Alaska. </li></ul></ul><ul><ul><li>  First human case in lower 48 states was reported in 1979 in a Minnesota woman.   </li></ul></ul>
  54. 56. Echinococcus multilocularis in Minnesota
  55. 57. Life Cycle of Echinococcus multilocularis <ul><li>1. Adult tapeworm occurs in _______________________________________________ </li></ul><ul><li>Dogs, cats, and coyotes can also serve as definitive hosts. </li></ul><ul><li>Adult is small - 1-2 mm long </li></ul>
  56. 58. 2. Eggs are released in feces and are ingested by _____________________________________________________________________ _______________________ develops in liver and body cavity of rodent. Alveolar hydatid has the ability to metastasize and infiltrate surrounding tissues like a cancer.
  57. 59. 3. Fox becomes infected by eating rodent intermediate host containing alveolar hydatid host. 4. Human becomes accidental intermediate by _______________________________________________________________
  58. 60. Life Cycle of Echinococcus multilocularis Alveolar hydatid cyst in a mouse - cyst metastasizes from the liver to fill the body cavity
  59. 61. Life Cycle of Echinococcus multilocularis Alveolar hydatid cyst in the liver. Note the laminated layer, germinal layer, protoscolices. PATHOLOGY involves _____________________________________________________ _________________________________________________________________________
  60. 62. Comparison of unilocular and alveolar hydatid cysts
  61. 63. Life Cycle of Echinococcus multilocularis DIAGNOSIS of the alveolar hydatid is difficult in human infections. It is often mistaken for a malignant liver tumor. TREATMENT involves _______________________________________ Difficult to get entire cyst and recurrences occur 20-40% of the time. Extensive liver cysts are inoperable and require _________________________________________ HUMAN INFECTIONS are rare but anyone handling ________________ (trappers, skinners) are at greatest risk for infection. 
  62. 64. Distribution of Echinococcus multilocularis The parasite has a circumpolar distribution in ________________________________________________________________________________________________________  
  63. 65. Family Hymenolepidae Large family of tapeworms in birds and mammals Characterized by proglottids that are wider then long; mature proglottids contain 3 testes.     Hymenolepis diminuta Cosmopolitan parasite in the ______________________________ Human infections are rare but have been reported in Egypt and India.
  64. 66. Adult of Hymenolepis diminuta Scolex with 4 acetabula and rostellum lacking hooks 3 testes/proglottid Strobila reaches lengths of 1 to 3 feet.
  65. 67. Life Cycle of Hymenolepis diminuta 1. Adult tapeworm in ____________________________________ 2. Gravid proglottids rupture in large intestine and eggs are released in the feces.
  66. 68. Life Cycle of Hymenolepis diminuta 3. Eggs are ingested by ______________________________________ 4. Oncosphere transforms into a ___________________ in body cavity of the beetle.   5. Grain beetle is eaten by rat. Cysticercoid develops into the adult.
  67. 69. Life Cycle Stages of Hymenolepis diminuta Cysticercoid Grain Beetle intermediate
  68. 70. Human Infections of Hymenolepis diminuta Human infections are associated with _______________________________________________________________________________________________  
  69. 71. Diagnosis of Hymenolepis diminuta Identification of eggs in the feces. Eggs are characterized by thick, translucent ______________________ surrounding _______________________with 6 hooks.  
  70. 72. Importance of Hymenolepis diminuta Hymenolepis diminuta is easily maintained in laboratory rats Subject of numerous experimental studies and EM studies    
  71. 73. Hymenolepis (=Vampirolepis) nana Known as the _____________________________________ - probably the most common tapeworm parasite of humans.   Commonly infects children. Tapeworm is cosmopolitan in distribution. Prevalence of 1% in humans in the southern U.S.  
  72. 74. Hymenolepis (=Vampirolepis) nana DEFINITIVE HOSTS - ___________________ ______________________________________ ADULT MORPHOLOGY - scolex with 4 acetabula and rostellum with circle of hooks Strobila reaches length of 40 mm (1 - 1 ¼ in.) Proglottids wider than long and contain 3 testes    
  73. 75. Life Cycle of Hymenolepis nana   1. Adult tapeworm in __________________________ 2. Egg egg released in feces. 3. Egg ingested by optional intermediate host - ___________________________ 4. _________________________ develops in insect body cavity and is infective to human or rat definitive host.
  74. 76. Life Cycle of Hymenolepis nana   <ul><li>5. Autoinfection is more common: </li></ul><ul><li>egg is ingested by the human </li></ul><ul><li>egg hatches in small intestine and becomes a ________________________ inside a _________________ ________________________ </li></ul><ul><li>6. After a week, cysticercoid emerges and becomes an adult in human small intestine. </li></ul>
  75. 77. Hymenolepis nana   Cysticercoids in villi of small intestine in autoinfection
  76. 78. Hymenolepis nana   <ul><li>PATHOLOGY - Infections of a few tapeworms are _____________________ </li></ul><ul><ul><li>In heavy infections associated with autoinfection, worms cause ______________________________________________________. Never life-threatening. </li></ul></ul><ul><li>DIAGNOSIS - ID ova in feces </li></ul><ul><ul><li>similar to H. diminuta but smaller </li></ul></ul><ul><li>TREATMENT - ______________________ </li></ul>
  77. 79. Family Dilepidae Dipylidium caninum Double-pored tapeworm of __________________. Cosmopolitan distribution. Other definitive hosts are _____________________________  
  78. 80. Adult of Dipylidium caninum Scolex with tiny hooks on rostellun Mature proglottids recognized by presence of 2 sets of reproductive organs. Genital pores occur on each side of proglottid. Gravid proglottids are cucumber-shaped and contain many egg sacs.
  79. 81. Adult of Dipylidium caninum Strobila is about 1 foot long. Gravid proglottids are easily recognized by cucumber-shape. Scolex with rostellum containing tiny hooks and 4 acetabula.
  80. 82. Adult of Dipylidium caninum Mature proglottid Testes Vas deferens Genital pore Vagina Ovary Vitellarium Testes
  81. 83. Adult of Dipylidium caninum <ul><li>Gravid proglottid - _______________________________ </li></ul><ul><li>cucumber shape (tapered at ends) with 2 genital pores </li></ul><ul><li>contains egg packets </li></ul><ul><li>motile and may crawl out of dog’s anus </li></ul>Egg packet
  82. 84. Life Cycle of Dipylidium caninum 1. Adult tapeworm in ____________________________________________ 2. Gravid proglottid (diagnostic stage) released in feces 3. Eggs in packets are released from gravid proglottid as it dries.
  83. 85. Life Cycle of Dipylidium caninum 4. Egg ingested by intermediate host - ____________________________________________   5. _____________________ develops in the body cavity of louse or flea.  6. When flea or louse is ingested by dog or human, cysticercoid becomes adult in small intestine.
  84. 86. Human Infections of Dipylidium caninum Human infections common in children associated with pets . Why? PATHOLOGY - Few worms are __________________________ Heavy infections result in _______________________________________ TREATMENT - ____________________________________

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