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2014-12-15 14:56:52
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  1. Name the larval tapeworms and their diseases
    • Spirometra (human sparganosis)
    • Taenia solium (human cysticercosis)
    • Echinococcus granulosus (Hyatidosis, echinococcosis, hydatid disease)
    • Echinococcus multilocularis (Hyatidosis, echinococcosis, hydatid disease)
    • H. nana (rare)
  2. Why is the disease called human sparganosis
    disease caused by plerocercoid larvae (spargana) of Spirometra tape worm (kinda like Diphyllobothrium)
  3. Spirometra life cycle (normal)
    • Matches D. latum
    • eggs released into water become coracidium
    • procercoid found inside cyclops (crustacean)
    • plerocercoid in amphibean/fish/snake/etc
    • cat/dog is definitive host
  4. What are the methods of infection for Sparganosis?
    • 1. Drinking water contaminated w/ cyclops copepods (most common)
    • **plerocercoids in copepod
    • 2. Ingestion of undercooked fish, amphibians, reptiles, birds, pigs, snake, etc
    • **plerocercoids in muscle
    • ex- oriental tradition of eating raw snake
    • 3. poulticing wound (vag, ulcer, eye) with split flesh of vertebrate
    • **worm crawls from flesh into applied area
  5. Describe what happens after eating meat infected with Spirometra w/ symptoms
    • Spargana (plerocercoids) wander in the deep tissues, migrate to eyes (swelling, conjunctivitis, blindness), muscles, subcutaneous tissues (lumps)
    • Chills and fever
    • Can grow up to 15"
    • May be misdiagnosed as cancer
    • **NOTE- eye infection VERY common
  6. Spirometra - diagnosis, treatment, prevention, control
    • Diagnosis: detection of parasite in tissues
    • Treatment: surgical removal of larva
    • praziquantel
    • Prevention/control: proper cooking of meat
    • boil/filter water
    • don't apply animal flesh to skin
  7. T. solium - common sites
    • Virtually every organ and tissue of the body
    • subcutaneous tissue
    • eyes
    • brain
    • muscles
    • heart
    • liver
    • lungs
    • coelom
  8. T. solium - how does infection occur, what are the most common methods of infection?
    • Infection occurs when embryonated eggs pass through the stomach and hatch in the intestine
    • 1. Consuming T. solium eggs (pig shit contaminated food, salad, water)
    • 2. Autoinfection: gravid proglottid migrates into stomach (reverse peristalsis)
  9. T. solium symptoms
    • Human cysticercosis
    • Clinical disease mostly caused by presence of cysts in brain and eyes
    • Spasms and weakness are common (muscles, liver, skin, liver)
    • neurological disorders, paralysis, vomiting, headache (brain, CNS)
    • **If a cysticercus dies it causes a SEVERE inflammatory response (any location)
    • neurocysticercosis: present in brain, often fatal
    • *NOTE - most common parasitic infestation of nervous system
  10. T. solium - diagnosis, treatment, prevention/control
    • Diagnosis: observing and feeling subcutaneous nodules, confirmed with biopsy
    • X-Ray can detect calcified cysts
    • CT scan can determine brain damage
    • Treatment: surgical removal
    • Praziquantel or Albendazole
    • *NOTE - treatment must not cause vomiting! (autoinfection)
    • Prevention: thoroughly wash salad, vegetables, keep up hygiene, sanitation, boil water, etc
    • Control: sanitary disposal of feces and pork inspection
  11. Describe the difference between the three types of Echinococcus disease
    • E. granulosus: cystic (unilocular) echinococcosis
    • very few, large cysts
    • *NOTE - most common, least harmful
    • E. granulosus: osseous echinococcosis
    • Occurs worldwide, frequent in rural areas
    • E. multilocularis: alveolar echinococcosis
    • many small cysts
    • *NOTE - most pathogenic
    • causes liver cancer
    • Occurs in Northern hemisphere (Europe, Asia, and NA)
  12. Echinococcus - describe morphology
    • smallest tapeworm (2-8mm)
    • only 3  proglottids (immature, mature, gravid)
    • Scolex has rostellum w/ 2 rows of 28-50 hooks, 4 suckers
    • Carnivores (eg dogs, cats) are definitive host
  13. Echinococcus - life cycle (normal)
    • Eggs passed in feces from definitive host (dogs)
    • Ingested by humans and intermediate hosts (contamination)
    • Hatch into oncosphere in small intestine
    • Oncospheres penetrate intestinal wall (small size)
    • Carried all over body by circ system
    • become lodged in capillary beds (liver, lung, kidney, splean, heart, etc)
    • Hydatid cysts develop (containing protoscolices (AKA hydatid sand))
    • protoscolices are ingested by dog (def. host) via ingestion of meat
    • Protoscolices develop into adults in small intestine of dogs
  14. Give examples of Echinococcus intermediate hosts
    • Rabbit, sheep, cattle, squirrel, goat, camel
    • human is dead end (unless eaten....)
  15. Describe the anatomy of each type of hydatid cyst
    • *NOTE- larvae with inverted scolices develop within the cysts (protoscolices)
    • forms after hatching and migration of oncosphere
    • Up to 30cm
    • containing liters of fluid
    • 1mm thick, 3 layered cyst wall
    • pericyst: outermost layer containing CT and fibers (host origin)
    • ectocyst: thick-layered non-cellular wall
    • endocyst: inner, thin layer that produces protoscolices
    • brood capsules attach to cyst wall via pedicel 
    • each brood capsule contains numerous protoscolices
    • hydatid sand: ruptured cysts sink to the base of the capsule
    • represent 1-2% of total cysts
    • develop in marrow cavities
    • much smaller than unilocular cysts
    • *contain no fluid
    • *contain no protoscolices
    • provoke very little host rxn, but bones can be destroyed during development
    • most commonly found in liver (Alveolar liver echinococcosis)
    • cysts grow ~1mm per month, become noticeable ~20cm
    • compression of liver = jaundice
    • *typically lack protoscolices
  16. What are the most common relationships that propagate sylvatic echinococcosis? domestic echinococcosis?
    • sylvatic
    • Wolf-moose in US/Canada
    • Dingo-wallaby
    • other carnivore-herbivore
    • domestic
    • domestic herbavores raised with dogs
    • dogs feed on byproduct of butchered animals
    • sheep-raising areas heavily infected
    • VERY common
  17. How does echinococcosis infection typically occur (worldwide, multiple examples)
    • intimate contact w/ dogs (accidental ingestion of Echinococcus eggs) - MOST COMMON
    • Kenyan tribes eat dog intestine roasted over campfire (high rate of infection)
    • Nursing dogs "clean up mess" on children in Kenya (child infection)
    • Kenyans do not bury all dead - corpses fed on by wild dogs
    • Dog feces used in tanning solution in Lebanon, leads to infection by users
  18. Describe the symptoms of echinococcosis (a lot of info)
    • Effects of a hydatid cyst may not be apparent for MANY years (20+ years of slow growth)
    • symptoms include slowly increasing pressure in cyst area (resembles tumor growth)
    • *liver is most commonly affected organ
    • cysts in lungs (20-30%) can cause hempotysis (coughing up blood) and dyspnea (difficulty breathing)
    • cysts in brain/spinal cord (~3%) cause inflammatory response
    • osseous cysts (1-2%) lead to fragile/degraded bones
    • Cysts can become HUGE (>15L fluid) if growing in an unrestricted location
    • *NOTE- cysts can rupture, enter circulation, and produce secondary echinococcosis
    • ***anaphylactic shock occurs if hydatid fluid enters the blood stream (death is typically instantaneous)
  19. echinococcosis- diagnosis, treatment, prevention/control
    • diagnosis: often found during routine x-rays
    • CAT scans
    • hepatic hypertrophy / jaundice
    • immunological tests
    • treatment: surgical removal of cysts
    • hydatid fluid removed first
    • 2% formalin injected to kill protoscolises
    • formalin removed and cyst is removed
    • Mebendazole and/or Albendazole useful to prevent additional cyst growth after surgery
    • prevention/control: reduce contact between dogs and intermediate hosts
    • personal hygiene in relation to dog handling
    • treatment campaigns against adult tapeworm in dog (praziquantel)
    • sanitary disposal of offa/viscera of slaughtered food animals
    • public education
  20. define offal
    • The waste/leftovers from a slaughtered animal
    • Infective to dogs who eat offal of animals that had echinococcosis