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Journal 10/18. Explain why you should care about the invasive species of flatworm called bipalium ? How would an invasion of this worm affect you personally? Get out your “Plethora of Planaria” lab so we can take day 2 observations . UNIT 3A- PHYLUM PLATYHELMINTHES.
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Journal 10/18 • Explain why you should care about the invasive species of flatworm called bipalium? How would an invasion of this worm affect you personally? • Get out your “Plethora of Planaria” lab so we can take day 2 observations
UNIT 3A- PHYLUM PLATYHELMINTHES Parasitic Flukes & Tapeworms
CLASS TREMATODA • Common name- flukes • Endoparasitic- live inside host • Wide, flat with oval or elongate bodies • Have 2-3 hosts • Intermediate hosts- where asexual part of life cycle occurs • Definitive host- final host where sexual part of life cycle occurs • Almost all adult flukes are parasites of vertebrates (fish, frogs, turtles, livestock, and humans) • Internal anatomy is similar to Turbellarians (planarians).
CLASS TREMATODAEX: Liver Flukes • Types: • Chinese liver fluke- common parasite of humansthat live in Asia. • Sheep liver fluke- common in sheep or people who raise sheep • Lives in the liver where it eats tissue & blood. • Contracted by • Eating uncooked contaminated food (sushi) • Eating water plants (water cress)infected with larvae
CLASS TREMATODAEX: Liver Fluke • Signs & Symptoms: • Enlarged liver • Feeling of fullness • Abdominal discomfort • Jaundice • Fatigue • Weakness • Nausea • Weight loss • Detection: look for eggs in stool or larvae in blood • Treatment: triclabendazole
Liver Fluke Life Cycle • Eggs passed out w/feces • Eggs ingested by a snail- the first intermediate host. • Inside the snail, the eggs undergo asexual reproduction & metamorphosis • Miracidia- cilia for swimming • Sporocysts- asexual reprod. • Rediae- worm like stage • Cercariae- has tail for swimming • Free swimming cercariae burrow out of skin of snail and search out fish or plant- the second intermediate host. • Cercariae encyst in fish/plant and are called metacercariae which is then ingested by a human or other vertebrate. • Metacercariaeexcyst in the intestine and migrate to the liver where they live, feed & reproduce sexually.
CLASS TREMATODAEX: Blood Flukes • Common in Africa, Asia, S. America • Cause disease known as Schistosomiasis(A.K.A. bilharzia) • Symptoms: • Fever & chills • lymph node enlargement • liver and spleen enlargement • frequent urination, blood in urine and in stool • Invasion in skin may cause rash (swimmer’s itch)
CLASS CESTODA • Common name: tapeworms • Endoparasitic: live inside host • Long, flat ribbon-like bodies • White w/shades of yellow or gray • Size: 1mm to 15 m in length (up to 60 ft!)
CLASS CESTODA 6. Body Structure • Scolex- head-like structure; hooks & suckers for attachment (not feeding) • Neck- contains immatureproglottids- series of repeating units of reproductive organs. • Strobila- rest of body; contains proglottids that are mature and gravid- full of eggs.
CLASS CESTODA 7. Digestion a. No mouth or digestive tract. b. Absorbnutrients directly across their body wall.
CLASS CESTODA • Signs/Symptoms: • Nausea & Weakness • Loss of appetite • Weight loss & diarrhea • Inadequate absorption of nutrients in food • Can lead to Cysticercosis disease in humans where larvae encyst in your muscle. • These cysts can end up in brain and cause death. • Detection: MRI or Xrayscan detect cysts in muscle. • Treatment: Depends on infection & location of cysts. Albendazole and anti-inflammatory drugs help but surgical removal may be necessary.
California had the highest percentage of fatal cysticercosis from 1990-2002!
Life Cycle of a Tapeworm • Eggs or gravid proglottids are passed with feces into environment. • Cows, pigs, fish ingest eggs/gravid proglottids from vegetation in environment. • Oncospheres (larva) hatch in intestine, burrow thru intestinal wall, and enter circulatory system where they end up in muscle where they become a bladderworm inside a cyst. • Humans are infected by ingesting uncooked infected meat. • Bladderworm will hatch in stomach and migrate to intestine where they attach to intestinal wall with hooks and suckers and begin absorbing nutrients. • Adults sexually reproduce in final vertebrate host (human)
Life Cycle of Tapeworm in Dog • Tapeworm inside fleas • Dog chews when flea bites and ingests fleas • Dog may also eat feces infected with tapeworm eggs/proglottids • Tapeworm Lifecycle Movie - YouTube
Environmental/Economic Significance of Parasitic Flatworms • Cause disease in vertebrates in many countries • Must study the worms to figure out how to treat infected people.