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Parasitic Worms

Parasitic Worms. Pathogenic Human Helminthes and Arthropods. Characteristics. Multicellular Well developed organ systems Reproductive Dioecious Hermaphrodite Worldwide Tropical, subtropical Survival of eggs Survival of larval stages Less developed Sanitation

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Parasitic Worms

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  1. Parasitic Worms Pathogenic Human Helminthes and Arthropods

  2. Characteristics • Multicellular • Well developed organ systems • Reproductive • Dioecious • Hermaphrodite • Worldwide • Tropical, subtropical • Survival of eggs • Survival of larval stages • Less developed • Sanitation • Intermediate host survival

  3. Life Cycle • Host • Definitive • Intermediate • Cycle • Egg  ingestion • Larvae ingestion, penetration, migration • Infectious stage  intermediate host • Adultreproduces

  4. Overview of Generic Life Cycle

  5. Platyhelminths Flatworms Flukes Trematodes Flat, leaf shaped Suckers Named for location Tapeworms Cestodes Long body Scolex Proglottid Nematoda Roundworms Cylindrical body Cuticle Dioecious Roundworms Hookworms Pinworms Whipworms Strongyles Filaria Helminth Types

  6. Host Susceptibility

  7. Direct Damage Blockage Worm size Worm migration granulomas Pressure Tissue Necrosis Migration Turnover Indirect Damage Host response Inflammation Hypersensitivity Mucosal changes Pathogenesis

  8. PLATYHELMINTHS • Flat body • Hermaphrodites • Parasitic • Trematodes • Cestodes

  9. Schistostomiasis Fascioliasis Intestinal Fluke Chinese Liver Fluke Lung Fluke Life Cycle Eggs Miracidia Intermediate host Cercariae Second intermediate host Metacercariae Definitive host Adult fluke FLUKES (Trematodes)

  10. Fluke Anatomy and Life Cycle Miracidia Adult Fluke

  11. Fasciola hepatica Typical life cycle Snail intermediate host Humans exposed to metacercaria by eating watercress Intestine  Liver  Bile Ducts  eggs in feces Chinese Liver Fluke Typical life cycle Snail intermediate host Humans exposed to metacercaria by eating undercooked fish Intestine  Liver  Bile ducts eggs in feces Liver Flukes

  12. Flukes: Fasciola sp.

  13. Flukes of other Organs : Lungs • Paragonimus westermani • Eggs coughed and swallowed, passed in feces that contaminate water • Cercaria in snails • Metacercaria in crabs • Humans eat crabmeat • Adult flukes migrate from GI Blood  Lungs • Signs: Coughing Egg Adult Fluke

  14. Flukes of other Organs: Urine • Schistostoma • Eggs in urine, feces • Miracidia in snails • Cercaria in snails • Penetrate skin • Schistosomulae in liver • Adults migrate to urinary system • Signs: damage to liver, and urinary bladder

  15. Flukes • DX • Eggs in feces • TX • Antihelmenics • Prevention • Thoroughly cook meats • Cook vegetables

  16. TAPEWORMS: (Cestodes)

  17. Life Cycle of Tapeworms • Eggs in proglottids passed in stool • Larval phase in Intermediate host • Intestine  blood  Skeletal muscle and other tissue  cysts • Acquire by eating raw meat with cysts • Cysts  adult worms in intestines

  18. Tapeworm Anatomy Scolex with hooks Adult Tape worm Proglottids

  19. Taenia tapeworms • Taenia saginata (beef) • Taenia solium (pork) • Symptoms • Abdominal discomfort • Diagnosis • Worm segments • Eggs in stool • Treatment • Antihelminics • Prevention • Cook meat

  20. Taenia species

  21. Dipylidium canium • Dog / cat tapeworm • Zoonotic • Intermediate host • Flea • Children • Ingest • acquire

  22. Hydatid Disease • Echinococcus granulosus • Eggs ingested by herbivores • Embryos from eggs go to various sites to develop cysts • Ingestion of cysts or eggs • Humans intermediate host • Cyst • Damage due to size • Anaphylactic shock

  23. Ecchinococcus

  24. Tapeworm Summary • DX • Worm segments • Eggs in stool • TX • Antihelmenthics • Prevention • Hygiene • Inspect meat

  25. Tapeworms Taenia eggs Ecchinococcus Diplidium canium

  26. NEMATODES • “Roundworms” • Cyclindrical body • Dioecious • Cuticle

  27. Filaria Worms

  28. Elephantitis Wuchereia bancrofti Mosquito Lymphatics Microfilaria in blood Adults in LN Blockage Swelling Loaisis Onchocerca volvulus Biting flies CT Microfilaria in blood Adults in conjunctiva Inflammation swelling FILARIASIS

  29. Fliaria Summary • DX • Id microfilaria in blood • TX • Diethylcarbamazine • Prevention • Control of intermediate hosts Wuchereia bancrofti

  30. ASCARIASIS

  31. Roundworms • Ascaris lumbriocoides • Fecal contaminated food • Eggs ingested • Larvae released and migrate • GI  lymph/blood  lung alveoli  coughed  swallowed • Adults mature in upper GI (stomach and SI)

  32. Roundworms (Ascarids) • Symptoms • Asymptomatic • Respiratory • GI • DX • Eggs in stool • Adults in vomitus • TX • Prevention • Sanitation • Cook food

  33. Toxocariasis • Toxacaris canis, T. cati • Eggs in environment • Fecal  oral • Larvae hatch in GI  Blood  Liver  Lung  any tissue • aka Visceral Larval Migrans • Zoonosis

  34. Toxocariasis • Symptoms • Resp: cough, fever, wheezing • Organomegaly • Skin: rash • Eye: inflammation • DX • Blood work • Biopsy • Eggs in stool • TX • Prevention • Hygiene • Deworm animals

  35. Ancylostomaisis

  36. Hookworms • Ancylostoma, Necator • Eggs in feces hatch • Larvae mature in soil and penetrate skin • Skin  Lymphatic Blood  Lungs coughed & swallowed • Adults develop in SI by attaching mouth parts to lining  blood meals

  37. Hookworms • Symptoms • Skin rash, pruritic • Resp • GI: pain • Anemia • DX • Eggs / larvae in stool • TX • Prevention • Limit soil exposure

  38. Trichuriasis

  39. Whipworms • Trichuris trichura • Eggs in soil, ingestion of contaminated food • Larve hatch in SI, migrate to cecum • Larvae mature to adult stage

  40. Whipworm • Symptoms • GI: pain, diarrhea, bleeding, anemia, rectal prolapse • DX • Eggs in stool • Colonoscopy to view adults • TX : Antihelminthics • Prevention • Sanitation • Wash vegetables

  41. Pinworms • Enterobiasis vermicularis • Eggs @ perineum • Fecal-oral • Eggs hatch  Lower GI to mature • Female moves to perineal region to deposit eggs in sticky substance • HUMANS ONLY !! DX: GI itching, eggs Worms in colon TX: Anthelminthics Prevetion: Hygiene Wash clothing

  42. Trichinosis

  43. Trichinosis • Trichinella spiralis • Larvae in skeletal m. • Exposure by eating uncooked meat • Cyst  larvaeadult in intestine mature and release larvae • Larvae –> migrate using blood/lymph  penetrate muscles to form cysts

  44. Trichinosis • Symptoms • Asymptomatic • GI: cramps, diarrhea • Muscle: stiffness, pain, soreness • Skin: rash • Eyelid: swelling, pain, injected sclera • DX: symptomatic • TX • Prevention • Cook • Freeze

  45. Strongyloidiasis • Strongyloides stercoralis • Eggs hatch in SI mucosal glands • Larvae passed in stool • Exposure: larvae migrate through skin • Skin  Lungs  coughed and swallowed  Intestines • Larvae mature to adult stage Larva Adult

  46. Guinea Worm Disease • Drancunculus • Larvae in water • Crustacean (IH) • Humans ingest uncooked meat • Larvae released  skin  Adult in blister like lesion • Larvae produced and released with water

  47. Drancunculus removal

  48. Other Parasites

  49. Arthropod Parasites • Scabies • Sarcoptes scabeii • Mite • Burrows into skin • Lays eggs • Intense pruritis • Direct contact • Zoonosis • TX: insecticides

  50. Arthropod Parasites • Pediculosis • Human Lice • Head • Body • Direct contact • Blood meal • Eggs (nits) laid at base of hair shaft • Pruritis • TX: Insecticides Pediculus humanus

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