Author(s): Vernon Carruthers, Ph.D., Cary Engleberg, M.D., D.T.M.&H., 2009License: Unless otherwise noted, this material i...
Citation Key                                 for more information see: http://open.umich.edu/wiki/CitationPolicyUse + Shar...
Helmintic Infections          M1 Infectious Diseases Sequence                 Vernon Carruthers                   Cary Eng...
Infection vs. disease• successful parasites live in, but do not  kill their hosts• protozoa multiply within hosts  express...
Helminth forms                              LarvaEgg                              Cyst                                    ...
Helminth modes of entry• Ingestion (eggs or cysts)• Arthropod bites (larvae)• Penetration of intact skin or mucous membran...
Spread and tropisms• Some parasites must migrate to  certain locations within the host  in order to complete their life  c...
Cary Engleberg                 7
Mechanisms for evading the host response•  antigenic variation - trypanosomes, malaria,   giardia•  intracellular infectio...
Tissue damage and host             response• direct destruction of tissue• hypersensitivity reactions• eosinophila  – occu...
Classification of helminthsNematodes (roundworms)Platyhelminthes (flatworms)   Trematodes ( flukes )   Cestodes ( tapeworm...
Helmintic diseases             • Intestinal               – Others               – Strongyloides   (autoinfection cycle)ro...
Intestinal nematodes                                           Adult worms in the                                         ...
Strongyloides life cycle                               Adult worms in the                                 the intestine   ...
Source Undetermined                      14
Strongyloides - clinical features• uncomplicated  – GI upset• autoinfection• hyperinfection  – rash  – bronchspasm, chest ...
Trichinosis              16
Trichinella spiralis - life cycle•  cycle of carnivorism among hogs and rats•  humans ingest encysted larvae in infected, ...
Source Undetermined   Source Undetermined                                            18
Trichinosis cases, by source of      infection, U.S.,1981  Pork products    sausage               93    other             ...
Clinical features of trichinosis• Most common sxs:  – muscle pain and tenderness  – fever +/- chills  – edema (often perio...
Treatment of trichinosis• antihelmintic (albendazole) to kill  any intestinal adults• steroids to relieve inflammatory  re...
Filaria          22
Life cycles of two types of                            filaria                     Arthropod       Adult            Larvae...
Microfiliaria found in the blood of     lymph dwelling species Armed Forces Institute of Pathology                        ...
Long-termconsequences ofpersistent lymph-dwelling filarialinfection:Blockage of lymphdrainage withchronic lymphedema(eleph...
Source Undetermined                      26
Life cycles of two types of                            filaria                     Arthropod       Adult            Larvae...
Source UndeterminedBlack fly: vector of Onchocerciasis                                      28
O. volvulus microfilaria (a skin-                     dwelling species) in skin snip      Snip site                       ...
Cary Engleberg                 30
Source UndeterminedO. volvulus skin nodule removed and sectioned,  showing cross-sections of male and female     adult wor...
Source Undetermined  Onchocerciasis ( River blindness )   32
Role of endosymbiont Wohlbachia      sp. in filiaria infection• Rickettsia-like organisms required  for fecundity and viab...
Schistosomiasis                  34
Geographic distribution of                     schistosomiasis                           S. mansoni                       ...
Schistosomiasis - life cycle                                                                      EggsCercaria            ...
Source Undetermined  Source Undetermined        Source UndeterminedS. mansoni              S. haematobium             S. j...
Source Undetermined                      38
Events following cercarial penetration1.  Larva migrate to lungs and develop as      schistosomulae (this may trigger a se...
Immune response to          schistosoma infectionSource Undetermined                                  40
Source Undetermined                      41
Source Undetermined                      42
Source Undetermined                      43
Source Undetermined                      44
Source Undetermined                      45
Source Undetermined        pipestem fibrosis                            46
Source Undetermined                      47
Schistosomiasis - pathogenesis• egg granuloma (type IV reaction)--> fibrosis• morbidity ~ worm (egg) burden• concomitant i...
Schistosomiasis- clinical features• Cercarial dermatitis• Intestinal schistosomiasis (granulomas --> polyps, protein loss,...
Drug treatment of         schistosomiasis• Praziquantel increases permeability  of adult parasite to Ca++.• Tetanospasm --...
Cestode infections                     51
Tapeworms• Definitive hosts: harbor adult worms• Intermediate hosts: harbor tissue cysts  (containing worm heads)• Humans ...
Taeniasis                                                             poor                                                ...
Source Undetermined                      54
Source Undetermined                      55
Source Undetermined                      56
Source Undetermined                      57
Cysticerci         Hydatid CystC. Engleberg/V. Carruthers                                            58
Isolated cysticerci      Hydatid cyst                         Source Undetermined   Source Undetermined                   ...
Source UndeterminedDuane Newton          60
Echinococcosis                       ingestion of                                     eggs in                             ...
Cary Engleberg                 62
Treatment of cysticercosis and       echinococcosis• Antihelminthic therapy (e.g.,  albendazole, praziquantel)• (Echinococ...
Comparison of pork tapeworm            and Echinococcus life cycles  Definitive    hosts                     Dog      Dead...
Additional Source Information                                   for more information see: http://open.umich.edu/wiki/Citat...
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04.30.09: Helmintic Infections

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04.30.09: Helmintic Infections

  1. 1. Author(s): Vernon Carruthers, Ph.D., Cary Engleberg, M.D., D.T.M.&H., 2009License: Unless otherwise noted, this material is made available under the terms of theCreative Commons Attribution 3.0 License: http://creativecommons.org/licenses/by/3.0/We have reviewed this material in accordance with U.S. Copyright Law and have tried to maximize your ability to use, share, and adapt it.The citation key on the following slide provides information about how you may share and adapt this material.Copyright holders of content included in this material should contact open.michigan@umich.edu with any questions, corrections, orclarification regarding the use of content.For more information about how to cite these materials visit http://open.umich.edu/education/about/terms-of-use.Any medical information in this material is intended to inform and educate and is not a tool for self-diagnosis or a replacement for medicalevaluation, advice, diagnosis or treatment by a healthcare professional. Please speak to your physician if you have questions about yourmedical condition.Viewer discretion is advised: Some medical content is graphic and may not be suitable for all viewers.
  2. 2. Citation Key for more information see: http://open.umich.edu/wiki/CitationPolicyUse + Share + Adapt { Content the copyright holder, author, or law permits you to use, share and adapt. } Public Domain – Government: Works that are produced by the U.S. Government. (17 USC § 105) Public Domain – Expired: Works that are no longer protected due to an expired copyright term. Public Domain – Self Dedicated: Works that a copyright holder has dedicated to the public domain. Creative Commons – Zero Waiver Creative Commons – Attribution License Creative Commons – Attribution Share Alike License Creative Commons – Attribution Noncommercial License Creative Commons – Attribution Noncommercial Share Alike License GNU – Free Documentation LicenseMake Your Own Assessment { Content Open.Michigan believes can be used, shared, and adapted because it is ineligible for copyright. } Public Domain – Ineligible: Works that are ineligible for copyright protection in the U.S. (17 USC § 102(b)) *laws in your jurisdiction may differ { Content Open.Michigan has used under a Fair Use determination. } Fair Use: Use of works that is determined to be Fair consistent with the U.S. Copyright Act. (17 USC § 107) *laws in your jurisdiction may differ Our determination DOES NOT mean that all uses of this 3rd-party content are Fair Uses and we DO NOT guarantee that your use of the content is Fair. To use this content you should do your own independent analysis to determine whether or not your use will be Fair.
  3. 3. Helmintic Infections M1 Infectious Diseases Sequence Vernon Carruthers Cary EnglebergSpring 2009
  4. 4. Infection vs. disease• successful parasites live in, but do not kill their hosts• protozoa multiply within hosts expression of disease depends on host factors• helminths do not multiply within hosts severity of disease depends on parasite burden and immunologic response to parasites 3
  5. 5. Helminth forms LarvaEgg Cyst Adults 4 C. Engleberg/V. Carruthers
  6. 6. Helminth modes of entry• Ingestion (eggs or cysts)• Arthropod bites (larvae)• Penetration of intact skin or mucous membranes (larvae) 5
  7. 7. Spread and tropisms• Some parasites must migrate to certain locations within the host in order to complete their life cycle• Non-human parasites, in humans, often fail to migrate properly and become dead-end infections 6
  8. 8. Cary Engleberg 7
  9. 9. Mechanisms for evading the host response•  antigenic variation - trypanosomes, malaria, giardia•  intracellular infection - malaria, toxoplasma•  encystation* - Toxoplasma, cestodes•  camouflage - schistosomes•  cleavage of ABs or C components - amoebae, leishmania•  suppression/redirection of the cellular immune response - malaria, leishmania, schistosomes * cyst has multiple meanings 8
  10. 10. Tissue damage and host response• direct destruction of tissue• hypersensitivity reactions• eosinophila – occurs with helminths, not protozoa – results from tissue migration 9
  11. 11. Classification of helminthsNematodes (roundworms)Platyhelminthes (flatworms) Trematodes ( flukes ) Cestodes ( tapeworms )C. Engleberg/V. Carruthers 10
  12. 12. Helmintic diseases • Intestinal – Others – Strongyloides (autoinfection cycle)roundworms • Invasive – Trichinosis (muscle pain, uncooked carnivores) – Filaria (worms in lymphatics or under skin) flukes – Schistosomiasis (liver or urinary tract granulomas and fibrosis) tapeworms – Cysticercosis (cysts in brain, seizures) – Echinococcus (massive cysts in liver or lung) 11
  13. 13. Intestinal nematodes Adult worms in the the intestine Larvae pass through lungs Trichiuris (whipworm) Enterobius (pinworm)Larvae enter Eggsbloodstream Eggs ingested ascaris strongyloides hookworm Larvae hatch Larvae penetrate from eggs through intact skinC. Engleberg/V. Carruthers 12
  14. 14. Strongyloides life cycle Adult worms in the the intestine Larvae pass through lungsLarvae enter Eggsbloodstream Autoinfection 1st stage Larvae penetrate larvae hatch through intact skin Larvae molt from eggs twice to form filariform larvae 13C. Engleberg/V. Carruthers (infectious)
  15. 15. Source Undetermined 14
  16. 16. Strongyloides - clinical features• uncomplicated – GI upset• autoinfection• hyperinfection – rash – bronchspasm, chest X-ray infiltrates – diarrhea – profound eosinophilia – recurrent Gram-negative bacteremia 15
  17. 17. Trichinosis 16
  18. 18. Trichinella spiralis - life cycle•  cycle of carnivorism among hogs and rats•  humans ingest encysted larvae in infected, undercooked pork•  larvae exist in stomach and burrow into small intestinal mucosa•  adult males and female reemerge and produce larvae which penetrate intestine and circulate in bloodstream•  larvae enter skeletal muscle cells and encyst 17
  19. 19. Source Undetermined Source Undetermined 18
  20. 20. Trichinosis cases, by source of infection, U.S.,1981 Pork products sausage 93 other 44 unspecified 9 Non-pork products hamburger 18 bear 10 other wild animals 7 Unknown 7 188 19
  21. 21. Clinical features of trichinosis• Most common sxs: – muscle pain and tenderness – fever +/- chills – edema (often periorbital)• >10% eosinophilia (often ~50%)• elevated creatine phosphokinase (CPK)• +/- chronic neurologic/myocardial sxs• self-limited (2% mortality) 20
  22. 22. Treatment of trichinosis• antihelmintic (albendazole) to kill any intestinal adults• steroids to relieve inflammatory reactions• antipyretics 21
  23. 23. Filaria 22
  24. 24. Life cycles of two types of filaria Arthropod Adult Larvae vector worm pairs (microfilariae)Lymph- mosquitoes peripheral circulate dwelling lymphatics in bloodstream(e.g, Wuchereria bancroftii )Skin- biting flies skin nodules migrate through dwelling or migratory dermis 23
  25. 25. Microfiliaria found in the blood of lymph dwelling species Armed Forces Institute of Pathology 24
  26. 26. Long-termconsequences ofpersistent lymph-dwelling filarialinfection:Blockage of lymphdrainage withchronic lymphedema(elephantiasis) Source Undetermined 25
  27. 27. Source Undetermined 26
  28. 28. Life cycles of two types of filaria Arthropod Adult Larvae vector worm pairs (microfilariae)Lymph- mosquitoes peripheral circulate dwelling lymphatics in bloodstream(e.g, Wuchereria bancroftii )Skin- biting flies skin nodules migrate through dwelling or migratory dermis(e.g., Onchocerca volvulus & Loa loa ) 27
  29. 29. Source UndeterminedBlack fly: vector of Onchocerciasis 28
  30. 30. O. volvulus microfilaria (a skin- dwelling species) in skin snip Snip site Source Undetermined Depigmentation due to chronic microfilarial production, degradation, and allergic host responses in the skinCary Engleberg 29
  31. 31. Cary Engleberg 30
  32. 32. Source UndeterminedO. volvulus skin nodule removed and sectioned, showing cross-sections of male and female adult worms (source of microfiliariae) 31
  33. 33. Source Undetermined Onchocerciasis ( River blindness ) 32
  34. 34. Role of endosymbiont Wohlbachia sp. in filiaria infection• Rickettsia-like organisms required for fecundity and viability of filaria• Wohlbachia-free worms produce less inflammation in tissue (? LPS)• Implications for rx: – ivermectin kills microfilaria only – tetracycline may destroy adult worms 33
  35. 35. Schistosomiasis 34
  36. 36. Geographic distribution of schistosomiasis S. mansoni S. hematobium S. japonicum 35Cary Engleberg
  37. 37. Schistosomiasis - life cycle EggsCercaria S.m. S.h. S.j.(snail) Pearson Scott Foresman, wikimedia commons 36Cary Engleberg (All other images)
  38. 38. Source Undetermined Source Undetermined Source UndeterminedS. mansoni S. haematobium S. japonicum 37
  39. 39. Source Undetermined 38
  40. 40. Events following cercarial penetration1.  Larva migrate to lungs and develop as schistosomulae (this may trigger a self- limited febrile illness).2.  Male and female schistomulae migrate to the abdominal venules: I.  Superior mesenteric (S. japonicum) II.  Inferior mesenteric (S. mansoni) III.  Bladder plexus (S. hematobium)3.  Males and females pair off and egg production begins4.  Eggs migrate out of the body through visceral organs or become trapped and die in tissues. 39
  41. 41. Immune response to schistosoma infectionSource Undetermined 40
  42. 42. Source Undetermined 41
  43. 43. Source Undetermined 42
  44. 44. Source Undetermined 43
  45. 45. Source Undetermined 44
  46. 46. Source Undetermined 45
  47. 47. Source Undetermined pipestem fibrosis 46
  48. 48. Source Undetermined 47
  49. 49. Schistosomiasis - pathogenesis• egg granuloma (type IV reaction)--> fibrosis• morbidity ~ worm (egg) burden• concomitant immunity to schistosomula• adult worms: invisible to the immune system (survive for years) 48
  50. 50. Schistosomiasis- clinical features• Cercarial dermatitis• Intestinal schistosomiasis (granulomas --> polyps, protein loss, malabsorption, strictures)• Hepatosplenic schistosomiasis (portal hypertension --> ascites, varices, splenomegaly, normal hepatic function)• Urinary schistosomiasis (hematuria, chronic infection, obstruction)•  Other (cardiopulmonary, CNS, etc.) 49
  51. 51. Drug treatment of schistosomiasis• Praziquantel increases permeability of adult parasite to Ca++.• Tetanospasm --> death 50
  52. 52. Cestode infections 51
  53. 53. Tapeworms• Definitive hosts: harbor adult worms• Intermediate hosts: harbor tissue cysts (containing worm heads)• Humans acquire infection two ways: – ingestion of eggs from feces (to acquire tissue cysts) = Intermediate host – ingestion of tissue cysts in undercooked meat (to acquire a tapeworm) = Definitive host 52
  54. 54. Taeniasis poor sanitation ingestion of undercooked pork poor hygiene Tapeworm Cysticercosis(pig) Martin von Nathusius, wikimedia commons 53 Cary Engleberg (All other images)
  55. 55. Source Undetermined 54
  56. 56. Source Undetermined 55
  57. 57. Source Undetermined 56
  58. 58. Source Undetermined 57
  59. 59. Cysticerci Hydatid CystC. Engleberg/V. Carruthers 58
  60. 60. Isolated cysticerci Hydatid cyst Source Undetermined Source Undetermined 59
  61. 61. Source UndeterminedDuane Newton 60
  62. 62. Echinococcosis ingestion of eggs in pastures ingestion of entrails contact with dogs (dog) Abujoy, wikimedia commons Cystic Hydatid Disease (sheep) wikimedia commons 61 Cary Engleberg (All other images)
  63. 63. Cary Engleberg 62
  64. 64. Treatment of cysticercosis and echinococcosis• Antihelminthic therapy (e.g., albendazole, praziquantel)• (Echinococcus only) – Surgical removal – Irrigation-evacuation of cysts 63
  65. 65. Comparison of pork tapeworm and Echinococcus life cycles Definitive hosts Dog Dead-end (adult Human hosts tapeworms) Human HumanIntermediate hosts Sheep(tissue cysts) PigC. Engleberg/V. Carruthers 64
  66. 66. Additional Source Information for more information see: http://open.umich.edu/wiki/CitationPolicySlide 5: Cary Engleberg and Vernon CarruthersSlide 8: Cary EnglebergSlide 11: Cary Engleberg and Vernon CarruthersSlide 13: Cary Engleberg and Vernon CarruthersSlide 14: Cary Engleberg and Vernon CarruthersSlide 15: Source UndeterminedSlide 19: Sources UndeterminedSlide 25: Armed Forces Institute of Pathology, http://www.afip.org/index.htmlSlide 26: Source UndeterminedSlide 27: Source UndeterminedSlide 29: Source UndeterminedSlide 30: Cary Engleberg (left) Sources Undetermined (right)Slide 31: Cary EnglebergSlide 32: Source UndeterminedSlide 33: Source UndeterminedSlide 36: Cary EnglebergSlide 37: (snail) Pearson Scott Foresman, Wikimedia Commons, http://commons.wikimedia.org/wiki/File:Snail_(PSF).png; Cary Engleberg All other images)Slide 38: Sources UndeterminedSlide 39: Source UndeterminedSlide 41: Source UndeterminedSlide 42: Source UndeterminedSlide 43: Source UndeterminedSlide 44: Source UndeterminedSlide 45: Source UndeterminedSlide 46: Source UndeterminedSlide 47: Source UndeterminedSlide 48: Source UndeterminedSlide 54: (pig) Martin von Nathusius, Wikimedia Commons, http://commons.wikimedia.org/wiki/File:Cochon.svg; Cary Engleberg (All other images)Slide 55: Source UndeterminedSlide 56: Source UndeterminedSlide 57: Source UndeterminedSlide 58: Source UndeterminedSlide 59: Cary Engleberg and Vernon CarruthersSlide 60: Sources UndeterminedSlide 61: Duane Newton, University fo MichiganSlide 62: (dog) Abujoy, Wikimedia Commons, http://commons.wikimedia.org/wiki/File:Dog_silhouette.svg, CC:BY-SA, http://creativecommons.org/licenses/by-sa/2.5/deed.en ; (sheep) Wikimedia Commons, http://commons.wikimedia.org/wiki/File:LA2-Blitz-Ostfriesisches_Milchschaf.png ; Cary Engleberg (All other images)Slide 63: Cary EnglebergSlide 65: Cary Engleberg and Vernon Carruthers

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