Parasitology Review


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Parasitology Review by Margie Morgan

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  • Particularly difficult to differentiate from falciprium
  • Hallmark of babesiosis is the tetrad (Maltese cross; cruciform body)
  • Blackwater fever (falciprium and think black pee)
  • Microscopic examination
  • Exception for non-falcirpium is P. vivax where chlorquine resistance is seen in Papua New Guinea and Indonesia
  • The malaria parasite life cycle involves two hosts.  During a blood meal, a malaria-infected female Anopheles mosquito inoculates sporozoites into the human host.  Sporozoites infect liver cells and mature into schizonts, which rupture and release merozoites.  (Of note, in P. vivax and P. ovale a dormant stage [hypnozoites] can persist in the liver and cause relapses by invading the bloodstream weeks, or even years later.)  After this initial replication in the liver (exo-erythrocytic schizogony ), the parasites undergo asexual multiplication in the erythrocytes (erythrocytic schizogony ).  Merozoites infect red blood cells .  The ring stage trophozoites mature into schizonts, which rupture releasing merozoites.  Some parasites differentiate into sexual erythrocytic stages (gametocytes).  Blood stage parasites are responsible for the clinical manifestations of the disease. The gametocytes, male (microgametocytes) and female (macrogametocytes), are ingested by an Anopheles mosquito during a blood meal .  The parasites’ multiplication in the mosquito is known as the sporogonic cycle .  While in the mosquito's stomach, the microgametes penetrate the macrogametes generating zygotes .  The zygotes in turn become motile and elongated (ookinetes) which invade the midgut wall of the mosquito where they develop into oocysts .  The oocysts grow, rupture, and release sporozoites , which make their way to the mosquito's salivary glands.  Inoculation of the sporozoites into a new human host perpetuates the malaria life cycle . 
  • Presence of absence of various stages in the blood
    Morphology of the gametocyte
    Size of the infected RBC
  • Most prevalent
    Widest geographical distribution
  • Enlarged RBC; fimbriated/ragged rbc
  • Fever cycle every 72 hours (quartan), can remain dormant in the blood for years.
    Untreated infections may last as long as 20 years
  • P
  • Parasitology Review

    1. 1. Parasitology Review Margie Morgan
    2. 2. Clinical presentation      Travel history or poor sanitation put you at the highest risk for parasitic infection Sporadic symptoms, Poor immune status higher risk Dysentery not common (amebiasis) Most usual symptoms: • Abdominal pain, cramping, long term nausea, and malaise, mucous in stool, and +/- fever
    3. 3. Laboratory Diagnosis   Limited Currently based on microscopic exam, however utility/availability of: molecular panels are in the • Serology near future • Stool • Fluorescent stains • Non-stool • PCR  Perianal specimen       • • Sigmoidoscopic specimen Duodenal aspirates Liver abscess Sputum Urine Urogenital Blood Tissue
    4. 4. Two-vial collection kit for Stool 10% formalin  Concentration with ethyl acetate to eliminate fecal debris  Wet mount and DFA staining  Helminth eggs, larvae, microsporidia, and protozoan cysts PVA with fixative  Polyvinyl alcohol  Permanent stained smear • Trichrome stain   Protozoan trophozoites and cysts Mercury based fixatives being phased out for safety – Zinc fixatives are now used
    5. 5. Most Common Pathogens  Protozoa • Intestinal & urogenital  E histolytica, Blastocystis hominis, Giardia lamblia, Dientamoeba fragilis, Balantidium coli, Cryptosporidium sp., Cyclospora sp, Cyclospora, (Isospora) belli, and Microsporidia • Blood & tissue     Plasmodium, Babesia, Trypanosomes Toxoplasma gondii, Leishmania Naegleria, Acanthamoeba, Balamuthia Helminths • Nematodes  Ascaris, Trichuris, hookworm, pinworm, and Strongyloides • Cestodes  Taenia, Hymenolepis, Diphyllobothrium • Trematodes  Fasciola, Fasciolopsis, Schistosoma, Paragonimus, Clonorchis
    6. 6. PROTOZOA  Amebae (found in stool) • • • • •  Entamoeba coli Entamoeba histolytica Endolimax nana Iodamoeba butschlii Dientamoeba fragilis Ciliates, Coccidia, Blastocystis • • • • • • • Balantidium Cryptosporidium Isospora belli Sarcocystis Cyclospora Microsporidium Blastocystis hominis Blood-Borne Protozoa • • • • • Flagellates (found in stool) • Giardia lamblia • Chilomastix mesnili    Babesia Leishmania Trypanosoma brucei T. cruzi Plasmodium Other • • • Toxoplasma Naegleria fowleri Acanthamoeba
    7. 7. Protozoa Found in Stool: Amebae pathogen
    8. 8. Intestinal amoeba Entamoeba coli  Entamoeba histolytica/dispar  Entamoeba hartmanni  Endolimax nana  Iodamoeba butschlii 
    9. 9. Entamoeba histolytica/dispar   E. histolytica is a pathogen and E. dispar is a nonpathogenic species that can also occur in the large intestine. Morphologically indistinguishable E histolytica • Cysts = infectious form • trophozoites = invasive form • Contaminated water and poor sanitation • Colon biopsy shows “flask-shaped” ulcer • Non-intestinal disease = extraintestinal amebiasis (liver abscess)  Serology
    10. 10. Entamoeba histolytica/dispar Cysts <= 10 um In diameter Up to 4 nuclei in the cyst Clean chromatin Bulls-eye nucleoli
    11. 11. Entamoeba histolytica/dispar Trophozoites & Trophozoite with ingested rbcs Cysts
    12. 12. Amebic abscess Amebic liver abscess Entamoeba histolytica Serology – high % positive in extraintestinal cases Flask-shaped ulcer of intestinal amebiasis
    13. 13. Entamoeba coli cyst and trophozoite Trophozoite is the form that invades intestines Cyst >=15 mm Up to 8 nuclei Shed from host Lives in environment Nucleus has a chromatin ring The cytoplasm appears dirty
    14. 14. Entamoeba coli Trophozoites & Cysts
    15. 15. Endolimax nana trophozoite Mostly thought to be a non-pathogen, Seen in HIV/AIDS patients, Some literature suggesting it can cause intermittent or chronic diarrhea
    16. 16. Iodamoeba butschlii cysts with starch Staining inclusion Iodine preparation – name from appearance with iodine staining
    17. 17. Flagellates Giardia lamblia  Dientamoeba fragilis  Trichomonas vaginalis 
    18. 18. Protozoa Found in Stool: Flagellates
    19. 19. Giardia lamblia       Contaminated water, undercooked foods Mild diarrhea to severe malabsorption Foul, watery diarrhea Day-care center outbreaks Cysts/trophozoites may be seen in stool, but can be hard to find; Fluorescent stains available Duodenal aspirations CYSTS TROPHOZOITE “falling leaf” motility
    20. 20. Giardia lamblia trophozoite Waxing and waning symptoms Can be irregularly Shed in stool material & can be difficult to find Russia & Mexico -Hot beds Only invades intestine Flagyl (Metronidazole) is drug of choice
    21. 21. Giardia lamblia cysts
    22. 22. Giardia lamblia cysts
    23. 23. Giardia lamblia trophozoites
    24. 24. Only invades intestinal tissue
    25. 25. Chilomastix mesnili cyst    Nonpathogen Mimics Giardia lamblia cyst – except for clear space at end of cyst Internal structure looks like “shepherd’s crook” or safety pin
    26. 26. Chilomastix mesnili cyst Clearing Nipple Chilomastix mesnili trophozoite
    27. 27. Dientamoeba fragilis Diarrhea, anal pruritus  Co-infection with Enterobius (pinworm) 
    28. 28. Trichomonas vaginalis    Urogenital protozoan Scant, watery vaginal discharge Four flagella, short undulating membrane
    29. 29. Protozoa Found in Stool: Ciliates, Coccidia, Blastocystis
    30. 30. Ciliates  Balantidium coli • Mainly in swine • Contact with swine & poor hygiene • Only ciliate that’s pathogenic to humans • Similar disease as amebiasis, but extraintestinal invasion rare • Largest (50-200 um) trophozoite; surface covered with cilia; macronucleus • Cyst 40-60 um • Readily identified in fresh, wet mounts
    31. 31. Only protozoa with cilia 50 microns In intestine can cause flask-shaped ulcers like those caused by E. histolytica
    32. 32. Intestinal Sporozoa (coccidia) Isospora  Cryptosporidium  Cyclospora  Sarcocystis  } All are Partial acid fast +
    33. 33. Isospora belli     Contaminated food/water, oral-anal Found most commonly in HIV/AIDS Infects intestinal epithelium Malabsorption syndrome mimicking giardiasis Modified acid fast stain
    34. 34. Isospora belli
    35. 35. Cryptosporidium parvum Contaminated water  Resistant to usual water-purification procedures (chlorination, ozone)  Daycare center outbreaks (fecal-oral)  Watery diarrhea; more severe in AIDS 
    36. 36. Cryptosporidium Partial Acid Fast Positive
    37. 37. Enzyme immunoassay for the antigen Direct Fluorescence Antibody stain – of C. parvum is also available. Cryptosporidium parvum False negatives may result due to low organisms numbers (Asymptomatic carriers) in both the EIA and DFA assays Combo stain for Cryptosporidium And Giardia lamblia C. parvum Giardia
    38. 38. C. Parvum in intestine C. Parvum in intestine just below the plasma membrane
    39. 39. Cyclospora cayetanensis Contaminated fruits and vegetables  Watery diarrhea; more sever in HIV/AIDS  Infects upper small bowel  Found in vacuoles in cytoplasm of jejunal epithelium, villous atrophy, crypt hyperplasia 
    40. 40. Cyclospora cayetanensis PAF + 6-8 microns Autofluorescence on FA scope Also positive on Calcofluor white stain
    41. 41. Microsporidia        Obligate intracellular pathogen Enterocytozoon and Encephalitozoon species Primitive eukaryotic organism (fungi) Many genera Infection by ingestion of spores Chronic diarrhea in AIDS patients Myositis, hepatitis, peritonitis, keratitis
    42. 42. Microsporidia -Common in HIV/AIDS -Watery persistent diarrhea Positive on modified Trichrome and Calcofluor white stains -Longer staining time will eventually allow for it to work its way into the spore
    43. 43. Blastocystis hominis cysts Nuclear blobs Around the periphery     Can be a pathogen Small #s: can be commensal Large #s: pathogenic Dirty H20  Traveler’s diarrhea Trichrome stain Iodine wet mount
    44. 44. Blood-Borne Protozoa Organism Transmission Disease/Symptoms Diagnosis Treatment Trypanosoma brucei Tsetse fly African trypanosomiasis; Sleeping sickness Encephalitis; cardiac failure Hemoflagellate in blood or lymph node Blood stage: Suramin or petamidine isethionate T. cruzi Reduvid (kissing) bug American trypanosomiasis; Chagas disease: megacolon, cardiac failure. Hemoflagellate in blood or tissue. C- or commashaped CNS: melarsoperol Nifurtimox and Benzonidazole. Leishmania donovani Phlebotomine sandfly Visceral leishmaniasis (Kala-azar), granulomatous skin lesions Iraq/Iran/Afghanistan Intracellular (macrophages) leishmanial bodies with kinetoplast Pentosam; Pentamidine isethionate. Babesia microti Ixodes tick Hemolytic anemia, Jaundice, fever, hepatomegaly Maltese cross in rbc None; self resolving.
    45. 45. Trypanosomes  2 different diseases • Chagas disease (American trypanosomiasis) Trypanosoma cruzi  Reduviid / Triatome (kissing) bug  • African sleeping sickness (African trypanosomiasis) T. brucei (gambiense and rhodesiense)  Tsetse fly 
    46. 46. Trypanosoma brucei  Sleeping sickness (African trypanosomiasis)   Vector: Tsetse fly The two T. brucei species that cause African trypanosomiasis are indistinguishable morphologically • T. b. gambiense • T. b. rhodesiense  A typical trypomastigote has: • A small kinetoplast located at the posterior end • A centrally located nucleus • An undulating membrane, and • A flagellum running along the undulating membrane, leaving the body at the anterior end • 14 to 33 µm in length  Trypomastigotes are the only stage found in patients.
    47. 47. Trypanosoma brucei gambiense in a blood film Filamentous structures found in blood
    49. 49. Trypanosoma cruzi  Chagas (American trypanosomiasis)     Vector: Reduvid/Triatoma (kissing) bug Trypomastigotes are the only stage found in the blood of an infected person; may be seen in CSF in CNS infections Motile circulating trypomastigotes are readily seen on slides of fresh anticoagulated blood in acute infection but are rarely detectable by microscopy in chronic T. cruzi infection. A typical trypomastigote has: • • • • A large, subterminal or terminal kinetoplast, A centrally located nucleus, An undulating membrane, and A flagellum running along the undulating membrane, leaving the body at the anterior end. • 12 to 30 µm in length.  Amastigote stage parasite may be seen in histopathology specimens from affected organs. C-shape
    50. 50. Reduvid bug Trypanosoma cruzi - Possible cardiac infiltration->Chagas
    51. 51. Leishmania Obligate intracellular parasite  Vector: female sand fly bite  Visceral leishmaniasis (kala azar)  • L. donovani  Cutaneous leishmaniasis • L. • L. tropica braziliensis
    52. 52. Leishmania
    53. 53.  Leishmania amastigotes • Macrophages filled with amastigotes (arrows), several of which have a clearly visible nucleus and kinetoplast • Amastigotes are being freed from a rupturing macrophage
    54. 54. Leishmania – Clinical Disease   Cutaneous • Single or few chronic, ulcerating lesions; many species • Latin America, southern Europe, Middle east, southern Asia, Africa • Mucocutaneous in Latin America Visceral • primarily L. donovani complex (Asia), L. infantum/chagasi (Africa and Latin America), others • Hepatosplenomegaly, anemia, cytopenias, systemic symptoms • India, Bangladesh, Nepal, Sudan, and Brazil • Important OI in HIV infection
    55. 55. Leishmania  Diagnosis • Biopsy of infected tissue (skin, bone marrow) Multiple, tiny 2-5 um amastigotes within histiocytes  Distinct kinetoplast (bar-like structure adjacent to nucleus)  • PCR • Urinary antigens (visceral)  DDx of multiple tiny intracellular organisms • • • Leishmania – kinetoplast Histoplasma – budding Toxoplasma – somewhat curved, mostly extracellular
    56. 56. Leishmania donovani Skin lesion Sand Fly Kinetoplast next to nucleus
    57. 57. Babesia       Ixodes tick Protozoan: B. microti, B. divergens Zoonosis (deer, cattle, rodents; humans accidental host) Transmission by Ixodes tick bite Infects red blood cells Found world-wide B. microti along the Northeast US • Nantucket Island, Martha’s vineyard, Shelter Island  Malaria-like syndrome • Fever but without periodicity, “B-symptoms”, hemolytic anemia, hemoglobinuria, renal failure  Dx: • Blood smear examination   Ring form only (mimics P. falciparum) Tetrads (unlike P. falciparum) Maltese cross (tetrads)
    58. 58. Babesia
    59. 59. MALARIA Protozoan  Transmitted by the anopheles mosquito  Endemic to tropical areas 
    60. 60. Malaria Symptoms        Fever and chills Splenomegaly Headache Abdominal pain Diarrhea Myalgia Blackwater fever (hemolysis, hemoglobinuria, renal failure) – P falciparum only
    61. 61. Malaria Symptoms  Fever pattern Parasite Disease Plasmodium falciparum P. vivax Malignant tertian malaria Benign tertian malaria P. ovale Benign tertian malaria P. malariae Quartan malaria Tertian = q 48 hours (every other day) Quartan = q 72 hours
    62. 62. Malaria  Physical exam findings • • • Fever Splenomegaly P. falciparum Jaundice  Hepatomegaly  Increase in respiratory rate  CNS involvement    Diagnosis: peripheral blood smear (gold standard) Molecular tests are available but not yet widely used
    63. 63. Malaria  Distinction is between P. falciparum and non-falciparum • P. falciparum = rapidly progressive and LETHAL (malignant tertian fever), often chloroquine-resistant • Non-falciparum = rarely cause severe manifestations, often chloroquine sensitive  Relapsing malaria • Dormant hepatic phase  Hypnozoites of P. vivax and P. ovale
    64. 64. Two in the Liver/Two Not!!  Two types of malaria that don’t recur from the liver: • P. falciparum – high incidence and severity • P. malariae – lower incidence and severity  Two types of malaria that do recur from the liver: • P. vivax – high incidence, most of the world except Western Africa • P. ovale – lower incidence, occupies the niche in Western Africa
    65. 65. Life Cycle of Plasmodium Species MALARIA
    66. 66. RBC forms Merozoites Ring form  Trophozoite Schizont (ruptured schizont) Gametocyte
    67. 67. Plasmodium species Plasmodium  Plasmodium  Plasmodium  Plasmodium  falciparum vivax ovale malariae
    68. 68. P. falciparum P. vivax, P. ovale P. malariae Babesia Vector Mosquito Mosquito Mosquito Ixodes tick RBC Any RBC Young RBC; enlarged Mature RBC; Not enlarged Ring Multiple can be seen; delicate; “appliqué” Rarely >1; thickened Schizont Rarely seen Commonly seen Bananashaped Round none None None Present No Yes No Brown No 5-10% Gametocyte Extra-RBC form Schüffner dots Pigmentation Infection rate >2% <2% Protective polymorphism s Hemoglobin S, C,E, alpha and beta thal, G6PD Duffy negative (P. vivax) 1-12 Tetrads (Maltese cross) Delicate Rings only “rosette” none
    69. 69. Malarial Preparations Thick smear     Drop of blood on slide Water rinse to eliminate rbc’s Stain with Giemsa stain (not WrightGiemsa) with proper pH Concentrated to spot malaria parasites Thin smear     Feather edge smear For optimal morphology, stain with Giemsa (not Wright-Giemsa) stain with proper pH Speciation of malaria Parasitemia (%)
    70. 70. Malaria Diagnosis    Microscopy is most often used Antigen detection – EIA available Molecular methods
    71. 71. P. ovale
    72. 72. “Rosette” schizont
    73. 73. P. malariae
    74. 74. P. vivax Amoeboid ring form P.Vivax – benign tertian malaria (every 48 hours), Duffy negative RBC is protective Africans lack Duffy rbc antigen and this prevents rbc invasion. Untreated infections last several years; dormant in the liver for years Patients can survive years without treatment, but chronic infection can lead to brain, kidney and liver damage
    75. 75. P. falciparum
    76. 76. P. falciparum Malignant tertian malaria Black water fever
    77. 77. Plasmodium species
    78. 78. P. falciprium Vector Mosquito NonFalciparum Mosquito Babesia RBC All RBC Young RBC Ring 1-3 delicate Rarely >1 thickened Gametocyte Banana shaped round none Extra-RBC form None None Present Pigmentation Black brown none Infection rate >2% <2% 5-10% Protective polymorphis ms Hemoglobin S, Duffy negative C,E, alpha and beta thal, G-6PD Ixodes tick 1-12 Tetrads Delicate Rings only
    79. 79. Other Protozoa • Toxoplasma
    80. 80. Organism Toxoplasma gondii Transmission Oral from cat fecal material or meat Disease/Sympto ms Adult: flu like; congenital: abortion, neonatal blindness and neuropathies Diagnosis Intracellular (in macrophages) tachyzoites Treatment Sulphonamides , pyemethamine , possibly spiramycin (non-FDA)
    81. 81. Toxoplasma gondii      Coccidian protozoan House cat = definitive host Ingestion of infective oocysts from contaminated cat feces Ingestion of improperly cooked meat from animals that serve as intermediate hosts (rodents) Symptoms • Predilection for lung, heart, lymphoid organs, CNS/eye • Infectious mono-like; lymphadenitis, hepatitis, rash, encephalomyelitis, myocarditis, chorioretinitis • Transplacental infection   1st trimester  spontaneous abortion, stillbirth or severe disease 2nd/3rd trimester  CNS infections (epilepsy, encephalitis, intracranial calcifications, MR, chorioretinitis, blindness, hearing loss), jaundice, rash • AIDS - Encephalitis; mass lesions in brain
    82. 82. Toxoplasma gondii Strongly associated with young Kittens
    83. 83. Toxoplasma gondii  Diagnosis • Serology EIA Anti-toxo IgM – congenital and acute infection; may persist for months  Anti-toxo IgG – common; if positive, gestations safe from intrauterine toxoplasmosis infection  • PCR
    84. 84. Toxoplasma gondii Can be diagnosed by serology
    85. 85. Toxoplasma gondii  Toxoplasma gondii cyst in brain tissue stained with hematoxylin and eosin
    86. 86. Free-living Amoeba Naegleria fowleri  Acanthamoeba  Balamuthia 
    87. 87. Amoebic meningoencephalitis Most commonly caused by Naegleria fowleri  Granulomatous amoebic encephalitis or brain abscess(es) caused by Acanthamoeba and Balamuthia  Clinical scenario: swimming or diving in fresh-water pools 
    88. 88. Naegleria fowleri -Found in warm fresh water -Breath-in through nose-> brain Brain tissue with Naegleria fowleri trophozoite
    89. 89. Brain tissue with Naegleria fowleri trophozoites
    90. 90. Contact-lens keratitis Caused by Acanthamoeba  Can be cultured on a “lawn of E. coli”  • Take corneal scapings • Visible trail of ameba moving across plate ingesting E. coli
    91. 91. Acanthamoeba
    92. 92. HELMINTHS Nematodes (roundworms)  Trematodes (flukes)  Cestodes (tapeworms) 
    93. 93. Nematodes Enterobius  Ascaris  Trichuris  Necator and Ancylostoma (Hookworm)  Microfilaria – Wucheria, Brugia, Loa loa, Mansonella, and Onchocerca 
    94. 94. Enterobius vermicularis (pinworm)      Humans considered only host Females 8-13mm, males 2-5 mm Dwell in the cecum ¼-1/2 inch in thickness, white, lloks like string in stool Lay up to 15,000 eggs • Oval with a flattened side: 50-60um by 20-30um   Diagnosis- Scotch tape test or anal swab Most common helminth in US
    95. 95. Enterobius vermicularis (pinworm) eggs Asymmetrical eggs
    96. 96. Pinworm larvae
    97. 97. Ascaris lumbricoides (roundworm)  1-1.2 billion people infected • More common in children 20,000 death  Largest helminth to affect humans  Females 20-35cm long, males 1530cm with a curved tale  • Can cause intestinal obstruction
    98. 98. Ascaris lumbricoides
    99. 99. Ascaris eggs Unfertilized eggs-large & oval, mammillated layer is pronounced Fertilized eggs- smaller, rounder, mammillated layer is less obvious
    100. 100. Trichuris Trichiura (whipworm)       Soil transmitted Can be similar to amebiasis PVA preserved samples inferior to formalin Adults attach to large intestine and are rarely recovered Thinnest part- head Males are smaller than females
    101. 101. Trichuris trichiura
    102. 102. Necator americanus, Anclyostoma duodenale (Hookworms)    Soil transmitted 2nd most common helminth infection Enter via exposed skin Necator or Ancylostoma – Hookworm egg
    103. 103. Hookworm life cycle
    104. 104. Strongyloides stercoralis    Soil transmitted Larval form-does not have eggs or other forms It has internal structures Strongyloides larvae
    105. 105. Strongyloides stercoralis Can be found in intestines or stools In real sick can go to lung and cause pneumonia
    106. 106. Trichinella spiralis -Tissue nematode -All stages occur in single host -usually an incidental finding in muscle
    107. 107. Microfilariae  Sheathed • Wucheria bancrofti and Brugia malayi  Elephantiasis (lymphangitis/lymphedema) • Loa loa   Calabar swellings & migrating worms in the conjunctiva Not sheathed • Onchocerca volvulus • Mansonella species  Allergic skin reactions, edema, Calabar swellings
    108. 108. How to tell them apart  Are they sheathed? • Yes: Wucheria, Brugia, Loa loa • No: Onchocerca, Mansonella  How far do nuclei extend? • Terminal and subterminal nucleus: Brugia • To the end: Loa loa
    109. 109. Identification of microfilariae is based on the presence of a sheath covering the larvae, as well as the distribution of nuclei in the tail region A, W. bancrofti. B, B. malayi. C, L. loa. D, O. volvulus. E, Mansonella perstans. F, Mansonella streptocerca. G, Mansonella ozzardi.
    110. 110. Filaria Identification a. W. bancrofti • a. B. malayi • a. Sheathed, two small nuclei in tail O. volvulus • a. Sheathed, nuclei stop short of end of tail Unsheathed, from skin, not blood Loa loa • Sheathed, nuclei to continue to end of tail
    111. 111. Wucheria bancrofti
    112. 112. Wuchereria bancrofti Sheath
    113. 113. Brugia malayi
    114. 114. Brugia malayi
    115. 115. Loa loa
    116. 116. Loa loa (eye worm)
    117. 117. Mansonella perstans
    118. 118. Onchocerciasis Black fly
    119. 119. Onchocerciasis
    120. 120. Trematodes (Flatworms)  Intestinal and Liver flukes • Fasciolopsis buski • Fasciola hepatica  Liver flukes • Clonorchis sinensis (Chinese liver fluke)   Paragonimus westermani – oriental lung fluke Schistosomes • S mansoni – intestinal bilharziasis • S haematobium - urinary • S japonicum – blood fluke, found in intestines
    121. 121. Intestinal and liver flukes
    122. 122. Distinct nose Fasciola hepatica
    123. 123. Fasciolopsis buski Fasciola hepatica
    124. 124. Fasciolopsis buski Fasciolopsis buski
    125. 125. Clonorchis sinensis knobbin Shoulders operculates
    126. 126. Paragonimus westermani Transmission: Crab or crayfish Symptoms: chest pain, hemoptysis cough, pulmonary infiltrates, cerebral lesions Diagnosis: Eggs is sputum or feces Egg is operculate, unembryonated, thick shell, asymmetrical and large
    127. 127. Schistosoma mansonii Paragonimus westermani
    128. 128. Schistosoma mansoni Schistosoma haematobium Schistosoma jajonicum
    129. 129. Cestodes (Tapeworms) Flattened dorsoventrally, segmented Head with armed or unarmed scolex Proglottids immature, mature (sex organs) Gravid (with eggs) Internal structure of proglottids Hermaphroditic-ovary, testes, vitellaria, uterus, genital pore and ducts Lateral excretory and nervous system No gut-tegument absorbs nutrients Muscles-longitidinal and horizontal        Examples Diphyllobothrium latum Taenia saginata Taenia solium Hymenolepis nana Hymenolepis diminuta Echinococcus granulosis
    130. 130. Diphyllobothrium latum
    131. 131. Diphyllobothrium latum      Poorly-cooked fresh-water fish(salmon) Scandinavian, Russia, Canada, N. USA, Alaska Broad fish tapeworm Longitudinal sucker Eggs have non-shouldered operculum and knob • They are not embryonated  Causes Vit B12 deficiency
    132. 132. Diphyllobothrium latum
    133. 133. Sucking plate Diphyllobothrium latum
    134. 134. Taenia Species – two species Outstanding characteristics Taenia saginata Taenia Solium  Beef tapeworm  4 suckers on scolex  >13 uterine branches in proglottids Ingestion of cysticerci in beef Intestinal infestation Ingestion of eggs -> Non-human pathogen Pig tapeworm Ring of thorns/crown on scolex <13 uterine branches in proglottids Ingestion of cysticerci in pork Intestinal infestation Ingestion of eggs -> Cysticercosis
    135. 135. Taenia species
    136. 136. Taenia eggs Identical eggs for the two species
    137. 137. Taenia saginata Proglottid > 12 uterine branches
    138. 138. Taenia solium Scolex - Ring of thorns Proglottis – fewer uterine branches (<=12 uterine branches)
    139. 139. Cysticercosis Caused by the ingestion of T. solium eggs Not eating infected pork
    140. 140. Cysts of Cysticercosis
    141. 141. Hymenolepis nana
    142. 142. Larger outer shell No radial striations Hooklets inside Hymenolepis nana Most common cestode recovered in USA Worm is 2-4 cm Egg has inner & outer shell separated space Water /food contaminated by rodent droppings
    143. 143. Hymenolepis diminuta Uncommon tapeworm Big egg @ 80 microns in diameter
    144. 144. Echinococcus – hydatid cyst
    145. 145. Echinococcus – hydatid cyst Sand like material Contained in the cyst Short tapeworm
    146. 146. Tapeworms
    147. 147. Relative size of Helminth eggs
    148. 148. Insects of interest – not already mentioned
    149. 149. Maggots Bot fly larvae Extrudes from the skin
    150. 150. Ticks of importance Hard Ticks Soft tick Expands with blood engorgement
    151. 151. Hour glass On tummy Black Widow spider
    152. 152. Flea Hair nit Body Body louseLouse Crab louse
    153. 153. Mite Scabies Tiny eggs under skin