Card Set Information

2014-11-15 17:36:29
parasitology parasites fdn3 foundations tubberly

Some of the most disgusting infections imaginable
Show Answers:

  1. Amebiasis
    • entamoeba histolytica
    • amoebae or rhizopods
    • intestinal protozoa
    • most primitive
    • binary fission
    • moves by psuedopodia
    • fecal-oral of cysts that become trophozoites then cysts again
    • trophozoites multiply in intestines
    • humans are only resevoir
    • 90% are asymptomatic cyst passers
    • others are symptomatic with anchovy paste material and can develop acute rectocolitis (dysentery)
    • mainly outside of US, infecting 10% of the world
    • day care can contribute
    • rarely causes toxic megacolon, acute amebic appendicitis, extraintestinal amebiasis (liver, brain, pericardium, lung, skin, eye abscesses)
    • diagnose by stool examination for cysts or trophozoites
    • imaging study where you stain for amoeba and look at liver
  2. Giardiasis
    • giardia lamblia
    • flagellates
    • intestinal protozoa
    • fecal-oral cysts that become trophozoites then cysts again
    • trophozoites multiply in intestines
    • humans and beaver resevoirs
    • outdoorsy people infected in isolated cases
    • outbreaks when water supply contaminated or person to person in day care
    • bloating, gas, diarrhea due to villous atrophy causing malabsorption, epigastric pain
    • diagnose by stool examination for cysts or trophozoites that look back at you
  3. African sleeping sickness
    • trypanosoma brucei
    • flagellates
    • blood and tissue protozoa
    • tsetse fly vector
    • epidemic in regions of civil war and unrest in Africa
    • parasites divide inside the blood
    • clinical manifestation from high parasitemia (almost as high as RBC density)
    • peaks and trough wave function due to completely changing amino acid sequence every time immune system has almost won
    • VSG switching by gene conversion (telomeric VSG, chromosome-internal VSG, telomere exchange) and expression site switching
    • doesn’t need its mitochondria because it eats things in blood including sugar, causing hypoglycemia
    • east african sleeping sickness is acute fever, headache, occipital lymphadneopathy (Winterbottom’s sign)
    • West African sleeping sickness is subacute, chronic meningoencephalitis, subtle personality changes, somnolence to coma to death
    • causes nagana in cattle (so you can’t raise live stock in regions of Africa)
    • diagnose by identification of trypomastigotes in blood smear
    • no vaccine because of gene switching and tsetse fly
  4. Chagas’ Disease
    • trypanosoma cruzi
    • flagellates
    • blood and tissue protozoa
    • vector is reduviid bug or kissing bug, poop from blood meal
    • mainly in Latin America
    • often assymptomatic so issue with blood donation
    • they like heart muscle and with enough build up, cells lyse and release parasite into blood and reduviid bug can get some
    • acute phase with high parasitemia, periorbital edema, fever, anorexia, hepatomegaly and lymphadenopathy, death in some infants (due to fatal arrhythmia)
    • chronic phase with undetectable parasitemia, cardiomyopathy (thinning can cause legume leading to blood clotting), megasophagus/megacolon from shut down of innervation of smooth muscle
    • diagnose xenologically by letting non-infected bug feed on person and then squish and look for the bug
    • or serologically with PCR
  5. Leishmaniasis
    • flagellates
    • blood and tissue protozoa
    • 3 diseases caused by different Leishmania spp.
    • parasites love the macrophages and monocytes
    • cutaneous causes chronic, non healing ulcer with necrosis in the middle
    • visceral with parasites in macrophages of reticuloendethelial causing enlarged viscera, hepato and splenomegaly
    • mucocutaneous mutilates cartilage (degrades the nose)
    • diagnose cutaneous with a skin biopsy or serologic testing
    • money put forth by Gates foundation and friends
  6. Trichomoniasis
    • trichomonas vaginalis
    • flagellates
    • blood and tissue protozoa
    • most common in the world and in this country
    • only has trophozite stage
    • sexual transmission
    • vaginitis, prostatitis, urethritis
    • diagnose by trophozyte detection in the vaginal discharge or urethral exudate
  7. Malaria basics
    • plasmodium spp.
    • obligate intracellular
    • sporozoans
    • blood and tissue protozoa
    • vector is mosquito
    • DDT spraying has eliminated them from the US
  8. Malaria epidemiology
    • major killer of mankind, 3% infected
    • latin america, africa, asia
    • congo and nigeria are 40% of cases
    • 90% of death in subsaharan
    • primates only resevoir
    • comorbidities with HIV (therapies may cause overlapping toxicities)
    • comorbidities with poverty and malnutrition
  9. Plasmodium spp. differentiation
    • Plasmodium falciparum is malignant high parasitemia with CNS disease, 2 day schizont maturation, broad range of RBCs (thus malignancy), relapse period is months, 500k/mm3 peak parasitemia
    • Plasmodium vivax has latent course, 2 day schizont maturation, reticulocytes (immature), relapse period is years, 20k/mm3 peak parasitemia, outside of africa
    • Plasmodium ovale has latent course, 2 day schizont maturation, reticulocytes (immature), relapse period is years, 9k/mm3 peak parasitemia
    • Plasmodium malariae is persistent but on the out and out, 3 day schizont maturation, older RBCs, relapse period is decades, 6k/mm3 peak parasitemia
    • Plasmodium knowlesi is new, has primate transmission, severe, 1 day schizont maturation, relapse period is months, 300k/mm3 peak parasitemia, SE asia, quinolones work
  10. Plasmodium spp. lifecycle
    • mosquito bite sporozoites to blood to liver “Kupffer cell” (macrophages) binding and entering by thrombospondin receptor and properdin receptor
    • mature to merozoites and multiply 1-2 weeks
    • merosomes bud to capillary to RBCs
    • RBC 1-3 day lytic cycle with merozoite to trophozoite to schizont to lysis
    • some preschizonts in Kupffer are hypnozoites, dormant, espcially in malariae then in vivax and ovale (but all can)
  11. Malaria pathology
    • merozoites bind to surface lectins of RBC, using sialic acid to enter or other pathways depending on immune response
    • once inside RBC transcriptional control causes expression of new sticky surface proteins
    • plugs up vessels and less circulation means hard to clear (not traveling to spleen/liver)
    • causes capillary occlusion, splenomegaly and thrombocytopenia
    • brain occlusion is bad (esp. falciparum)
    • splenomegally and fibrosis can cause splenic rupture
    • var gene codes different antigens to evade immune
    • plasmodium eats hemoglobin
    • anemia
    • lysis releases toxic products triggering cytokines, which supresses RBC production and stimulates NO causing organ failure
    • inflammation promotes diffuse coagulation and capillary leak syndrome
    • liver overwhelmed with debris becomes dysfunctional (metabolic and synthetic impairment)
    • hypoglycemia, lactic acidosis, hyponatremia
    • free hemoglobin and occlusion injures renal tubules
    • fever, seizing, staring, weak, pale conjuctivae
  12. Malaria diagnosis
    • infected erythrocytes in thick and thin Giemsa stained blood smears
    • speciation by parasite appearance and RBC appearance
    • or PCR diagnosis with speciation and with resistance pattern determination
  13. Malarial resistance
    • things causing premature lysis
    • hemoglobin difficult to digest
    • different RBC antigen mutations
  14. Malaria therapy
    • classic is quinolones (chloroquine, mefloquine, primaquine) diffuse into vacuole, acidifies and lysis RBC prematurely
    • Antifols and sulfas (pyrimethamine, trimethoprim) inhibit folate synthesis, impairing DNA/RNA
    • artemisinins, chinese tradition wormwood (worldwide plant) mechanism unknown but probably through iron-oxo radical formation
    • usually artemisinin-base combination therpaies (ACTs) because we don’t want artemisinin resistance to develop
    • can use antibiotics like tetracycline, doxycycline, clindamycin
    • preventative through netting, clothing, spraying, water/waste infrastructure
    • prophylactic antibiotics
  15. Schistosomiasis
    • trematode
    • blood fluke aka flatworm
    • 3 schistosoma spp
    • 250,000,000 infected annually with 1,000,000 deaths per annum
    • long slender female spends life in copula in male gynecophoral canal
    • self coat with antigens so that we don’t attack
    • 1000s of eggs per day, half are for research half them are expelled by urine and feces
    • round or oval eggs with appendiges
    • requires repeat exposure
    • cercarial dermatitis from cercariae that didn’t completely penetrate
    • Katayama fever 4-6 weeks after pimary heavy infection, release of egg-antigen or antigen-antiegen complexes, hives, swelling, arthritits, fever, lasts weeks, significant mortality
    • chronic schistosomiasis, main thing is engorgement of adbomen, with T cell mediates resopnse and fibrosis of hepatic blood flow in and out impinges. polyps get lodged in intestine. Also granulomas form and can impinge upon the bladder causing pyelonephritis, dysuria, hematuria, chronic bacteremia, renal failure, baldder cancer. Lastly, pulmonary fibrosis, central nervous system involvement (seizures or transverse myelitis)
    • diagnose by looking at eggs in feces or urine
  16. Beef tapeworm infection
    • taenia saginata
    • intestinal tapeworm
    • worldwide distribution
    • human is only definitive host, cow is intermediate
    • oral fecal (human) oral through intestinal wall to muscle (cow)
    • matures in human intestine and cow muscle, larva cysts
    • dull, colicky abdominal pain (mild symptoms)
    • diagnosed by eggs/proglottids in feces
    • eggs indistinguishable from T solium, but proglottids differ
    • undercooked meat
  17. Pork tapeworm infection
    • taenia solium
    • intestinal tapeworm
    • Latin america, africa asia
    • human can be definitive and intermediate host, pig is intermediate
    • oral fecal or premature hatching (human) oral through intestinal wall to muscle (pig)
    • larva cysts mature in various tissues especially brain and striated muscle
    • dull, colicky abdominal pain (mild symptoms)
    • cystercercosis CNS disease, seizures, ocular disease, hydrocephalus (ventricular cysts)
    • diagnosed by eggs/proflottids in feces
    • eggs indistinguishable from T saginata, but proglottids differ
    • undercooked meat
  18. Echinococciasis
    • extraintestinal tapeworm
    • Echinococcus granulosus causes cystic hydatid disease
    • more rare is alveolar hydatid disease caused by Echinococcus multilocularis
    • human, sheep, goats, pigs are intermediate, canine is definitive
    • oral fecal in dogs and oral through intestinal wall to liver lungs etc in intermediate
    • cyst ruptures may cause anaphylactic reaction
    • diagnosis by xray/CT cysts
  19. Pinworm infection
    • enterobius vermicularis
    • intestinal nematode
    • oral fecal
    • hatch in small intestine female to cecum, gravid female to perianum, egg to environment
    • world wide, most common helminth
    • no symptoms maybe pruritus ani
    • scotch tape test
    • classic flat sided egg
    • mostly children
  20. Whipworm infection
    • trichuris trichiura
    • intestinal nematode
    • hatch, develop into adults in distal colon, eggs produced and excreted, eggs mature in soil>10 days
    • latin america, asia, africa
    • oral fecal, mostly young children
    • rootbeer eggs and fat tail
    • no symptoms
    • heavy infection causes malnutrition, rectal prolapse when bearing down (childbirth), inflammatory diarrhea
    • diagnosed by eggs in feces
  21. Large roundworm infection
    • Ascaris lumbricoides
    • intestinal nematode
    • larva penetrate intestine, lung, up down, small intestine produce eggs (20k/worm/day), eggs excreted, mature in soil 2 weeks
    • oral fecal
    • largest intestinal nematode
    • tropics, subtropics
    • poopy veggies
    • no symptoms except when in lung
    • cough, fever, dyspnea, eosinophilia (Löeffler’s syndrome)
    • heavy infections have malnutrition
    • knock them out with narcotic, they let go and are passed
    • diagnosed by eggs in feces or eosinophilia during tissue phases
  22. Hookworm infection
    • Ancylostoma duodenale (old world) or necator americanus (new world) (indistinguishable eggs)
    • intestinal nematode
    • skin penetration, to lung up and down, lay eggs in small intestine (200k/worm/day), excrete eggs, rhapditiform larvae hatch and molt
    • rhabditiform (rod like) are feeding form
    • filariform (thread like) nonfeeding
    • tropical subtropical for duodenale and 500 million infections per year
    • SE US, latin america, indonesia, philippines for americanus
    • itching, dermatitis at penetration site, no other symptoms
    • heavy infection malnutrition and anemia (.2 ml/worm/day blood consumption)
    • diagnosed by eggs in feces
  23. Strongyloidiasis
    • filariform penetrate skin, to lung up and down, lay eggs, rhabditiform in feces, can autoinfect, excreted and free living adult lay eggs, hatch
    • males are not parasitic and females are parthenogenetic
    • worldwide, warmer climates
    • humans only definitive host
    • larva currens, migratory pneumonitis
    • meningitis, pneumonia in immunocompromised except AIDS (weird)
    • diagnosed by larvae in feces
  24. Elephantitis
    • Wuchereria bancrofti or Brugia malayi
    • Filarial worm
    • nocturnal or diurnal microfilariae
    • adults in lymph vessels/nodes
    • elephantitis by lymphatic obstruction
    • bancrofti is inguinal, epitrochlear, axilary or tropical pulmonary eosinophilia (also chronic)
    • accute of bancrofti are filarial fever (microfilariae), filarial adenolyphangitis, orchitis
    • malayan (from malayi) more in extremities (lower especially) less often genital
    • surgery or oil massage, yoga, compression, antifungal drugs
    • diagnosed by microfilariae in blood
  25. Loiasis
    • Loa loa
    • filarial worm
    • adults in subcutaneous and conjunctivae
    • calabar swellings are subcutaneous edemas up to several centimeters, rapid onset, lasting few days, pruritus and urticaria (hives) and fever
    • diagnosed by microfilariae in blood
  26. River blindness
    • Onchocerca volvulus
    • filarial worm
    • africa
    • adults in subcutaneous nodules, microfilariae in skin
    • subcutaneous nodules, dermatitis, regional lymphedema
    • microfilariae trapped in eye harbor Wolbachia bacteria and immune response causes ocular inflammation and blindness
    • diagnosed by skin nodule biopsy
  27. Trichinosis
    • Trichinella spiralis
    • nematode whose larvae cause pathology in human tissue
    • meat ingested cyst, adult in small intestine mate, larvae form cysts in striated muscle
    • pigs (wild and domestic) and wild mammals
    • orbital edema, muscle pain, respiratory distress, headache, weakness, myocardial and CNS involvement
    • <10 larvae/gram is subclinical
    • 50-500 moderate symtpoms
    • >1000 severe symptoms
    • diagnosed clinically with history of undercooked meat, serologic tests are useful, larvae in muscle biopsy
  28. Cutaneous larva migrans
    • Ancylostoma brazailiense
    • cat and dog hookworm
    • direct through skin
    • creeping eruption (traces larva)
    • parasites persist weeks to months
    • diagnosed by larva in skin
  29. Toxoplasmosis
    • Toxoplasma gondii (sporozoan related to malaria)
    • cat is definitive host, mammals and birds are intermediate
    • oral fecal or meat consumption for definitive and meat consumption or fecal oral for intermediate
    • 30% of world infected (20% in US), animals widely infected
    • risky behavior
    • mild flu like, ocular problems, self limited
    • immunocompromised encephalitis, pneumonitis
    • 1 in 500 pregnant women acquire acute toxoplasmosis (naive mother) and is a TORCH causing abortion, mental retardation, blindness, hydrocephalus, intracranial calcification
    • tissue cysts contain thousands of bradyzoites, hard to kill even with cooking and hidden from immune system
    • tachyzoites are fast growing and lytic, easy to kill
    • accute infection almost never diagnosed but by tachyzoite identification in biopsy, PCR from blood or tissue, radiology of brain, IgG or IgM widely used but hard to interpret without baseline knowledge
    • chronic infection diagnosed by serology, cysts in biopsy
    • treatment is super effective by antibiotics
    • prevention by washing wild game, meats, vegetables, avoid cat feces