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91 Cards in this Set
- Front
- Back
Trypanasomatids
basic info |
- Asexual
- single flagella and kinetoplast - vector-borne - amastigote (intracellular) and trypomastigote in mammals - promastigote and epimastigot in vectors |
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Definitive host
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1° - host in which the parasite completes the sexual phase of its life cycle
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Filariae
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- Blood and tissue namatodes
- long, slender roundworms - may live 10-15 years and they release microfilariae which live in the blood or skin and are the infective stage for the insect intermediate host |
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Myiasis
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- Dipteran larvae
- Musca domesticus is faculative - Bed bugs (Cimex) are obligatory – many are bird ectoparasites – live in beds and feel painlessly at night – Not a vector |
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Enterobius vermicularis
Basic Info |
- intestinal nematodes transmitted by ingesting egg - Pinworm
- Female lives in large intestine and emerges through anus at night to lay sticky eggs on the perianal skin - extreme itching - children most susceptible but can spread to whole family |
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Kinetoplast
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- Within mito
- Minicircles or Maxicircles - Fcn was mystery - code for gibberish - produce correct mRNA for mito via RNA editing (insert U’s into specific sites) |
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Intermediate host
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2° - other host in which the parasite lives (completes a life-cycle phase, or reproduces asexually)
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Wuchereria bancrofti
Basic Info |
- elephantiasis or Lymphatic filariasis - gross swelling of limbs - lymphatic ducts blocked and scarred
- develops after years of chronic and repeated infection |
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Lice
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- Complete metamorphosis
- Mammalian lice are Anaplura (Pediculus humanus and pubis) - Flat, Suck blood - Head (hair shaft) and Body (clothing seams) identical but do not interbreed - treat w/ pyrethrins, Kwell® - Adults can survive off host for ~ 10 days, nits can last much longer |
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Enterobius vermicularis
Diagnosis and Treatment |
- Scotch tape prep to the perianal skin at night then placed on slide - look for eggs w/ moving larvae inside
- may occasionally be seen on the surface of the stool - treat entire family and launder all beding and PJs |
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Trypanasomatids rhodesiense
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- East Africa
- wild animal reservoir – Glossina morsitans group, lives in savanna – accute - months to develop |
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Malaria
Vectors and Stages in humans |
- Vector is definitive host - female mosquitoes of the genus Anopheles bite at night ~1 AM
- Stages in humans i. Pre-erythrocytic stages (merozoite, trophozoite, schizont) ii. Erythrocytic asexual stages (merozoite, ring, trophozoite, schizont) iii. Erythrocytic sexual stages (gametocytes) iv. Hypnozoite |
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Wuchereria bancrofti
Infection |
- Adult worms live in lymphatics and microfilariae in blood are ingested by the mosquito
- mature in mosquito and microfilariae can be transmitted - do nocturnal periodicity, where they circulate at night, when vector is active, and remain in lung caps in day - Travelers may have rapid progression and tropical pulmonary eosinophilia w/ with symptoms but no microfilaremia - prevent w/ mosquito abatement and early treatment |
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Lice vectors
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- Epidemic typhus - Rickettsia prowazecki
- Relapsing fever - Borrelia recurrentis - Trench fever - Rickettsia quintana |
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Ascaris lumbricoides
Basic Info |
- intestinal nematodes transmitted by ingesting egg
- roundworm - live in the SI - female produces 200,000 eggs a day -> feces - eggs need 2 wks in warm moist soil to embryonate and be infective - so you get it from no plumbing or feces in soil |
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Trypanasomatids gambiense
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- West Africa
- human reservoir – Glossina palpalis group, lives by rivers – chronic - years to develop |
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Malaria
Clinical course |
- Prepatent period - asymptomatic while parasite multiplies in liver
- Paroxysm - shaking chills, then high fever when infected RBC burst to release new merozoites - May be periodic (48 or 72 hours) |
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Wuchereria bancrofti
Disease |
- chronic, cumulative disease w/ few symptoms at first
- damage from inflam which varies among individuals - microfilariae can be detected in blood at night when asymptomatic - After 8 to 16 months, painful lymphangitis, esp in groin w/ recurring fever - Also eosinophilia - can lead to swelling of limbs, complete blockage - if elephantiasis no circulating microfilariae |
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Siphonaptera
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- Fleas on warm blooded
- Complete metamorphosis - legs for jumping w/ contains resilin (elastin protein) and hooks to catch fur - eggs fall off host, mature then nest - unfed flea can survive <3 years in high humidity |
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Ascaris lumbricoides
Infection |
- eggs ingested and hatch in
duodenum - penetrate mucosa and migrate to lungs via blood - do 2 molts in lungs and cause symptoms of pneumonitis w/ eosinophilia - Mature larvae penetrate alveoli - coughed up and swallowed - in 9 weeks, they mature into adults - can live 2 years |
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African Trypanasomatids
disease and treatment |
- trypomatigote in human, epimastigot in vector
- Primary –lymphadenopathy (Winterbottom’s sign) - Secondary –systemic disease (fever, wasting) - Advanced – CNS disease (lethargy, insomnia, seizures) - Ag variation of Surface Glycoprotein for protective coat - >1000 VSG genes - No vaccine - Old drugs toxic (Suramin, Pentamidine, Melarsoprol) - New drugs (Eflornithine, DB 289) |
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Malaria
Diagnosis |
- Giemsa - stained blood smears thick smear thin smear Rapid tests
- Travel history - “autochthonous” malaria |
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Onchocerca volvulus
Basic Info |
- tissue nematode, liver blindness
- Adults live in nodules under the skin, make microfilariae that migrate in skin - micros transmitted by bite of black fly that cant fly far from fast-flowing water - tropical Africa, S America |
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flea vectors
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- Plague - Yersinia pestis is zoonosis in rodents - Bubonic w/ buboes (swollen lymph nodes)or Pneumonic from coughing - the bacillus causes proventricular blockage -> regurgitation of bacilli
- Endemic typhus - Rickettsia typhi (mooseri) |
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Ascaris lumbricoides
Symptoms |
- depends on # of eggs ingested (worms dont multiply in pt)
- may produce abdominal discomfort or obstruction - Adults must move to stay in place - enter small openings like bile duct or nose - fever or drugs can promote migration - Diagnose via fecal specimen |
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Onchocerca volvulus
Infection |
- Micro migrating in skin ->
intense itching -> 2o inf - months to years, then skin degeneration (pachydermia) - may get eye -> blindness |
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Plasmodium vivax
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- invade reticulocytes and live in enlarged red cells -> Schuffner’s dots
- latent forms (hypnozoites) remain dormant in liver for months then re-initiate parasitemia - 48 hour periodicity |
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Trypanosoma cruzi
basic info |
- Chagas’ Disease
- Amastigote in human, Epimastigote in vector - in america, spread by tratomes (bugs), tranfusions or rodents |
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Chelicerata
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mites and ticks
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Necator americanus
Basic Info |
- Hookworm
- Intestinal nematodes transmitted via skin penetration - live in the SI w/ teeth to bite into mucosa - use blood for nutrients and O2 - change attachment sites often - blood loss is major effect |
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Onchocerca volvulus
Diagnosis and Treatment |
- taking superficial skin
snips, place in water, and examine for motile micros - If nodules, biopsy or nodulectomy - control w/ Ivermectin |
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Plasmodium ovale
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- invade reticulocytes and live in enlarged red cells -> Schuffner’s dots
- latent forms (hypnozoites) remain dormant in liver for months then re-initiate parasitemia - 48 hour periodicity |
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Trypanosoma cruzi
disease |
- probably autoimmune response, but possibly direct effect
- Acute disease has Romano’s sign, parasitemia, febrile illness, trypomastigotes in blood - Chronic disease occurs 10-20 years later w/ chronic cardiomyopathy, mega-colon and esophagus |
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Argasids
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- soft ticks, can't see head
– nocturnal feeders, only stay on host for a few minutes – bird ticks |
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Ancylostoma duodenale
Basic Info |
- Hookworm
- Intestinal nematodes transmitted via skin penetration - live in the SI w/ teeth to bite into mucosa - use blood for nutrients and O2 - change attachment sites often - blood loss is major effect |
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Taenia saginata
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- Cestodes or tapeworms
- adults live in human GI - eggs from feces may be ingested by cow, hatch in their intestine and migrate to muscle to form cysticerci (larval tapeworm in fluid sac - ingest undercooked meat and cysticercus elongates into adult w/ segments - Eggs form in post proglottids, detach, then passed w/ feces |
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Plasmodium malariae
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- no hypnozoites but may persist in bloodstream (low levels)
- 72 hour periodicity |
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Trypanosoma cruzi
diagnosis and treatment |
- Parasites not in peripheral blood
– diagnose w/ Xenodiagnosis (old), Immunological, IFA or Enzyme immuno assay (EIA) - treat accute w/ nifurtimox (lampit) |
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Ixodidae
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- hard ticks, can see head
- Not host specific, but have preferences - Female lays eggs then dies - Gene's organ applies wax, then Larva absorbs water, find host, feeds then drop off - it then Molts to nymph, finds, feeds drops off - Molts to adult, finds new host, mates, engorges and drops off |
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Necator americanus
Infection |
- Eggs in feces hatch in warm sandy soil - the larvae eat bacteria -> infective (3rd) stage in a week
- penetrate barefeet and cause ground itch - travel via the blood to lungs - penetrate alveoli, coughed up, then swallowed - mature to adults in SI in 4 to 7 wks |
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Taenia solium
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- Cestodes or tapeworms
- adults live in human GI - eggs from feces may be ingested by pig, hatch in their intestine and migrate to muscle to form cysticerci (larval tapeworm in fluid sac - ingest undercooked meat and cysticercus elongates into adult w/ segments - Eggs form in post proglottids, detach, then passed w/ feces - can cause cysticercosis in humans - in muscles its ok, in brain heart lungs eye its not - human to human transmission also possible |
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Plasmodium falciparum
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- invade red cells of all ages
- the sickle-shaped gametocyte - 48 hour periodicity |
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Leishmaniasis
Basic info |
- Amastigote (in phagolysosome until ruptire) in human, promastigote in vector
- can cause visceral or Cutaneous / Mucocutaneous leishmaniasis - mainly epizootic |
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Ticks
How they operate |
- Find host by sensing ground vibrations and climb to tops of vegetation via Haller's organ on front legs and responding to odors, T and CO2
- Haller’s organs finds spot to bite into - Chelicerae sense ATP and pierce skin - phenols secreted by adult males helps mating |
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Ancylostoma duodenale
Infection |
- Eggs in feces hatch in warm sandy soil - the larvae eat bacteria -> infective (3rd) stage in a week
- penetrate barefeet and cause ground itch - travel via the blood to lungs - penetrate alveoli, coughed up, then swallowed - mature to adults in SI in 4 to 7 wks |
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Tapeworms
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- rarly cause symptoms
- no gut or digestive enzymes - absorb nutrients from host - may be noticed if a proglottid is passed in the feces - Diagnosis w/ feces for eggs and if proglottid, inject uterus with India ink to show the uterine branches (fewer in solium) - The scolex (“head”) of solium has armed rostellum (circle of hooks) in addition to the four suckers |
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Falciparum malaria
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- Most common, dangerous, and drug-resistant
- no intermediate stages seen in periphery - secrete proteins that form “knobs” on RBC surface which cytoadhere to capillaries and are “sequestered” - can block circulation in the brain |
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Leishmaniasis
Clinical picture |
- Initially painless skin lesion, and most disappear spontaneously
- May metastasize to liver, spleen, bone marrow (visceral l's) or MM / skin - mainly in poorly nourished children - high death rate if untreated |
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Tick
Vectors |
- Rickettsia
- Ehrlichiosis - Lyme disease - white-food mouse and white-tailed deer - Babesiosis - Ixodid ticks - East Coast Fever - Borrelia duttoni - Coxiella burnetti - Congo-Crimean Hemorrhagic fever |
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Necator americanus
Diagnosisa and treatment |
- diagnose via eggs in stool
- prevent w/ sanitary sewage disposal, shoes, and treating infected |
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Ancylostoma duodenale
Diagnosis and Treatment |
- diagnose via eggs in stool
- prevent w/ sanitary sewage disposal, shoes, and treating infected |
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Leishmaniasis
Epidemiology |
For visceral
- Endemic from animal reservoirs (dogs, other) - Epidemic from human-fly-human transmission, esp in India and Sudan - Opportunistic in AIDS in S. Europe and Brazil |
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Cysticercosis
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- severe tapeworm disease
- can cause seizures, even w/out an adult tapeworm - symptoms may appear long after exposure to the eggs - diagnose w/ Abs in the blood or CSF - cysticerci are seldom found, but in muscle there are calcium deposits - pork tapeworm most common in Mexico, Chile, E Europe, S Africa, China, and Indonesia - Control by sanitary sewage, thorough cooking & inspection |
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Malaria
Prophylaxis |
- Chloroquine (only in very few geographic areas)
- Lariam (weekly, neuropsychological adverse effects) - Malarone (expensive, daily) - Doxycycline (photosensitivity, daily) - Primaquine (after exposure to P. vivax) - Personal physical protection |
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Mites
basic info |
- Lifecycle is Egg, larva, 2-3 nymph stages, adult
- Breate via trachea branching – cutaneous in small "Astigmata” |
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Strongyloides stercoralis
Basic info |
- Intestinal nematodes transmitted via skin penetration
- like hookworm, but eggs hatch in intestine and motile larvae passed in feces |
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Leishmaniasis
Diagnosis and Treatment |
- Diagnose w/ culture, Leishmanin, PCR, Serology, ELISA, DAT, Immunohistochem
- Treat w/ Antimonials like pentostam, glucantine for long course (28-40 daily!) – can also use Pentamidine or Amphotericin B (liposome) |
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trematodes
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- flukes - flatworms
- live in GI, bile ducts, lungs, BVs - complicated life cycles - asexual in snail and sexual in humans |
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Malaria
genetic resistant |
- Sickle cell trait
- Thalassemia - Glucose-6-phosphate dehydrogenase deficiency - Ovalocytosis - Duffy blood group negative |
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Sarcoptes scabei
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- adult is 250 µM long
- causes scabies in humans and "mange" in animals |
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Strongyloides stercoralis
Infection |
- In soil, rhabditiform larvae molt into infective filariform
larvae thaat get skin - can molt on skin or SI -> auto-reinfection - can persist for 50 yrs - asymptomatic or occasional larva currens (itching) from migrating larvae - - in immunosuppressed, can have hyperinfection - transplants are screened for Ab to it and are treated for it before receiving immunosuppressive drugs |
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Trichomonas vaginalis
Basic Info |
- anaerobic but no cyst
- Most common STD - Diagnosis w/ wet smear • Women: Yellowish vaginal discharge (most common, mimics yeast), itching and burning • Men: usually no symptoms; may cause non-gonococcal urethritis |
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Schistosomes
Basic info |
- bloodfluke (trematodes)
- mansoni cuases intestinal infection - in Africa, South America, and Caribbean - japonicum causes intestinal infection - in Far East - hematobium causes urinary infections in Africa |
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Babesiosis
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- mild illness
- Endemic in parts of US - May be mistaken for malaria - intra-erythrocytic - Tick-borne - Ixodesscapularis - Reservoir – white-footed mouse |
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Dust mites
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- D. pteronyssinus
- D. farinae - Euroglyphus maynei - in every household, prefer humid air |
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Cutaneous larva migrans
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- when hookworm larvae of dog enter's human skin
- produce migrating inflam rxn w/ creeping eruption - Similar symptoms w/ bird schistosomes |
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Trichomonas vaginalis
Patogensis |
- Lives in vaginal epi if pH high, often w/ yeast and bacterial overgrowths
- cysteine proteases, adhesins and hydrogenosome for virulence - hydroendosem reduces protons (H+) to H2 gas instead of reducing O2 to H2O - makes Metronidazole which generates free radicals |
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Schistosomes
Infection |
- live 10 yrs, male and female permanently coupled in veins of the GI or bladder - pass lots of spined eggs -> tissue damage and symptoms
- eggs get into the feces or urine and hatch to release a motile miracidium when released - must infect correct snail - make free-swimming cercariae than can penetrate human skin causin swimmer’s itch - developing larvae migrate via lymphatics and lungs to the venules and grow to adults |
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Toxoplasma gondii
Basic Info |
- feline is definitive host
- mammals intermediate host - can survive in M's by preventing lysosome fusion - also gets fibro and GI epi |
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Mite vectors
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- Scrub typhus - (Rickettsia tsutsugamushi)
- Rickettsial pox (Rickettsia akari) |
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Visceral larva migrans
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- when kids ingest soil w/ dog or cat roundworm, Toxocara canis or cati
- cant mature in humans, so it migrates to the liver - Symptoms rare - sometimes migrate to eye and cause retinal lesions, or to the brain and cause seizures |
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Trichomonas vaginalis
Clinical Presentation |
- Women have yellow discharge, itching and burning
- Men no symptoms, maybe urethritis |
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Schistosomes
Disease |
- mainly in rural areas where sewage enters water (snail can meet poop)
- Light infections may be asymptomatic after swimmer’s itch - sometimes fever - heavy infection -> granulomatous rxn and fibrosis - w/ mansoni, periportal fibrosis in the liver -> portal hypertension - may have distension of esophagus veins - w/ hematobium, obstruction of the ureters and 2o UTI, granulomas in the bladder, or bladder carcinoma. |
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Toxoplasma gondii
Epidemiology |
- big in developing countries and france
- infection via Oocyst from cat feces or Cyst (bradyzoites) from undercooked meat |
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DDT/Pyrethrins
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- D used to delouse soldiers in WWII
- P from flowers, later on synthetic (permethrin and deltamethrin) - Target Na+ channel to slow down nerve conduction |
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Schistosomes
Diagnosis and Treatment |
- detecting eggs in the feces or urine
- If found early and the patient, the chronic stages are avoided - Control via sanitation, look out for snails in waterways, treat infected persons |
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Entamoeba histolytica
disease stages |
- Amebiasis
- Trophozoite - pathogenic stage, single nucleus with a central nucleolus - Cyst - infective phase - survive in environment - has one to four nuclei |
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Toxoplasma gondii
Disease |
- accute is like mono
- Congenital -> malformations or occular disease in 1st tri, abortions in 2 and 3 - in AIDS, latent infection can cause fatal encephalitis, and retinal lesions |
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Organophosporous and Carbamates
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- nerve poisons
- Target ACh esterase - bind to serine, prevent recycling of Ach in synapse |
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Bacillus thuringensis
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- subspecies israelensis
- produces 5 toxin proteins in sporulation -> lysis of larval midgut cells. - dried larvae donuts slowly release organisms which are ingested by mosquito larvae - Resistance easy |
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Entamoeba histolytica
Pathogenesis |
- luminal if noninvasive
- hepatic if invasive - an abscess in the liver leads to fever and pain - it can rupture, metatstsize and is hard to diagnose |
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Toxoplasma gondii
Diagnosis and Treatment |
- Serology
- Culture/inoculation of mice - Antifolates (Pyrimethamine/sulfadiazine) - Atovaquone |
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Entamoeba histolytica
diagnosis |
- For intestinal disease, direct examination of stool, can confuse w/ E. dispar - need 3 specimens, good if from sigmoid - can use EIA too
- for liver abscess, use Serology, Aspiration (in abscess wall) |
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Cryptosporidium
Basic info |
- cattle pathogen
- First seen in humans in 1976 - common in AIDS patients - mild diarrhea in normal, sever if immunosuppressed - No effective treatment |
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Giardia lamblia
basic info |
- Trophozoites have 4 pairs of flagella and two nuclei, adhesive disc, lectins
– noninvaseive, gets small intestine - Cysts - four nuclei - No mito or hydrogenosome |
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Cryptosporidium
Transmission |
- Cysts are chlorine-resistant!!!!
- Transmitted via water and food - Outbreaks (>100 in US) - from Day-care, water supplies - big on in Milwaukee |
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Giardia lamblia
Epi |
- Most common GI parasite, esp children, often asymptomatic
- via water or person - cysts highly infectious, resistant to chlorine, and viable for months in water - Reservoir - beaver for sure |
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Cryptosporidium hominis
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- Humans only, main cause of outbreaks
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Giardia lamblia
Pathology |
- Acute form shows lots of trophs in stool w/ diarrhea, nausea, flatulence, weight loss
- In Chronic it's hard to find cysts - repeat ova and parasite exam (O&P) 3 times and may have to do duodenal aspiration - causes bad absorption of B12 & A, Iron, fat, sugar -> bad development in children - Human breast milk kills |
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Cryptosporidium parvum
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- humans in cattle, main cuase of sporatic cases
- the main one in developing countries |
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Cyclospora
Basic Info |
- like Cryptosporidium but bigger
- No animal reservoir - Outbreaks from Guatemalan raspberries - Treatment - Bactrim |