Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/91

Click to flip

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
Definitive host
1° - host in which the parasite completes the sexual phase of its life cycle
Filariae
- 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
Myiasis
- 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
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
Kinetoplast
- 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)
Intermediate host
2° - other host in which the parasite lives (completes a life-cycle phase, or reproduces asexually)
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
Lice
- 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
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
Trypanasomatids rhodesiense
- East Africa
- wild animal reservoir
– Glossina morsitans group, lives in savanna
– accute - months to develop
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
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
Lice vectors
- Epidemic typhus - Rickettsia prowazecki
- Relapsing fever - Borrelia recurrentis
- Trench fever - Rickettsia quintana
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
Trypanasomatids gambiense
- West Africa
- human reservoir
– Glossina palpalis group, lives by rivers
– chronic - years to develop
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)
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
Siphonaptera
- 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
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
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)
Malaria
Diagnosis
- Giemsa - stained blood smears thick smear thin smear Rapid tests
- Travel history
- “autochthonous” malaria
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
flea vectors
- 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)
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
Onchocerca volvulus
Infection
- Micro migrating in skin ->
intense itching -> 2o inf
- months to years, then skin degeneration (pachydermia)
- may get eye -> blindness
Plasmodium vivax
- 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
Trypanosoma cruzi
basic info
- Chagas’ Disease
- Amastigote in human, Epimastigote in vector
- in america, spread by tratomes (bugs), tranfusions or rodents
Chelicerata
mites and ticks
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
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
Plasmodium ovale
- 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
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
Argasids
- soft ticks, can't see head
– nocturnal feeders, only stay on host for a few minutes
– bird ticks
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
Taenia saginata
- 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
Plasmodium malariae
- no hypnozoites but may persist in bloodstream (low levels)
- 72 hour periodicity
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)
Ixodidae
- 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
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
Taenia solium
- 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
Plasmodium falciparum
- invade red cells of all ages
- the sickle-shaped gametocyte
- 48 hour periodicity
Leishmaniasis
Basic info
- Amastigote (in phagolysosome until ruptire) in human, promastigote in vector
- can cause visceral or Cutaneous / Mucocutaneous leishmaniasis
- mainly epizootic
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
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
Tapeworms
- 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
Falciparum malaria
- 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
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
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
Necator americanus
Diagnosisa and treatment
- diagnose via eggs in stool
- prevent w/ sanitary sewage disposal, shoes, and treating infected
Ancylostoma duodenale
Diagnosis and Treatment
- diagnose via eggs in stool
- prevent w/ sanitary sewage disposal, shoes, and treating infected
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
Cysticercosis
- 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
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
Mites
basic info
- Lifecycle is Egg, larva, 2-3 nymph stages, adult
- Breate via trachea branching
– cutaneous in small "Astigmata”
Strongyloides stercoralis
Basic info
- Intestinal nematodes transmitted via skin penetration
- like hookworm, but eggs hatch in intestine and motile larvae passed in feces
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)
trematodes
- flukes - flatworms
- live in GI, bile ducts, lungs, BVs
- complicated life cycles -
asexual in snail and sexual in humans
Malaria
genetic resistant
- Sickle cell trait
- Thalassemia
- Glucose-6-phosphate dehydrogenase deficiency
- Ovalocytosis
- Duffy blood group negative
Sarcoptes scabei
- adult is 250 µM long
- causes scabies in humans and "mange" in animals
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
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
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
Babesiosis
- mild illness
- Endemic in parts of US
- May be mistaken for malaria
- intra-erythrocytic
- Tick-borne - Ixodesscapularis
- Reservoir – white-footed mouse
Dust mites
- D. pteronyssinus
- D. farinae
- Euroglyphus maynei
- in every household, prefer humid air
Cutaneous larva migrans
- when hookworm larvae of dog enter's human skin
- produce migrating inflam rxn w/ creeping eruption - Similar symptoms w/ bird schistosomes
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
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
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
Mite vectors
- Scrub typhus - (Rickettsia tsutsugamushi)
- Rickettsial pox (Rickettsia akari)
Visceral larva migrans
- 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
Trichomonas vaginalis
Clinical Presentation
- Women have yellow discharge, itching and burning
- Men no symptoms, maybe urethritis
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.
Toxoplasma gondii
Epidemiology
- big in developing countries and france
- infection via Oocyst from cat feces or Cyst (bradyzoites) from undercooked meat
DDT/Pyrethrins
- D used to delouse soldiers in WWII
- P from flowers, later on synthetic (permethrin and deltamethrin)
- Target Na+ channel to slow
down nerve conduction
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
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
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
Organophosporous and Carbamates
- nerve poisons
- Target ACh esterase - bind to serine, prevent recycling
of Ach in synapse
Bacillus thuringensis
- 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
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
Toxoplasma gondii
Diagnosis and Treatment
- Serology
- Culture/inoculation of mice

- Antifolates (Pyrimethamine/sulfadiazine)
- Atovaquone
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)
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
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
Cryptosporidium
Transmission
- Cysts are chlorine-resistant!!!!
- Transmitted via water and food
- Outbreaks (>100 in US) - from Day-care, water supplies - big on in Milwaukee
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
Cryptosporidium hominis
- Humans only, main cause of outbreaks
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
Cryptosporidium parvum
- humans in cattle, main cuase of sporatic cases
- the main one in developing countries
Cyclospora
Basic Info
- like Cryptosporidium but bigger
- No animal reservoir
- Outbreaks from Guatemalan raspberries
- Treatment - Bactrim