Parasitic Disease Flashcards
Parasites are
eukaryotic
multicellular and single cellular
helminths
multicellular worms
macroscopic
differentiated and complex organs
Protozoa
microscopic
single cell amaeba
replicate intra or extracellularly
describe life cycle of Ascaris Lumbricoides (round worms/nematodes)
Life cycle:
highly resistant to environment egg
larvae develops in egg and viable for years
eggs are ingested and hatch in small intestine
larvae penetrate intestinal wall to blood stream, then lungs (bronchioles) where they move up trachea and are swallowed to return to small intestine to feed.
adult nematode lives and feeds in small intestine
lays 2X10^6 eggs/day
eggs develop outside body where not too cold <30 C 86 F
parthenogenesis of ascaris lumbricoides (round worms/nematodes)
85% asymptomatic abdominal pain/nausea malnutrition fever & pneumonia (hemorrhagic pneumonia) peritonitis
treatment of ascaris lumbricoides (round worms/nematodes)
albendazole - blocks tubulin polymerization and prevents glucose uptake
Describe the geographical restriction of flukes (trematodes)
a Helminth
requires specific snail host which restricts distribution
Compare the properties of intracellular parasites and describe how those properties relate to the diseases they cause
intracellular parasite is transmitted through vectors and are sensitive to dryness.
causes blood and tissue diseases
Cryptosporidiosis intracellular parasite
can be protozoa
Compare the properties of extracellular parasites and describe how those properties relate to the diseases they cause
extracellular parasite includes
protozoa
transmitted by fecal-oral route
switches between active trophozite and dormant cyst
what is protozoa?
microscopic (2-100mm), single cell amaeba, replicate intra or extracellularly
classified by locomotion
trophozite
actively growing larger multiply in diarrhea motile non-infectious
cyst
smaller dormant resistant to heat and dryness infectious in solid feces
Describe the life cycle of Entamoebaehistolytica
Life cycle of Entamoebaehistolytica:
cysts is ingested through contaminated food/water
Excystation in small intestine and infects large intestine
becomes trophyzoite (causes colitis & liver abscess)
encystation in colon
excreted in feces
repeats
how are protozoa classified?
by locomotion
- Ameoebas - cytoplasmic projections
- flagellates - rotate flagella
- ciliates - beat hair like cilia
- Sporozoa - non motile adult forms
pathology, diagnosis and treatment of Entamoebae histolytica
pathology - asymptomatic infection leads to excretion
invasive infection leads to desimination
diagnosis - cysts in solid feces. trophozoite in diarrhea or aspiration of liver abscess. Antibody test for invasive amebiasis
treatment -antibiotic called metronidazole
Describe the pathology and treatment of Plasmodium
Treatment:
ACT
injectible artesunate followed by ACT
chloroquine if other than P. falciparum
pathology: enlarged liver from sporozoites entering it enlarged spleen jaundice anemia from lysed RBC fever
Describe the pathology and treatment of Plasmodium
pathology: fever indicates time it takes for merozoites to divide and lyse red blood cells before another cycle of reinfection and division
causes malaria (blood infection)
Treatment:
(uncomplicated) Artemisinin-based combination therapies (ACT)
(severe) Injectable artesunate, then ACT
different than falciparum - chloroquine
Merozoites from plasmodium
inavde RBC
divide asexually
mature
in 2-3 days merozoites lyse RBC and infect new RBCs
Malaria
humans are only reservoir (asexual phase)
transmission by mosquito vector (sexual phase)
Plasmodia has?
antigenic variation of pFEMP-1 (protein for RBC adhesion)
and not directed by DNA rearrangement
Giardia lamblia
“Monkey face”
2 nuclei
