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34 Cards in this Set
- Front
- Back
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Ecto vs Enco parasites?
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Ecto = insects, arachnida
Endo = Helminths, protozoa |
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Characteristics of parasites. (5)
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1. free living
2. single celled 3. eucaryotic cells w cytoplasmic membrane and 4. cellular organelles (including 1 or 2 nuclei, mitochondria, food vacuoles and ER) 5. Variable size (5um-2mm) |
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What is the cytoplasmic layers of protozoa? (2)
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Outer layer of cytoplasm (ectoplasm) and an innter layer (endoplasm)
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Survival mechanism of protozoa?
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- when expomsed to new envt (temp change, GI tract or chamical agents) they can secrete a protective coat and shrink into a round armoured form (cyst). Cyst is infective when injected by humans and following injestion can converts back to motie form (trophozoite)
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Motile and infective form of protozoa
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Infective = cyst
Motile = trophozoite |
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Protozoa that cause diarrhea (3) and type of diarrhea (bloody, sever,, non bloody)
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- all cause diarrhea
- E. histolytica (blood diarrhea) - Giardia (non bloody) - Cryptosporisium (severe diarrhea in patients with defective immune systems ex aids |
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Characteristics of heminths
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1. multicellular
2. organized internal structures 3. LIVING worms dont cause an immune rxn within a normal host, DEAD worms or EGGS cause a marked response --> increase Eosinophils 4. Complex life cycles (egg, embryo, larva, adult) |
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2 main catagories of helminths?
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1. Nematodes (roundworms)
2. Platyhelminthes (flatworms) |
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Structure of nematodes
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- adult form = nonsegmented w complete digestive tube (mouth to anus)
ex Ascarasis |
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Structure of Platyhelminthes (2 types)
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1. Cestodes (tapeworms)
- adult form = segmented w scolex and proglottids 2. Trematodes (flukes) - adult form = nonsegmetned, incomplete digestive tract - in some species, females reside within groove (schists) of males Ex schistosoma species |
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Which intestinal protozoa is transmitted fecal orally ( in contaminated food or H20) and is injected as a cyst which differentiates in ileum to become a motile trophozoite and causing bloody loose diarrhea?
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Entamoeba histolytica
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Which protozoa can invade portal circulation creating an absess that causes RUQ pain, weight loss, and liver/pulmonary absess?
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Entamoeba histolytica
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Dx and Tx for Entamoeba histolytica?
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Dx: diarrhea specimen (active state) - trophozoite w injected RBCs
Hard stool specimen (carrier state): 4 nuclei syst Serology Tx: active state (Metronidazole) - drain absess (if severe) - carrier: Indoquinol, Diloxamide |
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Which protozao transmitted fecalorally from contaminated food/water as a cyst --> duodenum ---> differentiation into trophozoite --> attached to duodenal wall via suction dist (no invasion) --> damage to microvilli --> inflammation --> diarrhea (foul smelling, fatty, non bloody) + malabsortion and weight loss?
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Giardia
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Dx and Tx of Giardia?
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Dx: Stool ova and parasite exam
- diarrheal specimen (active state = 2 nuclei, 4 flagella) - hard stool specimen (carrier state) - 4 nuclei cyst Tx: Metronidazole |
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Which protozoa is transmitted fecalorally from animals to humans ( or contaminated city water reservoirs) --> oocyst injested --> oocyst release sporozoite in small intestine --> sporozoites differentiate into trophozoites --> attach to intestinal wall --> diarrhea (watery, nonbloody) + ab pain?
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Cryptosporidiosis
NB: In immunocompromised host can cause prolonged, severe diarrhea and malnutrition |
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Dx and Tx of Cryptosporidiosis?
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Dx: stool sample (oocyst seen using acid fast stain)
serology Tx: self-limiting |
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Which are the tissue protozoa (2)
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1. Toxoplasma gondii
2. Plasmodium malariae |
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Which protozoa is injected as a cyst ( in undercooked meat, cat feces) --> in small intestine cyst release invasive form --> penetrate intestinal wall --> phagocytosed and disseminated by M0 --> infect and damage distant sites --> mono-like symptoms + encephalitis, fever, lymphnode, liver and spleen enlargement (immunocompromized)?
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Toxoplasma gondii
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Dx and Tx of Toxoplasma gondii?
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Dx: serology (IgM in infants), tissue biopsy, trophozoites (active) cysts (dormant), CT, MRI or head
Tx: Sulfonamide and Pyrimethamine |
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Which protozoa can cross the placenta from mother with active primary infection to fetus?
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Toxoplasma gondii
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What form of the malaria lifecyle mosquitos actually transmitting to bitten host?
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sporozoite
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What happens to sporozoite in liver?
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infected hepatocytes --> sporozoite divides into merzoites --> liver cells burst --> release merzoites into blood
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What happens to merzoites once in blood?
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They invade RBCs and develop into trophodoites --> trophozoites divides into many merozoites --> merozoites burst infected RBC --> spread to other RBCs
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Symptoms of malaria?
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- Fever, chills and anemia (with each burst of merzoites)
- knobs form in infected RBCs and cause RBCs to stick to capillary walls/venules --> vessel occlusion and hemmorage --> damage to brain (cerebral malaria) + kidneys + lungs - RBCs become less flexible --> accumulate and destoryed in spleen --> speenomegaly |
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What types of RBCs do vivax/ovale, falciparum and malaria infect?
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P. vivax/ovale - young RBCs only
P. malariae - old RBCs only P. falciporum - ALL RBCS! (MOST SEVERE) |
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Life cycles of vivax/ovale, falciparum and malaria and significance?
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vivax/ovale - 48hrs
falciparum - 36-48 malaria - 72hrs * falciparum causes most frequent and irregular fevers |
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Dx and Tx of Malaria?
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Dx:
- blood smear: tropozoite shape: small rings (F), large irregular rings (V/O), band or rectangular (M) gametocyte shapes: bananalike (F), round (V/O/M) Tx: Chloroquine, mefloquine, primaquine |
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Which helminths is transmitted recalorally (eggs injested in contaminated soil) --> hatch in small intestine --> larva invade intestinal wall --> enter circulation --> lungs --> alveoli --> tracha --> cause local inflammation (pnemonia) OR go to pharynx --> swallowed --> larva matura in small intestine --> adults lie in lumen and consume host nutrients --> malnutrition + ab cramping?
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Ascarisis (round worm)
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Dx and Tx of Ascarisis?
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Dx: Stool (detect eggs with rough surface); eosinophilia
Tx: pyrantel pamoate, mebendazole, albendazole |
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Which helminths is tranmitted fecal-cutaneously (penetrate skin of feet) --> cause local itch +/OR enter blood stream --> lungs --> alveoli --> trachea --> resp tract inflammation (pneumonia) +/OR enter pharynx --> swallowed --mature in SI --> attach to mucosaliva cutting plates of teeth --> gastroenteritis (diarhea, wt loss, ab pain) + anemia (suck blood from host)?
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Hookwork
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Dx and Tx of hookworm?
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Dx: stool cample (detect eggs not larva) eosinophilia
Tx: Mebendazole, pyrantel pamate, iron and folate acid for anemia |
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Which helminths infects fecalcutaneouly as infectious filariform --> local itching +/OR --> lungs --> alveoli --> trachea --> resp tract inflammation (pnemonia) +/OR enter pharynx --> swalled --> larva mature in SI --> mate --> females invade mucose and lay eggs --> eggs hatch into larva in intestinal wall --> ab pain + diarrhea
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Strongyloidiaes
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Dx and tx of Strongyloidiaes?
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Dx: stool (detect larva, not eggs), eosinophilia, string test (swalow long string to pull out larvae)
Tx: thiabendazole, ivermectin |
