Parasitology

Question 1

treatment for amebic (amebiasis) and flagellated (giardiasis, trichomoniasis) diseases

Answer 1

PO nitroimidazoles: metronidazole, tinidazole

Question 2

nitroimidazoles MOA

Answer 2

nitroaryl compounds – reduce to nitro radical anions– react with O2–superoxide radical anions– reduced to H2O2– OH radical. considered reactive oxygen species and are implicated in damage to the parasite

Question 3

treatment for intestinal nematodes (roundworm)

Answer 3

PO benzimidazoles: mebendazole, albendazole

Question 4

benzimidazole MOA

Answer 4

bind to tubulin protein, preventing its polymerization to form the cytoskeleton of eukaryotes

Question 5

treatment for blood nematodes (roundworm)

Answer 5

PO semisynthetic macrolide: ivermectin

Question 6

ivermectin MOA

Answer 6

selectively/strongly binds to glutamate-gated chloride ion channels in invertebrate nerve/muscle cells– increase permeability of cell membrane to chloride– hyperpolarization– paralysis/death

Question 7

treatment for cestodes (tapeworm)

Answer 7

PO isoquinolone derivative: praziquantal

Question 8

praziquantal MOA

Answer 8

in human intestinal lumen: Ca redistribution in worm, leading to muscle contraction and paralysis. in blood: damages worm tegument, resulting in attack by human antibodies

Question 9

what are the 4 protozoa

Answer 9

amoebae, flagellates, ciliates, sporozoa

Question 10

defining characteristic of amoebae

Answer 10

“ameboid” appearance meaning it changes shape

Question 11

defining characteristic of flagellates

Answer 11

have one or more whiplike flagella (flagellatus=whip)

Question 12

defining characteristic of sporozoa

Answer 12

complex life cycle with alternating sexual and asexual reproductive phases

Question 13

what are the 3 helminths

Answer 13

nematodes, cestodes, trematodes

Question 14

nematodes are

Answer 14

roundworms

Question 15

cestodes are

Answer 15

tapeworms

Question 16

trematodes are

Answer 16

flatworms/flukes

Question 17

defining characteristic of nematodes

Answer 17

large size, cylindrical form, unsegmented bodies

Question 18

defining characteristics of cestodes

Answer 18

25-50 ft length, flat, ribbonlike. head is 4 muscular, cup-shaped sucking disks, crown of hooklets

Question 19

what is an individual segment of a cestode called

Answer 19

proglottid

Question 20

what is a chain of proglottids called

Answer 20

strobila

Question 21

defining characteristics of trematodes

Answer 21

flat, fleshy, leaf-shaped/football-shaped worms with 2 muscular suckers

Question 22

important note for life cycle of trematodes?

Answer 22

require intermediate hosts to complete their life cycle which are most commonly mollusks (snails, clams)

Question 23

important note for life cycle of cestodes?

Answer 23

definitive hosts are humans. intermediate hosts harbor larval forms. if humans become intermediate hosts then death is possible and great damage.

Question 24

where are parasites more likely to be, geographically

Answer 24

tropics and subtropics

Question 25

what info can you find about parasites at cdc.gov

Answer 25

life cycles, epidemiology, pathogenesis, prophylaxis, therapy

Question 26

what are some nomenclature clues

Answer 26

location (geographic), individual, source or vector, sign or symptom

Question 27

parasite modes of transmission

Answer 27

most commonly ingestion of contaminated food or water, insect bite, direct contact thru skin. respiratory droplet transmission is very uncommon

Question 28

why do you think we named protozoa meaning "first animal"

Answer 28

they are unicellular eukaryotes, display characteristics associated with animals: motility, heterotrophy

Question 29

what does heterotrophy mean

Answer 29

organisms incapable of food production, are food producers

Question 30

describe very generally the protozoan life cycle

Answer 30

cyst and trophozoite cycle.

Question 31

what type of personality is a cyst

Answer 31

SURVIVOR: vegetative, nonmotile, quiescent, resistant, infective

Question 32

what type of personality is a trophozoite

Answer 32

DESTROYER: active, motile, feeding

Question 33

how do amoebae replicate

Answer 33

binary fission (splitting the trophozoite), development of numerous trophozoites within the mature multinucleated cyst

Question 34

how do amoebae move

Answer 34

pseudopodia (false foot): protoplasmic flow, via extension of the pseudopod, extrusion of ectoplasm, and snail like movement

Question 35

when does the cyst form develop

Answer 35

drop of temperature or humidity

Question 36

respiration of amoebae?

Answer 36

facultative anaerobe

Question 37

how do amoebae get their nutrition

Answer 37

pinocytosis, phagocytosis

Question 38

what kind of relationship do amoebae have with their host

Answer 38

commensal/symbiotic relationship: one species benefits, other is neither harmed nor helped

Question 39

describe the general life cycle of helminths?

Answer 39

egg--> larvae--> adult male and adult female (cycle)

Question 40

how are nematode infections of the intestinal tract confirmed

Answer 40

identification of characteristic eggs in the feces

Question 41

how are blood roundworms characterized

Answer 41

they are infections transmitted by biting insects such as mosquitoes or flies. they produce filariae

Question 42

what are the larval forms of blood roundwarms called

Answer 42

microfilariae

Question 43

reproductive organs of cestodes?

Answer 43

hermaphroditic: male and female organs are present in each mature proglottid

Question 44

defining characteristics of cestode eggs

Answer 44

nonoperculated, contain hexacanth (6 hooked) embryo

Question 45

how do cestodes get nutrition?

Answer 45

lack a digestive system so absorb food from host intestine through the soft body wall of the worm

Question 46

the naming of a disease follows this: _____ "iasis"

Answer 46

genus-iasis

Question 47

cysts are associated with __

Answer 47

protozoa

Question 48

eggs are associated with ___

Answer 48

helminths

Question 49

proglottid and strobila are associated with ____

Answer 49

cestodes

Question 50

malaria is associated with ____

Answer 50

sporozoa

Question 51

filariae are associated with ____

Answer 51

nematodes

Question 52

the larval form of blood roundworms are called ____

Answer 52

microfilariae

Question 53

trichomoniasis is associated with _____

Answer 53

flagellates