32 - Overview and Helminths (Wilson)

Question 1

risk factors for parasitic infection

Answer 1

climate
contamination of food/water
access to medical care
sanitation
insect vectors
immunity
age
nutrition

Question 2

protozoa definition

Answer 2

unicellular

multiply in human host

Question 3

helminths definition

Answer 3

mulicellular worms

life cycle cannot be completed in single host

Question 4

what helminths have autoinfection

Answer 4

strongyloides stercoralis

hymenolepis nana

Question 5

definitive host

Answer 5

harbors adult (sexual) stage

Question 6

intermediate host

Answer 6

harbors larval (asexual) stage

Question 7

reservoir

Answer 7

animal (definitive) host or location that maintians parasite life cycle

Question 8

vector

Answer 8

insect that allows parasite to develop into infectious form and transmit parasite

Question 9

types of helminths

Answer 9

nematode (roundworm)

platyhelminths (flatworms)

Question 10

types of nematodes

Answer 10

intestinal (fecal oral)
filariae (vector borne)
pathologic larval stages

Question 11

intestinal nematodes

Answer 11

adult worms reside in gut

spread through fecal oral route

Question 12

geohelminth

Answer 12

essential part of life cycle occurs in soil

all nematodes except enterobius vermicularis

Question 13

treatment of invasive parasitic disease

Answer 13

use drugs that are absorbed with good systemic levels

Question 14

treatment of non infasive parasitic disease

Answer 14

use drugs that are poorly absorbed

Question 15

enterobius vermicularis life cycle

Answer 15

fecal oral contamination-ingest eggs
adults develop in intestines
migrate to perianal skin
lay eggs on skin
eggs embryonate and become infectious
infectious eggs ingested by next host

Question 16

test for e. vermicularis

Answer 16

scotch tape test

stool ova and parasite

Question 17

symptoms of e. vermicularis

Answer 17

pruritus ani

Question 18

e. vermicularis characteristics

Answer 18

not a geohelminth
fecal oral transmission
common in young children
person to person spread

Question 19

ascaris lumbricoides life cycle

Answer 19

ingest egg
larvae excyst in intestine
migrate through venous system to lungs
migrate up lungs and are swallowed
become adults in intestines
adults release eggs into stool

Question 20

ascaris lumbricoides symptoms

Answer 20

pulmonary phase: Loeffler's syndrome( eosinophilia, pulmonary infiltrates), wheezing
intestinal phase: dyspepsia
wandering ascarids (bile duct, pancreatic duct, intestinal obstruction)

Question 21

ascaris lumbricoides characteristics

Answer 21

fecal oral spread
geohelminth
reservoir in soil
largest intestinal nematode

Question 22

hook worm life cycle

Answer 22

contact filariform larvae in soil
larvae penetrate skin
enter lymphatics and travel to lungs
travel through lungs and swallowed
adults attach to intestinal mucosa, cause blood loss and anemia
excrete egg in stool

Question 23

hook worm symptoms

Answer 23

skin-ground itch (dermatitis)
pneumonitis with eosinophilia
iron deficient anemia

Question 24

hook worm characterisitcs

Answer 24

geohelminth-2 week development in soil

Question 25

example of treatment of parasites residing in lumen

Answer 25

enterobius vermicularis, ascaris lumricoides, hookworms use benzimidazoles (mebendazole, albendazole)

Question 26

strongyloides stercoralis life cycle

Answer 26

filariform larvae penetrate skin migrate to lungs swallowed and become adult worms adults release eggs that turn into rhabditiform larvae and released in feces rhabditiform develop into filariform larvae

Question 27

rhabditiform develop into filariform larvae where

Answer 27

externally in soil AUTOINFECTION: on perianal skin internally during immunocompromise

Question 28

stronglyoides acute infection

Answer 28

``` skin rash (rash and eosinophilia) pulmonary phase (migratory pneumonitis) intestinal phase ```

Question 29

stronglyoides chronic persistent infection

Answer 29

due to auto infection

Question 30

stronglyoides hyperinfection syndrome

Answer 30

``` immunocompromised states gram negative infection meningitis pneumonia eosinophilia ```

Question 31

treatment of stronglyoides

Answer 31

absorbing medicine | ivermectin

Question 32

what are filariae

Answer 32

adult worms in blood or lymph vessels | transmitted by insect bite

Question 33

what are microfilariae

Answer 33

immature larvae in blood, skin, or eye

Question 34

examples of lymphatic dwelling filariae

Answer 34

wuchereria bancrofti | brugia malayi

Question 35

life cycle of lymphatic dwelling filariae

Answer 35

mosquito vector introduces larvae into blood adults in lymph vessels and lymph nodes microfilariae in blood

Question 36

acute lymphatic filariae syndromes

Answer 36

acute adenolymphangitis | filarial fever

Question 37

chronic obstructive filariae symptoms

Answer 37

elephantiasis (poor lymph drainage) | lymph vessels rupture (ascities, effusion, chyluria)

Question 38

onchocerca volvulus causes

Answer 38

river blindness | 2nd most common cause of infectious blindness worldwide

Question 39

onchocerca volvulus life cycle

Answer 39

transmitted by black fly | microfilaria in skin

Question 40

onchocerca volvulus symptoms

Answer 40

dermatitis subcutaneous nodules sclerosing keratitis optic atrophy

Question 41

treatment of lymphatic filariae (wuchereria bancrofti, brugia malayi)

Answer 41

absorbing meds | diethylcarbamazine (microfilaria only)

Question 42

treatment of onchocerca volvulus

Answer 42

absorbing meds | ivermectin