Worms and Flukes

Question 1

which are the most successful human parasites

Answer 1

nematodes

Question 2

what are the 7 types of worm parasites

Answer 2

pinworms
common/giant roundworm
hookworm
whipworm
threadworm
tapeworm
blood flukes

Question 3

distinctive features of pinworms?

Answer 3

-small, visible white roundworm
-humans are only host for entire life cycle
-in order to lay eggs, which require more O2 to develop, females emerge from anus and lay them on skin

Question 4

how are pinworms transmitted

Answer 4

eggs ingested by the fecal oral route, from surfaces including clothes, or by swallowing dust containing eggs

Question 5

who is infected by pinworms

Answer 5

almost all children, adults are asymptomatic

Question 6

symptoms of pinworms

Answer 6

intense itching of perianal area - resolves w/in 6 weeks

Question 7

pinworm treatment

Answer 7

Pyrantel
hand washing and normal hygiene reduces transmission and vaseline to perianal area prevents eggs from getting O2

Question 8

common/giant roundworm distinctive features

Answer 8

-large
-humans are again the only host
- lung migration

Question 9

what are giant roundworm eggs resistant to and susceptible to

Answer 9

resistant to chemical inactivation, susceptible to sunlight
- need to incubate several weeks to become infectious, but can remain viable for years

Question 10

describe common roundworm lung migration

Answer 10

• larva inside eggs are ingested from contaminated soil
• hatch in small intest. and larvae burrow thru wall and carried to lungs in blood
• size of adult can result in blocking the intestine or bile or other ducts or perforations

Question 11

symptoms of common roundworm

Answer 11

few eggs and worms can remain asymptomatic
-insomnia, malnutrition

Question 12

how long will common roundworm infection last

Answer 12

1-2 years if left untreated and not reinfected (the lifespan of the adult)

Question 13

common roundworm diagnosis

Answer 13

-eggs seen in stool specimens, which may also contain clearly visible adult
- high levels of eosinophils

Question 14

common roundworm treatment

Answer 14

mebendazole

Question 15

common roundworm prevention

Answer 15

improved sanitation, particularly human waste disposal

Question 16

hookworm features

Answer 16

-eggs and early stage larvae mature in soil and give rise to motile larva that is able to penetrate the skin
- smaller, more often asymptomatic
- no physical damage but injure by attachment and sucking blood

Question 17

hookworm transmission

Answer 17

• eggs resistant in the soil, eggs are larvae susceptible to sunlight
• eggs hatch in the soil and the developing larvae can live for several weeks in the absence of a host

Question 18

hookworm symptoms

Answer 18

• larvae enters thru skin, usually the foot causing intense itching (ground itch)
• migrates thru the blood system to the lungs
• coughed upwards, swallowed and reside in small intestine
• anemia, fatigue, weight loss, pneumonia, eosinophilia

Question 19

hookworm diagnosis

Answer 19

appearance of eggs in stool specimens on “O and P” (stool test)

Question 20

hookworm treatment

Answer 20

mebendazole

Question 21

hookworm prevention

Answer 21

improved sanitation, shoes

Question 22

whipworm features

Answer 22

• big
• thin coiled majority of the body is the esophagus that the worm threads into the mucosa of the colon
• no lung migration

Question 23

whipworm clinical manifestations/pathogenisis

Answer 23

• mature or ineffective eggs are ingested directly or in food & hatch inside small intestine
• adults migrate into colon and reside for 4+ years ( no lung migration)
• light infections are asymptomatic
• severe infections = GI issues, rectal prolapse, weight loss, nutritional deficiencies, anemia (especially in children)

Question 24

whipworm diagnosis

Answer 24

stool O and P exam shows whipworm eggs

Question 25

whipworm treatment

Answer 25

bendazole with ivermectin

Question 26

threadworm features

Answer 26

-like hookworm, larvae actively seek hosts and penetrate skin (foot)
- unique among helminths can replicate in the host
- also can replicate without a host in the soil (free-living cycle)

Question 27

tapeworm features

Answer 27

• adult flatworm is a family of individuals
• segmented large worms that reproduce by fragmentation
  -require human definitive host and a 2nd vertebrate host
• adults are long lived
• eggs eaten by intermediate hosts

Question 28

tapeworm hosts

Answer 28

• all except pork tapeworm requires 2 hosts, with humans as a necessary definitive host
• pork tapeworm humans can also be intermediate and only host

Question 29

tapeworm diagnosis

Answer 29

bendazoles

Question 30

tapeworm prevention

Answer 30

thorough cooking, adequate sanitation

Question 31

blood flukes features

Answer 31

• reside in host organs other than intestine
• ## large visible animals

Question 32

blood flukes aka

Answer 32

schistosoma

Question 33

blood flukes transmission

Answer 33

• swimming larvae penetrate skin, travel in blood and inhabit veins draining intestine and bladder
  -immune responses cause significant tissue damage

Question 34

blood flukes prevention

Answer 34

avoid swimming in fresh water in high incidence areas
- 2nd most fatal parasite after malaria