Test 3: Worms and Flukes

Question 1

Which of these are considered parasites in the field of infectious diseases?
a. protozoans
b. bacteria
c. some insects
d. a & c
e. all of these

Answer 1

D. protozoans and some insects

Question 2

What is the biggest group of worms?

Answer 2

• nematodes (giant roundworm)
  ascaris lumbicodes

Question 3

What are the big 3 soil transmitted diseases?

Answer 3

• giant roundworm
• hookworm
• whipworm
• 4th: threadworm with endogenous/atuo-reinfection ability meaning it can multiply without going outside the body and multiply in the soil

Question 4

What are the other 2 types of worms?

Answer 4

• tapeworms
• flukes

Question 5

What can cause more human disease than any other infection?

Answer 5

• worms and flukes to low CDC reportability

Question 6

What is the main distinction of hookworm?

Answer 6

• actively seeks human host by living on plant and going through human foot

Question 7

What is the most important nematode worms?

Answer 7

• common roundworm: ascaris lumbridcoides (most common in tropics)
• whipworm: trichuris trichiura
• hookworm: necator Americanus and ancylostoma duodenale
• threadworm: strongyloides stercoralis
• pinworm: enterobius vermicularis (most common in US)

Question 8

What is the most successful human parasite?

Answer 8

nematodes

Question 9

How common are soil transmitted helminths in US?

Answer 9

no one knows

Question 10

What is the #1 US prevalence worm?

Answer 10

• pinworms: enterobius vermicularis
• small, white
• humans are only host for the entire life cycle
• to lay eggs: requires more oxygen iso female will emerge from any and lay them on skin at night and dies

Question 11

What is the habitat and transmission of pinworms: enterobius vermicularis?

Answer 11

• more often in urban areas (highest in US)
• fecal-oral route from surfaces or by swallowing dust

Question 12

What is the epidemiology of pinworms: enterobius vermicularis?

Answer 12

• most common parasite in US
• almost all children infected with siblings in same household infected

Question 13

What is the pathogenesis of pinworms: enterobius vermicularis?

Answer 13

• intense itching of perineal area
• resolves about 6 weeks

Question 14

What is the dx, tx, and prevention of pinworms: enterobius vermicularis?

Answer 14

• dx: scotch tape
• tx: pinworm medicine: pyrantel, petroleum jelly can prevent eggs from getting oxygen
• prevention: hand washing and normal hygiene

Question 15

What is the #2 US associated but #1 medically important helminth in the US and world?

Answer 15

• nematode common roundworm: ascaris lumbricodes

Question 16

What is the distinctive features of nematode roundworm: ascaris lumbricodes?

Answer 16

• large roundworm
• most abundant in tropics
• unusual and lung migration

Question 17

What is the habitat and transmission of nematode roundworm: ascaris lumbricodes?

Answer 17

• Southeast Asia
• eggs are resistant to chemical inactivation but susceptible to sunlight so must incubate several weeks in warm soil to become infectious
• can remain viable for years

Question 18

What is the epidemiology nematode roundworm: ascaris lumbricodes?

Answer 18

• human waste as fertilizer and consuming veggies

Question 19

What are the clinical manifestations of nematode roundworm: ascaris lumbricodes?

Answer 19

• larva inside eggs are ingested from contaminated soil
• hatch in small intestine and larva burrow through wall and carries to lungs in blood
• size of the adult can block intestine or ducts/perforations but with many worms
• if few= asymptomatic
• symptoms: insomnia, GI problems, malnutrition
• infection untreated: 1-2 years which is the life span of the adult

Question 20

What is the dx, tx, and prevention of nematode roundworm: ascaris lumbricodes?

Answer 20

• dx: eggs seen in stool specimens with clearly visible adult
• tx: mebendazole
• prevention: improved sanitation of human waste disposal

Question 21

What is #3 US associated helminth?

Answer 21

• hookworm: necator americanus

Question 22

What are the distinctive features of hookworm: necator americanus?

Answer 22

• motile larva that penetrates skin (typically foot)
• much smaller, usually asymptomatic
• no damage but attachment and such blood could cause anemia

Question 23

What is the habitat and transmission of hookworm: necator americanus?

Answer 23

• widespread mostly tropics
• eggs are restraint in soil and must be warm. susceptible to sunlight
• eggs hatch in soil

Question 24

What is the epidemiology of hookworm: necator americanus?

Answer 24

• walking in latrine areas

Question 25

What are the clinical manifetions, pathogenesis of hookworm: *necator americanus*?

Answer 25

- ground itch - migrates though blood to lungs - coughing upwards, swallow, and then revised in small intestine - heavy burdens can cause anemia, fatigue, wt loss, pneumonia like sx, eosinophilia

Question 26

What is the dx, tx, prevention of hookworm: *necator americanus*?

Answer 26

- dx: omars thing - tx: **mebendazole** - prevention: improved sanitation, shoes to block infection

Question 27

What is the #4 US associated helminth?

Answer 27

- whipworm: *trichurus trichuria*

Question 28

What are the distinctive features of whipworm: *trichurus trichuria*?

Answer 28

- big, whip like - thread into mucosa of large intestine - **no lung migration**

Question 29

What is the habitat and transmission of whipworm: *trichurus trichuria*?

Answer 29

- outdoor latrines - nightsoil - most prevalent in children

Question 30

What are the clinical manifestations and pathogenesis of whipworm: *trichurus trichuria*?

Answer 30

- hatch inside small intestine - migrate into colon and rside for 4+ year - **no lung migration** - often asymptomatic - severe infection: rectal prolapse - in children sometimes: weight loss, nutritional deficiencies, anemia

Question 31

What is the dx, tx, and prevention of whipworm: *trichurus trichuria*?

Answer 31

- dx: Omar thing - tx: combing **bendazole** with ivermectin

Question 32

What do we need to know about 4th threadworm?

Answer 32

- in kentucky, Tennessee (appalachians) - similar to hookworm in that is actively seeks host and penetrates skin of foot - **uniquely, can replicate in the host and replicate without a host in the soil**

Question 33

What is another name for cestode?

Answer 33

tapeworm

Question 34

What is another name for trematodes?

Answer 34

fluke

Question 35

What is the distinctive feature of tapeworm/cestode?

Answer 35

- each body segmentation that fragments off is a full organism

Question 36

How do tapeworm/cestodes reproduce?

Answer 36

- fragmentation

Question 37

What do tapeworm/cestodes require?

Answer 37

- human definitive host - animals typically as intermediate host

Question 38

How are tapeworms transmitted?

Answer 38

- not an issue for vegetarians - the 2nd host is in cows or eggs where the eggs mature - consumed in meets in muscle cysts and reside in definitive host of a human

Question 39

How long do tapeworms lived?

Answer 39

- long lived (years or decades), shed eggs or segments with eggs - eggs eaten by intermediates hosts like cow and mature to juveniles that migrate into muscle and form cysts - cestodes are acquired when a human (definitive host) consumes a second intermediate hosts with tissue cysts

Question 40

What is it called when you have an adult worm that resides in the gut?

Answer 40

- taenasis

Question 41

Why is the pork tapeworm/ Tania sodium more dangerous?

Answer 41

- only require 1 host. humans can be the intermediate host and definitive host - this allow for muscle cysts or brain cysts in humans= cysticercosis

Question 42

What is the fish tapeworm called?

Answer 42

- d. latum *in salmon* (different genus)

Question 43

What is the dx for cestode?

Answer 43

- stool with worm segments

Question 44

What is the tx for cestode/tapeworms?

Answer 44

- bendazoles

Question 45

What is the prevention for cestode/tapeworm?

Answer 45

- thorough cooking and adequate sanitation (pork requires adequate cooking and sanitation)

Question 46

T/F: Blood flukes/schistosoma can reside outside of intestines

Answer 46

True!

Question 47

How are blood flukes/schistosoma transmitted?

Answer 47

- swimming larva penetrate skin, travel in blood, inhabit veins draining intestines and bladder (in *fresh water*) - the immune response is what cause the significant tissue damage

Question 48

What is the tx for blood flukes/schistosoma?

Answer 48

- prazquantel

Question 49

What is the prevention for blood flukes/schistosoma?

Answer 49

- avoid swimming in fresh water in high incidence areas like Africa