Helminths

Question 1

Genus (genera)

Answer 1

always capitalized and italicized/underlined

Question 2

Species

Answer 2

always in lowercase

Question 3

Taxonomic ranks

Answer 3

domain
kingdom
phylum
class
order
family
genus
species

Question 4

3 main groups of helminth worms

Answer 4

Trematodes (flukes), cestodes (tapeworms), nematodes (roundworms)

Question 5

3 life cycle stages of a helminth

Answer 5

egg, larvae, adult

Question 6

Trematodes (flukes)

Answer 6

ovoid body shape

Question 7

Clonorchis sinensis

Answer 7

oriental liver fluke (china, japan, korea, vietnam, & taiwan) contracted from undercooked, infected fish

causes clonorchiasis & liver disease

mostly asymptomatic

Question 8

Schistosoma mansoni

Answer 8

blood fluke

causes schistosomiasis

snails are intermediate host

contracted from fecally contaminated water containing juveniles

Question 9

Schistosoma mansoni route of infection

Answer 9

juveniles penetrate skin, enter circulation, develop in intestinal walls

eggs penetrate intestinal wall & are passed in the feces

Question 10

Schistosoma mansoni symptoms

Answer 10

bloody diarrhea, abdominal pain, fever, & lethargy

Question 11

Paragonimus westermani

Answer 11

lung fluke

causes paragonimiasis

spread thru undercooked crabs & crayfish infected w/ cysts

Question 12

Paragonimus westermani

Answer 12

causes paragonimiasis

spread thru undercooked crabs & crayfish infected w/ cysts

Question 13

Paragonimus westermani route of infection

Answer 13

hatch in duodenum, penetrate intestinal wall & diaphragm, travel to lungs, eggs released into bronchioles, passed thru sputum or feces

Question 14

Cestodes (tapeworms)

Answer 14

adult body divided into segments called proglottids (sexual reproduction)

scolex (head/attachment)

Question 15

Taenia saginata

Answer 15

beef tapeworm

cattle intermediate host

mild nausea, diarrhea, abdominal pain, & headache

Question 16

Taenia solium

Answer 16

pork tapeworm

Question 17

Taenia pisiformis

Answer 17

dog tapeworm

hares & rabbits are intermediate hosts

Question 18

Nematodes (roundworms)

Answer 18

literally worms

Question 19

Ascaris lumbricoides

Answer 19

Roundworm

causes ascariases

consumption of fecally contaminated soil or food

juveniles emerge in intestines, penetrate walls, and migrate to lungs & other tissues

symptoms depend on tissue infected (mostly asymptomatic)

dx. eggs in feces

Question 20

Enterobius vermicularis

Answer 20

pinworm

causes enterobiasis

fecal-oral transmission often in orphanages and MH’s

females emerge at night to lay eggs in perianal region

dx. eggs collected on cellophane tape

Question 21

Necator americanus

Answer 21

hookworm

juveniles penetrate skin, enter blood, travel to lungs

bloody diarrhea, iron deficiency anemia

Question 22

Trichinella spiralis

Answer 22

roundworm

causes trichinosis

ingesting raw/undercooked pork or wild game infected with larvae

nausea, dyspepsia, diarrhea, muscle pain, fever, weakness

Question 23

Identify top & bottom specimens

Answer 23

Trematodes (flukes)
Top: Clonorchis sinensis egg
Bottom: Schistosoma mansoni egg

Question 24

Identify top & bottom specimens

Answer 24

Cestodes (tapeworms)
Top: Taenia pisiformis egg
Bottom: Taenia solium scolex

Question 25

Identify specimen

Answer 25

Cestodes (tapeworms)
Taenia pisiformis proglottid

Question 26

Identify specimens

Answer 26

Nematodes (roundworms)
Top: Enterobius vermicularis egg
Middle: Necator americanus egg
Bottom: Ascaris lumbricoides egg

Question 27

Schistosoma mansoni lifecycle

Answer 27

-1. eggs in feces (dx stage)
-2. eggs hatch in water, releasing miracidia
-3. miracidia penetrate snail tissue
-4. develop into sporocysts in snail
-5.cercariae released into water
-6. penetrate skin
-7. lose tails (penetration) & become schistosomulae
-8. circulation
-9. migrate to portal blood in liver & mature into adults
-10. adult worms pair & migrate to mesenteric venues of bowel/rectum to lay eggs