Helminths

Question 1

platyhelminthes (flatworms)
- trematoda (flukes)
- cestoda (tapeworms)

nemathelminthes (roundworms)

Answer 1

metazoa (helminths)

Question 2

elongated and tapered at both ends, round in cross-section (barrel-shaped)
complete digest system
body cavity is present

Answer 2

parasitic nematodes - roundworms

Question 3

leaf-like body (except Schistosoma)
has two suckers
non-segmented body
hermaphroditic (except Schistosoma)

Answer 3

parasitic trematodes - flukes

Question 4

body is ribbon-like with a chain of segments (proglottids)
each proglottid contains male and female sexual organs
nutrients directly absorb from their host through their body coverings

Answer 4

parasitic cestodes - tapeworms

Question 5

enterobius vermicularis
ascaris lumbricoides
trichuris trichiura
filarial nematodes

Answer 5

nematodes - roundworms

Question 6

adult worms are small and whitish
female has a long, pin-shaped tail (pinworm)
adult worms stay in cecum of infected individuals
eggs are elongate to oval shaped, and slightly flattened on one side

Answer 6

enterobius vermicularis

Question 7

intense perianal pruritus at night due to migrating gravid female and hypersensitivity against eggs

teeth grinding, insomnia, nervousness - associated with toxic effects of unknown parasitic protein

infectious stage: embryonated eggs

Answer 7

enterobiasis: intestinal infection

Question 8

adult worms are big and round (roundworm)
male has a coiled tail
complete entire life cycle in a human host
eggs have thick shell with an external mammilated layer

Answer 8

ascaris lumbricoides

Question 9

intestinal symptoms: ascariasis
- due to large body size adult worms, intestinal obstruction, malnutrition, abdominal pain
- rarely, adult worm force their way into other organs and causes bowel perforation, peritonitis, vomiting, passing out of adult worm from mouth

respiratory symptoms: loeffler syndrome
- due to host hypersensitivity reaction against the antigens of the migrating larvae
- abundant eosinophils accumulate in affect lungs
- shortness of breath, fever, chest pain, cough

transmission: soil

infectious stage: eggs

Answer 9

ascaris lumbricoides

Question 10

adult worm has a whip-like anterior end; male has a coiled posterior end, female has a straight posterior end (whipworm)
adults stay in large intestine of humans
egg is barrel-shaped, thick-shelled, and has a pair of polar plugs at each end

Answer 10

Trichuris trichiura

Question 11

a common soil-transmitted worm infection
adult worms burrow their whip-like anterior ends into intestinal mucosa
heavy infection: lower abdominal pain, distention, and diarrhea
severe infection in children: profuse bloody diarrhea, cramps, and rectal prolapse
rectal prolapse due to abundant whipworms burrow rectum wall, loosen elasticity of epithelium and weakening surrounding muscles

Answer 11

trichuriasis: gastrointestinal infection

Question 12

wuchereria bancrofti
burgia malayi
burgia timori

Answer 12

lymphatic filarial worms

Question 13

transmission: mosquito borne

lymphatic filariasis
- fever, painful lymph nodes, oedema; lymphatic system inflammation trigger by antigens of circulating microfilaria and adult worms. limb swelling due to lymphangitis

tropical pulmonary eosinophilia
- fever, dry cough, difficulty in breathing, sticky or bloody sputum; lung inflammation trigger by antigens of microfilaria trapped in the lung

Answer 13

lymphatic filarial worm

Question 14

adult worms live in lymph nodes of afferet lymphatics, cause lymphatic dilation and thickening of vessel walls

antigens of adult worms and microfilaria trigger infiltration of immune cells (eosinophilas and macrophages), endothelial and connective tissue proliferation

persistent antigens cause persistent inflammation and proliferative processes which then cause lymphatic vessels damage and total lymphatic obstruction. Aggravated by second bacterial infection can lead elephantiasis

Answer 14

elephantiasis

Question 15

taenia saginata
taenia solium
echinococcus granulosus

Answer 15

cestodes

Question 16

scolex (head)
- has suckers for attachment

neck
- next to scolex
- a structure from which new proglottids are continuously produced

strobila (body)
- consists of a many proglottid segments
- immature: do not have a fully mature reproductive system
- mature: have fully mature male and female sex organs
- gravid: produce many eggs

Answer 16

adult cestodes

Question 17

scolex: sucker

Answer 17

taenia saginata (beef tapeworm)

Question 18

scolex: hooklets and sucker

Answer 18

taenia solium (pork tapeworm)

Question 19

large body size adult worms in GI tract: abdominal pain, distension, nausea, malnutrition

diagnosis: microscopic detection of eggs or proglottids in faecal specimen

Answer 19

human taeniasis

Question 20

symptoms depend on sites where larvae settled: brain, eye, muscle, subcutaneous

diagnosis: imaging- CT scan, MRI, biopsy and microscopy to detect larvae, serological test

Answer 20

human cysticercosis

Question 21

infections remain asymptomatic for many years before symptoms occur; symptoms depend on the affected organs

liver and lungs are the most common affected organs

rupture of cysts can produce fever, inflammation, anaphylactic shock, and secondary echinococcosis

Answer 21

cystic echinococcosis

Question 22

rash and itchy skin within days after exposed to freshwater that harbor the intermediate snail host

related to host immune reaction to migrating schistosomulae

Answer 22

schistosomiasis - swimmer’s itch

Question 23

fever, cough, muscle aches, diarrhea, non-itching rash

Answer 23

acute schistosomiasis - katayama fever