Helminth parasites

Question 1

Helminths

Answer 1

worm- like parasites that survive by feeding on a living host to gain nourishment & protection, sometimes resulting in illness to the host

Round worms (nematodes)

Flat worms

• tapeworms(cestodes)
• Flukes (trematodes)

Question 2

Helminth hosts & method of diagnosis

Answer 2

the host that harbours the larvae stage is called the intermediate host( ex.fish)

the host that harbours the adult worm is call the definitive host ( ex.human)

• infections are usually diagnosed by observing whole or segments of worms, larvae or eggs in clinical specimens

Question 3

Enterobius vermicularis common name, lifecycle

Answer 3

common name - Pinworm
most common helminth parasite in temperate climates

life cycle - includes 3 stages

1. egg
2. larva
3. Adult worm

Adults produce eggs- from which larvae emerge- larvae mature into adult worms

Question 4

Enterobius vermincularis diagnostic stage, infective stage

Answer 4

diagnostic stage
- female migrates to perianal region to lay eggs

Infective stage

• eggs develop to infective stage in 4-6 hours
• eggs distributed in the air & throughout the house
• eggs are ingested ( hand to mouth )

Question 5

Enterobius vermicularis collection & diagnosis

Answer 5

Eggs are not laid in the intestine therefore a stool sample is not an appropriate specimen

collection in the early morning before shower & before going to the bathroom

technique

• scotch (cellophane) tape preparation
• pinworm paddle

Question 6

Enterobius vermicularis diagnostic & treatment

Answer 6

diagnostic - recovery of eggs or yellowish white female adult worm

treatment

• Mebendazole
• Pyrantel Pamoate
• Warm tap water enemas
• May have to treat the entire household