Intestine Nematodes and Cestodes

Question 1

Intestinal Nematodes ( round worms )

Answer 1

Helminthic parasites, round worms with round cylindrical bodies.

Question 2

Intestinal Nematodes(Round worms)Stages ?

Answer 2

eggs , larvae and adult worms(male and female)

Question 3

Intestinal Nematodes(Round worms) transmission ?

Answer 3

obligatory soil phase indirectly faecal -oral

Some have direct person to person spread or autoinfection

Question 4

Intestinal Nematodes(Round worms) Infection is either by

Answer 4

ingestion or skin penetration

Question 5

Intestinal nematodes that need soil phase to complete the life cycle are ?

Answer 5

1. Trichuris trichiura (whipworm)
2. Ancylostoma duodenale (hookworm)
3. Ascaris lumbricoides (roundworm)

Question 6

Intestinal nematodes that do not need soil phase are?

Answer 6

1-Enterobius vermicularis (pinworm)

2-Strongyloides stericoralis (threadworm)

Question 7

Trichuris trichiura ( whipworm ) (infected organ, reservoir , host , migration)

Answer 7

Nematode of large intestine
No animal reservoir
Man is the defenitive or final host
No lung migration

Question 8

Trichuris trichiura (whipworm) Infective stage

Answer 8

embryonated eggs

Question 9

Trichuris trichiura (whipworm) Life cycle ? (6)

Answer 9

1. Eggs hatch in small intestine
2. releasing larvae that migrate to the caecum
3. Larvae mature into adult worms
4. The fertilized female worm lays eggs(un-embyronated) in the caecum and ascending colon
5. Eggs pass to the soil in faeces and develop in soil into embryonated infectious eggs
6. Embryonated eggs are then ingested and the cycle repeated

Question 10

Trichuris trichiura (whipworm) C/F ?(4)

Answer 10

1. Abdominal discomfort
2. Bloody diarrhoea(dysentry)
3. Rectal prolapse
4. Intestinal obstruction might occur

Question 11

Trichuris trichiura (whipworm)Diagnosis ?

Answer 11

microscopy of faeces show typical eggs

Question 12

Trichuris trichiura (whipworm)Treatment and control?

Answer 12

Mebendazole

sanitation and personal hygiene

Question 13

Ascaris lumbricoides ( Roundworms ) (infected organ, reservoir, migration

Answer 13

Nematode of small intestines
No animal reservoir
Lung migration is present

Question 14

Ascaris lumbricoides Infective stage is

Answer 14

embryonated eggs

Question 15

Ascaris lumbricoides life cycle ?(4)

Answer 15

1. Embryonated eggs are ingested and hatch in the small intestine releasing larvae
2. Larvae migrate from the intestine to the lung and back to the small intestine where they mature into adult worms
3. The fertilized female worm lays eggs (unembyronated) that pass in faeces into the soil
4. The eggs develop in soil into embryonated infectious eggs,ready to be ingested and repeat the cycle

Question 16

Ascaris lumbricoides C/F

Answer 16

symptoms depend on worm load
 Light load: asymptomatic
Heavy load cause :  
1.abdominal discomfort 
2.Diarrhoea 
3.Malnutrition 
4.Intestinal obstruction 
5.Larvae in lungs cause allergic reaction with pneumonitis manifested as cough dysnoea and eosinophilia

Question 17

Ascaris lumbricoides Diagnosis ?

Answer 17

finding the eggs in faeces

Question 18

Ascaris lumbricoides Treatment and control?

Answer 18

Mebendazole

education,good sanitation,personal hygiene especially in food handlers

Question 19

Ancylostoma duodenale ( Hookworm ) ( infected organ , migration )

Answer 19

Nematode of small intestine

Lung migration is present in life cycle

Question 20

Ancylostoma duodenale infective stage ?

Answer 20

larvae

Question 21

Ancylostoma duodenale Life cycle ?(5)

Answer 21

1. Embryonated eggs hatch in the soil releasing the infective larvae
2. Larvae penetrate the skin and migrate first by blood circulation to the lungs and then to the small intestines where they mature into adult worms
3. Adult worms attach to the mucosa of small intestine.
4. Female worm lays eggs which pass in faeces into the soil
5. The eggs hatch and mature into larvae which can penetrate the skin and repeat the cycle

Question 22

Ancylostoma duodenale Pathogenesis

Answer 22

the worms ingest blood from the human small intestinal mucosa (100 ml daily by 500 adult worms)

Question 23

Ancylostoma duodenale C/F ? (4)

Answer 23

1. itch (ground itch) at skin penetration site 2.Migration of larvae to lungs cause pneumonitis with cough and dyspnoea
2. Duodenal ulcer
3. Iron deficiency anaemia

Question 24

Ancylostoma duodenale Diagnosis ?

Answer 24

microscopy of faeces show the typical egg containing a developing larva

Question 25

Ancylostoma duodenale Treatment and control?

Answer 25

Mebendazole | Iron supplements to correct the anaemia education good sanitation personal hygiene treatment of cases

Question 26

Strongyloides stercoralis (Threadworm) route of infection ,reservoir

Answer 26

directly faecal-skin direct anal contact (including sexual contact) by autoinfection No animal reservoir

Question 27

Strongyloides stercoralis infective stage ?

Answer 27

the filariform larvae

Question 28

Strongyloides stercoralis life cycle?(6)

Answer 28

1. Filariform larvae in soil penetrate the skin exposed to soil 2. Larvae migrate via the blood to the heart,lungs and trachea and are swallowed 3. Larvae reach the small intestine and mature into adult worms 4. Female adult worm producse eggs 5. The eggs hatch in small intestine and release rhabditiform larvae(non infective larvae ) which pass out in the faeces into the soil 6. The rhabditiform larvae then undergo any of three phase

Question 29

The three phase of rhabditiform larvae

Answer 29

1-it develops into free-living adult worms in the soil and produce infective filariform larvae which can penetrate exposed skin 2-it develops into filariform infective larvae in the soil and these can penetrate exposed skin. There is no development of free-living adult worms 3-it develops into infective filariform larvae while passing down the small intestines into the large intestine and these can reinfect host by penetration of intestinal mucosa or perianal skin (autoinfection)

Question 30

Strongyloides stercoralis C/F ?(6)

Answer 30

1. itch (ground itch) at skin penetrating site 2. allergic pneumonitis 3. abdominal symptoms and diarrhoea 4. small bowl obstruction 5. Paralytic ileus 6. gut ulceration

Question 31

Strongyloides stercoralis Diagnosis

Answer 31

microscopy of repeated faeces specimens or duodenal aspirate show the filariform larvae. This indicates acute infection

Question 32

Strongyloides stercoralis Treatment and control?

Answer 32

Thiabendazole | education, good sanitation, personal hygiene and treatment of cases

Question 33

Enterobius vericularis (pin worm) infected organ, host , migration , route of infection ,

Answer 33

Nematode of large intestine Man is the definitive or final host No lung migration Spread is person-to-person by direct contact or fomites or autoinfection

Question 34

Enterobius vericularis Infective stage

Answer 34

embryonated eggs

Question 35

Enterobius vericularis life cycle?(4)

Answer 35

1. Eggs hatch in small intestine and release larvae which mature to adult worms 2. The worms ,male and female, migrate to the caecum 3. Fertilised female worm migrate to perianal skin region at night to lay eggs and then die 4. Eggs are deposited on perianal skin,on under-clothes,bedding or under scratching finger-nails and ingested (autoinfection) to repeat the cycle

Question 36

Enterobius vericularis C/F ?

Answer 36

perianal itching (pruritis ani)

Question 37

Enterobius vericularis Diagnosis

Answer 37

1. adult worms may be seen on perianal skin | 2. eggs can be seen microscopically on cellophane tape pressed to the anus.

Question 38

Enterobius vericularis treatment and control?

Answer 38

Mebendazole( to the whole family) | hand and nail hygiene,washing of beddings and case treatment

Question 39

Cestodes ( Tapeworms)

Answer 39

segmented tape-like worms (tape worms)

Question 40

Cestodes ( Tapeworms)(4)?

Answer 40

1. Taenia saginata 2. Taenia solium 3. Ecchinococcus granulosus (hydatid worm) 4. Hymenolepsis nana(dwarf worm)

Question 41

Humans can be infected in two ways

Answer 41

1-As definitive or final host | 2As intermediate host

Question 42

As definitive or final host

Answer 42

the adult worm in the gut after ingesting encysted larvae in incompletely cooked meat. This produces intestinal disease e.g. infection by Taenia saginata

Question 43

As intermediate host

Answer 43

larvae in tissues after ingesting eggs in faecally contaminated food or water. This produces tissue disease from encysted larvae e.g.as in infection by Echinococcus granulosus