BIO1: Common Nemotode Infections

Question 1

Name 3 common worm infections

Answer 1

1. Enterobius vermicularis
2. Trichuris trichura
3. Ascaris Lumbricoides

All intestinal

Question 2

What are Geohelminths?

Answer 2

Intestinal nemotodes in which part of the development takes place outside the body

(Soil-transmitted helminths)

Question 3

How do Geohelminth infection occur?

Answer 3

Through contact with:

• parasite eggs
• infected larvae in contaminated soil or food

Question 4

What is infestation?

Answer 4

Term used for parasitic diseases caused by ectoparasites (e.g. ticks, lice, fleas) or worms (helminths)

Question 5

Enterobius vermicularis are known as pinworms or threadworms.

Where do they reside?

Answer 5

Adultworms (2-13mm) reside in the cecum (1^st part of large intestine

Question 6

Which age group is Enterobius vermicularis common in the UK?

Answer 6

Children under 10

Question 7

Who are the host of the Enterobius vermicularis infection?

Answer 7

Humans = only host

Question 8

Do the worms multiply in Enterobius vermicularis?

Answer 8

No

Question 9

How is Enterobius vermicularis transmitted?

Answer 9

Faecal-oral route (1 + 2)

1. Direct transmission from anal/perianal region to mouth by hand + fingernail contamination
2. Indirect transmission from exposure to eggs on surfaces, bed linen, clothes etc.
3. Contamination via airbourne eggs entering nose/mouth from contaminated dust
4. Retroinfection larvae hatch from eggs on anal mucosa + larvae migrate up the bowel

Question 10

What are the symptoms of Enterobius vermicularis?

Answer 10

• Pruritis ani - mild-acute painful itching @ night causing scratching of the perianal region;
  
  • lead to 2^ndary infections if skin integrity = compromised
• Vulvitis by worms entering vulva
• Insomnia
• Restlessness
• Appetite loss

No anaemia (as no blood feeding occurs + eosinophilia

Question 11

How is Enterobius vermicularis diagnosed?

Answer 11

Copromicroscopical examination - perianal scrapings/swabs from under the nails

• Use sellotape @ perianal region

Investigation consecutive days enhances sensitivity

Question 12

How can you prevent Enterobius vermicularis?

Answer 12

• Trim fingernails
• Wear cotton clothes + gloves during sleep
• Frequent washing of sheets + hands

Question 13

What is the treatment for Enterobius vermicularis?

Answer 13

• Mebendazole
  
  • children > 6 months
  • given as single dose + a 2^nd dose more than 2 weeks
  • Contraindicated in pregnancy
• Albendazole

Both in the benzimidazole class

Question 14

Which nemotode infections cause adultworms to reside in cecum?

Answer 14

Enterobius vermicularis + Trichuris triciura

Question 15

What are the symptoms of Trichuriasis?

Question 16

How do you diagnose Trichuriasis?

Question 17

Describe pathology of trichuriasis

Question 18

What is the treatment of trichuriasis?

Question 19

Which worm infection makes the largest worm?

Answer 19

Ascaris lumbricoides

Question 20

Which nemotode infections has adultworm residing in small intestine lumen?

Question 21

Ascaric lumbricoides + Ascaris suum are undistinguishable.

What is a key difference between the 2 infections?

Answer 21

Ascaris suum doesn’t infect humans

Question 22

What are the symptoms of ascariasis?

Question 23

How can you diagnose Ascariasis?

Question 24

Describe pathology of Ascariasis

Question 25

What is intussusception?

Question 26

What is the treatment for Ascariasis?

Answer 26

Mebendazole

Albendazole

Levamisole